File: System\Windows\Forms\Controls\DataGridView\DataGridViewColumnCollection.cs
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Project: src\src\System.Windows.Forms\System.Windows.Forms.csproj (System.Windows.Forms)
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections;
using System.ComponentModel;
using System.Globalization;
 
namespace System.Windows.Forms;
 
/// <summary>
///  Represents a collection of <see cref="DataGridViewColumn"/> objects in the
///  <see cref="DataGridView"/> control.
/// </summary>
[ListBindable(false)]
public partial class DataGridViewColumnCollection : BaseCollection, IList
{
    private CollectionChangeEventHandler? _onCollectionChanged;
    private readonly List<DataGridViewColumn> _items = [];
    private List<DataGridViewColumn>? _itemsSorted;
    private int _lastAccessedSortedIndex = -1;
    private int _columnCountsVisible, _columnCountsVisibleSelected;
    private int _columnsWidthVisible, _columnsWidthVisibleFrozen;
    private static readonly ColumnOrderComparer s_columnOrderComparer = new();
 
    /* IList interface implementation */
 
    bool IList.IsFixedSize => false;
 
    bool IList.IsReadOnly => false;
 
    object? IList.this[int index]
    {
        get => this[index];
        set => throw new NotSupportedException();
    }
 
    int IList.Add(object? value) => Add((DataGridViewColumn)value!);
 
    void IList.Clear() => Clear();
 
    bool IList.Contains(object? value) => _items.Contains(value);
 
    int IList.IndexOf(object? value) => _items.IndexOf((DataGridViewColumn)value!);
 
    void IList.Insert(int index, object? value) => Insert(index, (DataGridViewColumn)value!);
 
    void IList.Remove(object? value) => Remove((DataGridViewColumn)value!);
 
    void IList.RemoveAt(int index) => RemoveAt(index);
 
    /* ICollection interface implementation */
 
    int ICollection.Count => _items.Count;
 
    bool ICollection.IsSynchronized => false;
 
    object ICollection.SyncRoot => this;
 
    void ICollection.CopyTo(Array array, int index) => ((ICollection)_items).CopyTo(array, index);
 
    /* IEnumerable interface implementation */
 
    IEnumerator IEnumerable.GetEnumerator() => _items.GetEnumerator();
 
    public DataGridViewColumnCollection(DataGridView dataGridView)
    {
        InvalidateCachedColumnCounts();
        InvalidateCachedColumnsWidths();
        DataGridView = dataGridView;
    }
 
    internal static IComparer<DataGridViewColumn?> ColumnCollectionOrderComparer => s_columnOrderComparer;
 
    protected override ArrayList List => ArrayList.Adapter(_items);
 
    protected DataGridView DataGridView { get; }
 
    /// <summary>
    ///  Retrieves the DataGridViewColumn with the specified index.
    /// </summary>
    public DataGridViewColumn this[int index] => _items[index];
 
    /// <summary>
    ///  Retrieves the DataGridViewColumn with the Name provided.
    /// </summary>
    public DataGridViewColumn? this[string columnName]
    {
        get
        {
            ArgumentNullException.ThrowIfNull(columnName);
 
            int itemCount = _items.Count;
            for (int i = 0; i < itemCount; ++i)
            {
                DataGridViewColumn dataGridViewColumn = _items[i];
                // NOTE: case-insensitive
                if (string.Equals(dataGridViewColumn.Name, columnName, StringComparison.OrdinalIgnoreCase))
                {
                    return dataGridViewColumn;
                }
            }
 
            return null;
        }
    }
 
    public event CollectionChangeEventHandler? CollectionChanged
    {
        add => _onCollectionChanged += value;
        remove => _onCollectionChanged -= value;
    }
 
    internal int ActualDisplayIndexToColumnIndex(int actualDisplayIndex, DataGridViewElementStates includeFilter)
    {
        // Microsoft: is there a faster way to get the column index?
        DataGridViewColumn? dataGridViewColumn = GetFirstColumn(includeFilter);
        for (int i = 0; i < actualDisplayIndex; i++)
        {
            dataGridViewColumn = GetNextColumn(dataGridViewColumn!, includeFilter, DataGridViewElementStates.None);
        }
 
        return dataGridViewColumn?.Index ?? -1;
    }
 
    /// <summary>
    ///  Adds a <see cref="DataGridViewColumn"/> to this collection.
    /// </summary>
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public virtual int Add(string? columnName, string? headerText)
    {
        DataGridViewTextBoxColumn dataGridViewTextBoxColumn = new DataGridViewTextBoxColumn
        {
            Name = columnName,
            HeaderText = headerText
        };
 
        return Add(dataGridViewTextBoxColumn);
    }
 
    /// <summary>
    ///  Adds a <see cref="DataGridViewColumn"/> to this collection.
    /// </summary>
    public virtual int Add(DataGridViewColumn dataGridViewColumn)
    {
        Debug.Assert(DataGridView is not null);
        if (DataGridView.NoDimensionChangeAllowed)
        {
            throw new InvalidOperationException(SR.DataGridView_ForbiddenOperationInEventHandler);
        }
 
        if (DataGridView.InDisplayIndexAdjustments)
        {
            // We are within columns display indexes adjustments.
            // We do not allow changing the column collection while adjusting display indexes.
            throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
        }
 
        DataGridView.OnAddingColumn(dataGridViewColumn);   // will throw an exception if the addition is illegal
 
        InvalidateCachedColumnsOrder();
        _items.Add(dataGridViewColumn);
        int index = _items.IndexOf(dataGridViewColumn);
        dataGridViewColumn.Index = index;
        dataGridViewColumn.DataGridView = DataGridView;
        UpdateColumnCaches(dataGridViewColumn, true);
        DataGridView.OnAddedColumn(dataGridViewColumn);
        OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Add, dataGridViewColumn), false /*changeIsInsertion*/, new Point(-1, -1));
#if DEBUG
        Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
        return index;
    }
 
    public virtual void AddRange(params DataGridViewColumn[] dataGridViewColumns)
    {
        ArgumentNullException.ThrowIfNull(dataGridViewColumns);
 
        Debug.Assert(DataGridView is not null);
        if (DataGridView.NoDimensionChangeAllowed)
        {
            throw new InvalidOperationException(SR.DataGridView_ForbiddenOperationInEventHandler);
        }
 
        if (DataGridView.InDisplayIndexAdjustments)
        {
            // We are within columns display indexes adjustments.
            // We do not allow changing the column collection while adjusting display indexes.
            throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
        }
 
        // Order the columns by ascending DisplayIndex so that their display indexes are not altered by the operation.
        // The columns with DisplayIndex == -1 are left untouched relative to each other and put at the end of the array.
        List<DataGridViewColumn> initialColumns = new(dataGridViewColumns.Length);
        List<DataGridViewColumn> sortedColumns = new(dataGridViewColumns.Length);
 
        // All columns with DisplayIndex != -1 are put into the initialColumns array
        foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
        {
            if (dataGridViewColumn.DisplayIndex != -1)
            {
                initialColumns.Add(dataGridViewColumn);
            }
        }
 
        // Those columns are copied into the sortedColumns array in an N^2 sort algo that
        // does not disrupt the order of columns with identical DisplayIndex values.
        int smallestDisplayIndex, smallestIndex, index;
 
        while (initialColumns.Count > 0)
        {
            smallestDisplayIndex = int.MaxValue;
            smallestIndex = -1;
            for (index = 0; index < initialColumns.Count; index++)
            {
                DataGridViewColumn dataGridViewColumn = initialColumns[index];
                if (dataGridViewColumn.DisplayIndex < smallestDisplayIndex)
                {
                    smallestDisplayIndex = dataGridViewColumn.DisplayIndex;
                    smallestIndex = index;
                }
            }
 
            Debug.Assert(smallestIndex >= 0);
            sortedColumns.Add(initialColumns[smallestIndex]);
            initialColumns.RemoveAt(smallestIndex);
        }
 
        // The columns with DisplayIndex == -1 are append at the end of sortedColumns
        // without disrupting their relative order.
        foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
        {
            if (dataGridViewColumn.DisplayIndex == -1)
            {
                sortedColumns.Add(dataGridViewColumn);
            }
        }
 
        // Finally the dataGridViewColumns is reconstructed using the sortedColumns.
        index = 0;
        foreach (DataGridViewColumn dataGridViewColumn in sortedColumns)
        {
            dataGridViewColumns[index] = dataGridViewColumn;
            index++;
        }
 
        DataGridView.OnAddingColumns(dataGridViewColumns);   // will throw an exception if the addition is illegal
 
        foreach (DataGridViewColumn dataGridViewColumn in dataGridViewColumns)
        {
            InvalidateCachedColumnsOrder();
            _items.Add(dataGridViewColumn);
            index = _items.IndexOf(dataGridViewColumn);
            dataGridViewColumn.Index = index;
            dataGridViewColumn.DataGridView = DataGridView;
            UpdateColumnCaches(dataGridViewColumn, true);
            DataGridView.OnAddedColumn(dataGridViewColumn);
        }
 
        OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Refresh, null), false /*changeIsInsertion*/, new Point(-1, -1));
#if DEBUG
        Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
    }
 
    public virtual void Clear()
    {
        if (Count > 0)
        {
            if (DataGridView.NoDimensionChangeAllowed)
            {
                throw new InvalidOperationException(SR.DataGridView_ForbiddenOperationInEventHandler);
            }
 
            if (DataGridView.InDisplayIndexAdjustments)
            {
                // We are within columns display indexes adjustments.
                // We do not allow changing the column collection while adjusting display indexes.
                throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
            }
 
            for (int columnIndex = 0; columnIndex < Count; columnIndex++)
            {
                DataGridViewColumn dataGridViewColumn = this[columnIndex];
                // Detach the column...
                dataGridViewColumn.DataGridView = null;
                // ...and its potential header cell
                if (dataGridViewColumn.HasHeaderCell)
                {
                    dataGridViewColumn.HeaderCell.DataGridView = null;
                }
            }
 
            DataGridViewColumn[] aColumns = new DataGridViewColumn[_items.Count];
            CopyTo(aColumns, 0);
 
            DataGridView.OnClearingColumns();
            InvalidateCachedColumnsOrder();
            _items.Clear();
            InvalidateCachedColumnCounts();
            InvalidateCachedColumnsWidths();
            foreach (DataGridViewColumn dataGridViewColumn in aColumns)
            {
                DataGridView.OnColumnRemoved(dataGridViewColumn);
                DataGridView.OnColumnHidden(dataGridViewColumn);
            }
 
            OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Refresh, null), false /*changeIsInsertion*/, new Point(-1, -1));
#if DEBUG
            Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
        }
    }
 
    internal int ColumnIndexToActualDisplayIndex(int columnIndex, DataGridViewElementStates includeFilter)
    {
        // map the column index to the actual display index
        DataGridViewColumn? dataGridViewColumn = GetFirstColumn(includeFilter);
        int actualDisplayIndex = 0;
        while (dataGridViewColumn is not null && dataGridViewColumn.Index != columnIndex)
        {
            dataGridViewColumn = GetNextColumn(dataGridViewColumn, includeFilter, DataGridViewElementStates.None);
            actualDisplayIndex++;
        }
 
        return actualDisplayIndex;
    }
 
    /// <summary>
    ///  Checks to see if a DataGridViewColumn is contained in this collection.
    /// </summary>
    public virtual bool Contains(DataGridViewColumn dataGridViewColumn) => _items.IndexOf(dataGridViewColumn) != -1;
 
    public virtual bool Contains(string columnName)
    {
        ArgumentNullException.ThrowIfNull(columnName);
 
        int itemCount = _items.Count;
        for (int i = 0; i < itemCount; ++i)
        {
            DataGridViewColumn dataGridViewColumn = _items[i];
            // NOTE: case-insensitive
            if (string.Compare(dataGridViewColumn.Name, columnName, true, CultureInfo.InvariantCulture) == 0)
            {
                return true;
            }
        }
 
        return false;
    }
 
    public void CopyTo(DataGridViewColumn[] array, int index)
    {
        _items.CopyTo(array, index);
    }
 
    internal bool DisplayInOrder(int columnIndex1, int columnIndex2)
    {
        int displayIndex1 = _items[columnIndex1].DisplayIndex;
        int displayIndex2 = _items[columnIndex2].DisplayIndex;
        return displayIndex1 < displayIndex2;
    }
 
    internal DataGridViewColumn? GetColumnAtDisplayIndex(int displayIndex)
    {
        if (displayIndex < 0 || displayIndex >= _items.Count)
        {
            return null;
        }
 
        DataGridViewColumn dataGridViewColumn = _items[displayIndex];
        if (dataGridViewColumn.DisplayIndex == displayIndex)
        {
            // Performance gain if display indexes coincide with indexes.
            return dataGridViewColumn;
        }
 
        for (int columnIndex = 0; columnIndex < _items.Count; columnIndex++)
        {
            dataGridViewColumn = _items[columnIndex];
            if (dataGridViewColumn.DisplayIndex == displayIndex)
            {
                return dataGridViewColumn;
            }
        }
 
        Debug.Fail("no column found in GetColumnAtDisplayIndex");
        return null;
    }
 
    /// <summary>
    ///  Returns the index of a column, taking into account DisplayIndex properties
    ///  and the invisibility of other columns
    /// </summary>
    internal int GetVisibleIndex(DataGridViewColumn column)
    {
        for (int i = 0; i < Count; i++)
        {
            int index = ActualDisplayIndexToColumnIndex(i, DataGridViewElementStates.Visible);
            if (index != -1 && _items[index] == column)
            {
                return i;
            }
        }
 
        return -1;
    }
 
    public int GetColumnCount(DataGridViewElementStates includeFilter)
    {
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        // cache returned value and reuse it as long as none
        // of the column's state has changed.
        switch (includeFilter)
        {
            case DataGridViewElementStates.Visible:
                if (_columnCountsVisible != -1)
                {
                    return _columnCountsVisible;
                }
 
                break;
            case DataGridViewElementStates.Visible | DataGridViewElementStates.Selected:
                if (_columnCountsVisibleSelected != -1)
                {
                    return _columnCountsVisibleSelected;
                }
 
                break;
        }
 
        int columnCount = 0;
        if ((includeFilter & DataGridViewElementStates.Resizable) == 0)
        {
            for (int columnIndex = 0; columnIndex < _items.Count; columnIndex++)
            {
                if (_items[columnIndex].StateIncludes(includeFilter))
                {
                    columnCount++;
                }
            }
 
            switch (includeFilter)
            {
                case DataGridViewElementStates.Visible:
                    _columnCountsVisible = columnCount;
                    break;
                case DataGridViewElementStates.Visible | DataGridViewElementStates.Selected:
                    _columnCountsVisibleSelected = columnCount;
                    break;
            }
        }
        else
        {
            DataGridViewElementStates correctedIncludeFilter = includeFilter & ~DataGridViewElementStates.Resizable;
            for (int columnIndex = 0; columnIndex < _items.Count; columnIndex++)
            {
                if (_items[columnIndex].StateIncludes(correctedIncludeFilter) &&
                    _items[columnIndex].Resizable == DataGridViewTriState.True)
                {
                    columnCount++;
                }
            }
        }
 
        return columnCount;
    }
 
    internal int GetColumnCount(DataGridViewElementStates includeFilter, int fromColumnIndex, int toColumnIndex)
    {
        Debug.Assert((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
                     DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) == 0);
        Debug.Assert((includeFilter & DataGridViewElementStates.Resizable) == 0);
        Debug.Assert(DisplayInOrder(fromColumnIndex, toColumnIndex));
        Debug.Assert(_items[toColumnIndex].StateIncludes(includeFilter));
 
        int jumpColumns = 0;
        DataGridViewColumn? dataGridViewColumn = _items[fromColumnIndex];
 
        while (dataGridViewColumn != _items[toColumnIndex])
        {
            dataGridViewColumn = GetNextColumn(
                dataGridViewColumn, includeFilter,
                DataGridViewElementStates.None);
            Debug.Assert(dataGridViewColumn is not null);
            if (dataGridViewColumn.StateIncludes(includeFilter))
            {
                jumpColumns++;
            }
        }
 
        return jumpColumns;
    }
 
    private int GetColumnSortedIndex(DataGridViewColumn dataGridViewColumn)
    {
        Debug.Assert(dataGridViewColumn is not null);
        Debug.Assert(_itemsSorted is not null);
        Debug.Assert(_lastAccessedSortedIndex == -1 ||
            _lastAccessedSortedIndex < Count);
 
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        if (_lastAccessedSortedIndex != -1 &&
            _itemsSorted[_lastAccessedSortedIndex] == dataGridViewColumn)
        {
            return _lastAccessedSortedIndex;
        }
 
        int index = 0;
        while (index < _itemsSorted.Count)
        {
            if (dataGridViewColumn.Index == _itemsSorted[index].Index)
            {
                _lastAccessedSortedIndex = index;
                return index;
            }
 
            index++;
        }
 
        return -1;
    }
 
    internal float GetColumnsFillWeight(DataGridViewElementStates includeFilter)
    {
        Debug.Assert((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
                     DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) == 0);
 
        float weightSum = 0F;
        for (int columnIndex = 0; columnIndex < _items.Count; columnIndex++)
        {
            if (_items[columnIndex].StateIncludes(includeFilter))
            {
                weightSum += _items[columnIndex].FillWeight;
            }
        }
 
        return weightSum;
    }
 
    public int GetColumnsWidth(DataGridViewElementStates includeFilter)
    {
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        // cache returned value and reuse it as long as none
        // of the column's state/thickness has changed.
        switch (includeFilter)
        {
            case DataGridViewElementStates.Visible:
                if (_columnsWidthVisible != -1)
                {
                    return _columnsWidthVisible;
                }
 
                break;
            case DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen:
                if (_columnsWidthVisibleFrozen != -1)
                {
                    return _columnsWidthVisibleFrozen;
                }
 
                break;
        }
 
        int columnsWidth = 0;
        for (int columnIndex = 0; columnIndex < _items.Count; columnIndex++)
        {
            if (_items[columnIndex].StateIncludes(includeFilter))
            {
                columnsWidth += _items[columnIndex].Thickness;
            }
        }
 
        switch (includeFilter)
        {
            case DataGridViewElementStates.Visible:
                _columnsWidthVisible = columnsWidth;
                break;
            case DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen:
                _columnsWidthVisibleFrozen = columnsWidth;
                break;
        }
 
        return columnsWidth;
    }
 
    public DataGridViewColumn? GetFirstColumn(DataGridViewElementStates includeFilter)
    {
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        if (_itemsSorted is null)
        {
            UpdateColumnOrderCache();
        }
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        int index = 0;
        while (index < _itemsSorted.Count)
        {
            DataGridViewColumn dataGridViewColumn = _itemsSorted[index];
            if (dataGridViewColumn.StateIncludes(includeFilter))
            {
                _lastAccessedSortedIndex = index;
                return dataGridViewColumn;
            }
 
            index++;
        }
 
        return null;
    }
 
    public DataGridViewColumn? GetFirstColumn(
        DataGridViewElementStates includeFilter,
        DataGridViewElementStates excludeFilter)
    {
        if (excludeFilter == DataGridViewElementStates.None)
        {
            return GetFirstColumn(includeFilter);
        }
 
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        if ((excludeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(excludeFilter)));
        }
 
        if (_itemsSorted is null)
        {
            UpdateColumnOrderCache();
        }
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        int index = 0;
        while (index < _itemsSorted.Count)
        {
            DataGridViewColumn dataGridViewColumn = _itemsSorted[index];
            if (dataGridViewColumn.StateIncludes(includeFilter) &&
                dataGridViewColumn.StateExcludes(excludeFilter))
            {
                _lastAccessedSortedIndex = index;
                return dataGridViewColumn;
            }
 
            index++;
        }
 
        return null;
    }
 
    public DataGridViewColumn? GetLastColumn(
        DataGridViewElementStates includeFilter,
        DataGridViewElementStates excludeFilter)
    {
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        if ((excludeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(excludeFilter)));
        }
 
        if (_itemsSorted is null)
        {
            UpdateColumnOrderCache();
        }
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        int index = _itemsSorted.Count - 1;
        while (index >= 0)
        {
            DataGridViewColumn dataGridViewColumn = _itemsSorted[index];
            if (dataGridViewColumn.StateIncludes(includeFilter) &&
                dataGridViewColumn.StateExcludes(excludeFilter))
            {
                _lastAccessedSortedIndex = index;
                return dataGridViewColumn;
            }
 
            index--;
        }
 
        return null;
    }
 
    public DataGridViewColumn? GetNextColumn(
        DataGridViewColumn dataGridViewColumnStart,
        DataGridViewElementStates includeFilter,
        DataGridViewElementStates excludeFilter)
    {
        ArgumentNullException.ThrowIfNull(dataGridViewColumnStart);
 
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        if ((excludeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(excludeFilter)));
        }
 
        if (_itemsSorted is null)
        {
            UpdateColumnOrderCache();
        }
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        int index = GetColumnSortedIndex(dataGridViewColumnStart);
        if (index == -1)
        {
            bool columnFound = false;
            int indexMin = int.MaxValue, displayIndexMin = int.MaxValue;
            for (index = 0; index < _items.Count; index++)
            {
                DataGridViewColumn dataGridViewColumn = _items[index];
                if (dataGridViewColumn.StateIncludes(includeFilter) &&
                    dataGridViewColumn.StateExcludes(excludeFilter) &&
                    (dataGridViewColumn.DisplayIndex > dataGridViewColumnStart.DisplayIndex ||
                     (dataGridViewColumn.DisplayIndex == dataGridViewColumnStart.DisplayIndex &&
                      dataGridViewColumn.Index > dataGridViewColumnStart.Index)))
                {
                    if (dataGridViewColumn.DisplayIndex < displayIndexMin ||
                        (dataGridViewColumn.DisplayIndex == displayIndexMin &&
                         dataGridViewColumn.Index < indexMin))
                    {
                        indexMin = index;
                        displayIndexMin = dataGridViewColumn.DisplayIndex;
                        columnFound = true;
                    }
                }
            }
 
            return columnFound ? _items[indexMin] : null;
        }
        else
        {
            index++;
            while (index < _itemsSorted.Count)
            {
                DataGridViewColumn dataGridViewColumn = _itemsSorted[index];
 
                if (dataGridViewColumn.StateIncludes(includeFilter) && dataGridViewColumn.StateExcludes(excludeFilter))
                {
                    _lastAccessedSortedIndex = index;
                    return dataGridViewColumn;
                }
 
                index++;
            }
        }
 
        return null;
    }
 
    public DataGridViewColumn? GetPreviousColumn(
        DataGridViewColumn dataGridViewColumnStart,
        DataGridViewElementStates includeFilter,
        DataGridViewElementStates excludeFilter)
    {
        ArgumentNullException.ThrowIfNull(dataGridViewColumnStart);
 
        if ((includeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(includeFilter)));
        }
 
        if ((excludeFilter & ~(DataGridViewElementStates.Displayed | DataGridViewElementStates.Frozen | DataGridViewElementStates.Resizable |
            DataGridViewElementStates.ReadOnly | DataGridViewElementStates.Selected | DataGridViewElementStates.Visible)) != 0)
        {
            throw new ArgumentException(string.Format(SR.DataGridView_InvalidDataGridViewElementStateCombination, nameof(excludeFilter)));
        }
 
        if (_itemsSorted is null)
        {
            UpdateColumnOrderCache();
        }
#if DEBUG
        Debug.Assert(VerifyColumnOrderCache());
#endif
        int index = GetColumnSortedIndex(dataGridViewColumnStart);
        if (index == -1)
        {
            bool columnFound = false;
            int indexMax = -1, displayIndexMax = -1;
            for (index = 0; index < _items.Count; index++)
            {
                DataGridViewColumn dataGridViewColumn = _items[index];
                if (dataGridViewColumn.StateIncludes(includeFilter) &&
                    dataGridViewColumn.StateExcludes(excludeFilter) &&
                    (dataGridViewColumn.DisplayIndex < dataGridViewColumnStart.DisplayIndex ||
                     (dataGridViewColumn.DisplayIndex == dataGridViewColumnStart.DisplayIndex &&
                      dataGridViewColumn.Index < dataGridViewColumnStart.Index)))
                {
                    if (dataGridViewColumn.DisplayIndex > displayIndexMax ||
                        (dataGridViewColumn.DisplayIndex == displayIndexMax &&
                         dataGridViewColumn.Index > indexMax))
                    {
                        indexMax = index;
                        displayIndexMax = dataGridViewColumn.DisplayIndex;
                        columnFound = true;
                    }
                }
            }
 
            return columnFound ? _items[indexMax] : null;
        }
        else
        {
            index--;
            while (index >= 0)
            {
                DataGridViewColumn dataGridViewColumn = _itemsSorted[index];
                if (dataGridViewColumn.StateIncludes(includeFilter) &&
                    dataGridViewColumn.StateExcludes(excludeFilter))
                {
                    _lastAccessedSortedIndex = index;
                    return dataGridViewColumn;
                }
 
                index--;
            }
        }
 
        return null;
    }
 
    public int IndexOf(DataGridViewColumn dataGridViewColumn) => _items.IndexOf(dataGridViewColumn);
 
    /// <summary>
    ///  Inserts a <see cref="DataGridViewColumn"/> in this collection.
    /// </summary>
    public virtual void Insert(int columnIndex, DataGridViewColumn dataGridViewColumn)
    {
        Debug.Assert(DataGridView is not null);
        if (DataGridView.NoDimensionChangeAllowed)
        {
            throw new InvalidOperationException(SR.DataGridView_ForbiddenOperationInEventHandler);
        }
 
        if (DataGridView.InDisplayIndexAdjustments)
        {
            // We are within columns display indexes adjustments.
            // We do not allow changing the column collection while adjusting display indexes.
            throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
        }
 
        ArgumentNullException.ThrowIfNull(dataGridViewColumn);
 
        int originalDisplayIndex = dataGridViewColumn.DisplayIndex;
        if (originalDisplayIndex == -1)
        {
            dataGridViewColumn.DisplayIndex = columnIndex;
        }
 
        Point newCurrentCell;
        try
        {
            DataGridView.OnInsertingColumn(columnIndex, dataGridViewColumn, out newCurrentCell);   // will throw an exception if the insertion is illegal
        }
        finally
        {
            dataGridViewColumn.DisplayIndexInternal = originalDisplayIndex;
        }
 
        InvalidateCachedColumnsOrder();
        _items.Insert(columnIndex, dataGridViewColumn);
        dataGridViewColumn.Index = columnIndex;
        dataGridViewColumn.DataGridView = DataGridView;
        UpdateColumnCaches(dataGridViewColumn, true);
        DataGridView.OnInsertedColumn_PreNotification(dataGridViewColumn);
        OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Add, dataGridViewColumn), true /*changeIsInsertion*/, newCurrentCell);
#if DEBUG
        Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
    }
 
    internal void InvalidateCachedColumnCount(DataGridViewElementStates includeFilter)
    {
        Debug.Assert(includeFilter is DataGridViewElementStates.Displayed
            or DataGridViewElementStates.Selected
            or DataGridViewElementStates.ReadOnly
            or DataGridViewElementStates.Resizable
            or DataGridViewElementStates.Frozen
            or DataGridViewElementStates.Visible);
 
        if (includeFilter == DataGridViewElementStates.Visible)
        {
            InvalidateCachedColumnCounts();
        }
        else if (includeFilter == DataGridViewElementStates.Selected)
        {
            _columnCountsVisibleSelected = -1;
        }
    }
 
    internal void InvalidateCachedColumnCounts() => _columnCountsVisible = _columnCountsVisibleSelected = -1;
 
    internal void InvalidateCachedColumnsOrder() => _itemsSorted = null;
 
    internal void InvalidateCachedColumnsWidth(DataGridViewElementStates includeFilter)
    {
        Debug.Assert(includeFilter is DataGridViewElementStates.Displayed
            or DataGridViewElementStates.Selected
            or DataGridViewElementStates.ReadOnly
            or DataGridViewElementStates.Resizable
            or DataGridViewElementStates.Frozen
            or DataGridViewElementStates.Visible);
 
        if (includeFilter == DataGridViewElementStates.Visible)
        {
            InvalidateCachedColumnsWidths();
        }
        else if (includeFilter == DataGridViewElementStates.Frozen)
        {
            _columnsWidthVisibleFrozen = -1;
        }
    }
 
    internal void InvalidateCachedColumnsWidths() => _columnsWidthVisible = _columnsWidthVisibleFrozen = -1;
 
    protected virtual void OnCollectionChanged(CollectionChangeEventArgs e) => _onCollectionChanged?.Invoke(this, e);
 
    private void OnCollectionChanged(CollectionChangeEventArgs ccea, bool changeIsInsertion, Point newCurrentCell)
    {
#if DEBUG
        Debug.Assert(VerifyColumnDisplayIndexes());
#endif
        OnCollectionChanged_PreNotification(ccea);
        OnCollectionChanged(ccea);
        OnCollectionChanged_PostNotification(ccea, changeIsInsertion, newCurrentCell);
    }
 
    private void OnCollectionChanged_PreNotification(CollectionChangeEventArgs ccea)
    {
        Debug.Assert(DataGridView is not null);
        DataGridView.OnColumnCollectionChanged_PreNotification(ccea);
    }
 
    private void OnCollectionChanged_PostNotification(CollectionChangeEventArgs ccea, bool changeIsInsertion, Point newCurrentCell)
    {
        Debug.Assert(DataGridView is not null);
        DataGridViewColumn? dataGridViewColumn = (DataGridViewColumn?)ccea.Element;
        if (ccea.Action == CollectionChangeAction.Add && changeIsInsertion)
        {
            DataGridView.OnInsertedColumn_PostNotification(newCurrentCell);
        }
        else if (ccea.Action == CollectionChangeAction.Remove && dataGridViewColumn is not null)
        {
            DataGridView.OnRemovedColumn_PostNotification(dataGridViewColumn, newCurrentCell);
        }
 
        DataGridView.OnColumnCollectionChanged_PostNotification(dataGridViewColumn);
    }
 
    public virtual void Remove(DataGridViewColumn dataGridViewColumn)
    {
        ArgumentNullException.ThrowIfNull(dataGridViewColumn);
 
        if (dataGridViewColumn.DataGridView != DataGridView)
        {
            throw new ArgumentException(SR.DataGridView_ColumnDoesNotBelongToDataGridView, nameof(dataGridViewColumn));
        }
 
        int itemsCount = _items.Count;
        for (int i = 0; i < itemsCount; ++i)
        {
            if (_items[i] == dataGridViewColumn)
            {
                RemoveAt(i);
#if DEBUG
                Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
                return;
            }
        }
 
        Debug.Fail("Column should have been found in DataGridViewColumnCollection.Remove");
    }
 
    public virtual void Remove(string columnName)
    {
        ArgumentNullException.ThrowIfNull(columnName);
 
        int itemsCount = _items.Count;
        for (int i = 0; i < itemsCount; ++i)
        {
            DataGridViewColumn dataGridViewColumn = _items[i];
            // NOTE: case-insensitive
            if (string.Compare(dataGridViewColumn.Name, columnName, true, CultureInfo.InvariantCulture) == 0)
            {
                RemoveAt(i);
                return;
            }
        }
 
        throw new ArgumentException(string.Format(SR.DataGridViewColumnCollection_ColumnNotFound, columnName), nameof(columnName));
    }
 
    public virtual void RemoveAt(int index)
    {
        ArgumentOutOfRangeException.ThrowIfNegative(index);
        ArgumentOutOfRangeException.ThrowIfGreaterThanOrEqual(index, Count);
 
        if (DataGridView.NoDimensionChangeAllowed)
        {
            throw new InvalidOperationException(SR.DataGridView_ForbiddenOperationInEventHandler);
        }
 
        if (DataGridView.InDisplayIndexAdjustments)
        {
            // We are within columns display indexes adjustments.
            // We do not allow changing the column collection while adjusting display indexes.
            throw new InvalidOperationException(SR.DataGridView_CannotAlterDisplayIndexWithinAdjustments);
        }
 
        RemoveAtInternal(index, false /*force*/);
#if DEBUG
        Debug.Assert(_itemsSorted is null || VerifyColumnOrderCache());
#endif
    }
 
    internal void RemoveAtInternal(int index, bool force)
    {
        // If force is true, the underlying data is gone and can't be accessed anymore.
 
        Debug.Assert(index >= 0 && index < Count);
        Debug.Assert(DataGridView is not null);
        Debug.Assert(!DataGridView.NoDimensionChangeAllowed);
        Debug.Assert(!DataGridView.InDisplayIndexAdjustments);
 
        DataGridViewColumn dataGridViewColumn = _items[index];
 
        if (DataGridView.IsAccessibilityObjectCreated && OsVersion.IsWindows8OrGreater())
        {
            foreach (DataGridViewRow row in DataGridView.Rows)
            {
                row.Cells[index].ReleaseUiaProvider();
            }
 
            dataGridViewColumn.HeaderCell.ReleaseUiaProvider();
        }
 
        DataGridView.OnRemovingColumn(dataGridViewColumn, out Point newCurrentCell, force);
        InvalidateCachedColumnsOrder();
        _items.RemoveAt(index);
        dataGridViewColumn.DataGridView = null;
        UpdateColumnCaches(dataGridViewColumn, false);
        DataGridView.OnRemovedColumn_PreNotification(dataGridViewColumn);
        OnCollectionChanged(new CollectionChangeEventArgs(CollectionChangeAction.Remove, dataGridViewColumn), false /*changeIsInsertion*/, newCurrentCell);
    }
 
    private void UpdateColumnCaches(DataGridViewColumn dataGridViewColumn, bool adding)
    {
        if (_columnCountsVisible != -1 || _columnCountsVisibleSelected != -1 ||
            _columnsWidthVisible != -1 || _columnsWidthVisibleFrozen != -1)
        {
            DataGridViewElementStates columnStates = dataGridViewColumn.State;
            if ((columnStates & DataGridViewElementStates.Visible) != 0)
            {
                int columnCountIncrement = adding ? 1 : -1;
                int columnWidthIncrement = 0;
                if (_columnsWidthVisible != -1 ||
                    (_columnsWidthVisibleFrozen != -1 &&
                     ((columnStates & (DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen)) == (DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen))))
                {
                    columnWidthIncrement = adding ? dataGridViewColumn.Width : -dataGridViewColumn.Width;
                }
 
                if (_columnCountsVisible != -1)
                {
                    _columnCountsVisible += columnCountIncrement;
                }
 
                if (_columnsWidthVisible != -1)
                {
                    Debug.Assert(columnWidthIncrement != 0);
                    _columnsWidthVisible += columnWidthIncrement;
                }
 
                if ((columnStates & (DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen)) == (DataGridViewElementStates.Visible | DataGridViewElementStates.Frozen))
                {
                    if (_columnsWidthVisibleFrozen != -1)
                    {
                        Debug.Assert(columnWidthIncrement != 0);
                        _columnsWidthVisibleFrozen += columnWidthIncrement;
                    }
                }
 
                if ((columnStates & (DataGridViewElementStates.Visible | DataGridViewElementStates.Selected)) == (DataGridViewElementStates.Visible | DataGridViewElementStates.Selected))
                {
                    if (_columnCountsVisibleSelected != -1)
                    {
                        _columnCountsVisibleSelected += columnCountIncrement;
                    }
                }
            }
        }
    }
 
    [MemberNotNull(nameof(_itemsSorted))]
    private void UpdateColumnOrderCache()
    {
        _itemsSorted = [.. _items];
        _itemsSorted.Sort(s_columnOrderComparer);
        _lastAccessedSortedIndex = -1;
    }
 
#if DEBUG
    internal bool VerifyColumnDisplayIndexes()
    {
        for (int columnDisplayIndex = 0; columnDisplayIndex < _items.Count; columnDisplayIndex++)
        {
            if (GetColumnAtDisplayIndex(columnDisplayIndex) is null)
            {
                return false;
            }
        }
 
        return true;
    }
 
    private bool VerifyColumnOrderCache()
    {
        if (_itemsSorted is null)
        {
            return false;
        }
 
        if (_itemsSorted.Count != _items.Count)
        {
            return false;
        }
 
        int index = 0;
        while (index < _itemsSorted.Count - 1)
        {
            if (_itemsSorted[index + 1].DisplayIndex !=
                _itemsSorted[index].DisplayIndex + 1)
            {
                return false;
            }
 
            index++;
        }
 
        return true;
    }
#endif
 
}