ComboBox.ComboBoxItemAccessibleObjectTests.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Drawing;
using System.Windows.Forms.IntegrationTests.Common;
using Windows.Win32.System.Variant;
using Windows.Win32.UI.Accessibility;
using static System.Windows.Forms.ComboBox;
using static System.Windows.Forms.ComboBox.ObjectCollection;
 
namespace System.Windows.Forms.Tests.AccessibleObjects;
 
public class ComboBox_ComboBoxItemAccessibleObjectTests
{
    private const AccessibleStates InvisibleItemState = AccessibleStates.Invisible | AccessibleStates.Offscreen | AccessibleStates.Focusable | AccessibleStates.Selectable;
    private const AccessibleStates VisibleItemState = AccessibleStates.Selected | AccessibleStates.Focusable | AccessibleStates.Selectable;
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_Get_Not_ThrowsException()
    {
        using (new NoAssertContext())
        {
            using ComboBox control = new();
 
            HashNotImplementedObject item1 = new();
            HashNotImplementedObject item2 = new();
            HashNotImplementedObject item3 = new();
 
            control.Items.AddRange(new[] { item1, item2, item3 });
 
            ComboBox.ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBox.ComboBoxAccessibleObject)control.AccessibilityObject;
 
            bool exceptionThrown = false;
 
            try
            {
                ComboBox.ComboBoxItemAccessibleObject item1AccessibleObject = comboBoxAccessibleObject.ItemAccessibleObjects.GetComboBoxItemAccessibleObject(control.Items.InnerList[0]);
                ComboBox.ComboBoxItemAccessibleObject item2AccessibleObject = comboBoxAccessibleObject.ItemAccessibleObjects.GetComboBoxItemAccessibleObject(control.Items.InnerList[1]);
                ComboBox.ComboBoxItemAccessibleObject item3AccessibleObject = comboBoxAccessibleObject.ItemAccessibleObjects.GetComboBoxItemAccessibleObject(control.Items.InnerList[2]);
            }
            catch
            {
                exceptionThrown = true;
            }
 
            Assert.False(exceptionThrown, "Getting accessible object for ComboBox item has thrown an exception.");
        }
    }
 
    public class HashNotImplementedObject
    {
        public override int GetHashCode()
        {
            throw new NotImplementedException();
        }
    }
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_DataBoundAccessibleName()
    {
        using (new NoAssertContext())
        {
            // Regression test for https://github.com/dotnet/winforms/issues/3549
            using ComboBox control = new()
            {
                DataSource = TestDataSources.GetPersons(),
                DisplayMember = TestDataSources.PersonDisplayMember
            };
 
            ComboBox.ComboBoxAccessibleObject accessibleObject = Assert.IsType<ComboBox.ComboBoxAccessibleObject>(control.AccessibilityObject);
 
            foreach (Person person in TestDataSources.GetPersons())
            {
                ComboBox.ComboBoxItemAccessibleObject item = accessibleObject.ItemAccessibleObjects.GetComboBoxItemAccessibleObject(new Entry(person));
                AccessibleObject itemAccessibleObject = Assert.IsType<ComboBox.ComboBoxItemAccessibleObject>(item);
                Assert.Equal(person.Name, itemAccessibleObject.Name);
            }
        }
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDown)]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.Simple)]
    public void ComboBoxItemAccessibleObject_SeveralSameItems_FragmentNavigate_NextSibling_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = new ComboBox
        {
            DropDownStyle = comboBoxStyle
        };
 
        comboBox.Items.AddRange(new[] { "aaa", "aaa", "aaa" });
        comboBox.CreateControl();
 
        ComboBoxItemAccessibleObjectCollection itemAccessibleObjects = ((ComboBox.ComboBoxAccessibleObject)comboBox.AccessibilityObject).ItemAccessibleObjects;
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
            .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        Assert.Equal("aaa", comboBoxItem1.Name);
        Assert.Equal(comboBoxItem1, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[0]));
 
        // FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling) should return accessible object for second "aaa" item
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
            .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        Assert.NotEqual(comboBoxItem1, comboBoxItem2);
        Assert.Equal("aaa", comboBoxItem2.Name);
        Assert.Equal(comboBoxItem2, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[1]));
 
        // FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling) should return accessible object for third "aaa" item
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
            .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        Assert.NotEqual(comboBoxItem3, comboBoxItem2);
        Assert.NotEqual(comboBoxItem3, comboBoxItem1);
        Assert.Equal("aaa", comboBoxItem3.Name);
        Assert.Equal(comboBoxItem3, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[2]));
 
        Assert.True(comboBox.IsHandleCreated);
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDown)]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.Simple)]
    public void ComboBoxItemAccessibleObject_SeveralSameItems_FragmentNavigate_PreviousSibling_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = new ComboBox
        {
            DropDownStyle = comboBoxStyle
        };
 
        comboBox.Items.AddRange(new[] { "aaa", "aaa", "aaa" });
        comboBox.CreateControl();
 
        ComboBoxItemAccessibleObjectCollection itemAccessibleObjects = ((ComboBox.ComboBoxAccessibleObject)comboBox.AccessibilityObject).ItemAccessibleObjects;
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
            .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_LastChild);
 
        Assert.Equal("aaa", comboBoxItem3.Name);
        Assert.Equal(comboBoxItem3, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[2]));
 
        // FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling) should return accessible object for second "aaa" item
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem3
            .FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling);
 
        Assert.NotEqual(comboBoxItem2, comboBoxItem3);
        Assert.Equal("aaa", comboBoxItem2.Name);
        Assert.Equal(comboBoxItem2, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[1]));
 
        // FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling) should return accessible object for first "aaa" item
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
            .FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling);
        Assert.NotEqual(comboBoxItem1, comboBoxItem2);
        Assert.NotEqual(comboBoxItem1, comboBoxItem3);
        Assert.Equal("aaa", comboBoxItem1.Name);
        Assert.Equal(comboBoxItem1, itemAccessibleObjects.GetComboBoxItemAccessibleObject(comboBox.Items.InnerList[0]));
 
        // FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling) should return null for first "aaa" item
        ComboBox.ComboBoxItemAccessibleObject comboBoxItemPrevious = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
            .FragmentNavigate(NavigateDirection.NavigateDirection_PreviousSibling);
        Assert.Null(comboBoxItemPrevious);
        Assert.True(comboBox.IsHandleCreated);
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDown)]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.Simple)]
    public void ComboBoxItemAccessibleObject_FragmentNavigate_Parent_ReturnListAccessibleObject(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBox(comboBoxStyle);
        AccessibleObject childListAccessibleObject = comboBox.ChildListAccessibleObject;
        AccessibleObject comboBoxItem = (AccessibleObject)childListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
 
        Assert.Equal(childListAccessibleObject, comboBoxItem.FragmentNavigate(NavigateDirection.NavigateDirection_Parent));
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDown)]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.Simple)]
    public void ComboBoxItemAccessibleObject_FragmentNavigate_Child_ReturnNull(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBox(comboBoxStyle);
        AccessibleObject childListAccessibleObject = comboBox.ChildListAccessibleObject;
        AccessibleObject comboBoxItem = (AccessibleObject)childListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
 
        Assert.Null(comboBoxItem.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild));
        Assert.Null(comboBoxItem.FragmentNavigate(NavigateDirection.NavigateDirection_LastChild));
    }
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_IsPatternSupported_ReturnsTrue_ForScrollItemPattern()
    {
        using ComboBox comboBox = new();
        comboBox.Items.AddRange(new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" });
        comboBox.CreateControl();
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
 
        // Check that all items support ScrollItemPattern
        foreach (Entry itemEntry in comboBox.Items.InnerList)
        {
            ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
 
            Assert.True(itemAccessibleObject.IsPatternSupported(UIA_PATTERN_ID.UIA_ScrollItemPatternId));
        }
    }
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_GetPropertyValue_Pattern_IsAvailable()
    {
        using ComboBox comboBox = new();
        comboBox.Items.AddRange(new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" });
        comboBox.CreateControl();
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
 
        // Check that all items support Pattern
        foreach (Entry itemEntry in comboBox.Items.InnerList)
        {
            ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
 
            Assert.True((bool)itemAccessibleObject.GetPropertyValue(UIA_PROPERTY_ID.UIA_IsScrollItemPatternAvailablePropertyId));
            Assert.True((bool)itemAccessibleObject.GetPropertyValue(UIA_PROPERTY_ID.UIA_IsSelectionItemPatternAvailablePropertyId));
            Assert.Equal(VARIANT.Empty, itemAccessibleObject.GetPropertyValue(UIA_PROPERTY_ID.UIA_ValueValuePropertyId));
        }
    }
 
    public static IEnumerable<object[]> ComboBoxItemAccessibleObject_ScrollIntoView_DoNothing_IfControlIsNotEnabled_TestData()
    {
        foreach (ComboBoxStyle comboBoxStyle in Enum.GetValues(typeof(ComboBoxStyle)))
        {
            yield return new object[] { comboBoxStyle };
        }
    }
 
    [WinFormsTheory]
    [MemberData(nameof(ComboBoxItemAccessibleObject_ScrollIntoView_DoNothing_IfControlIsNotEnabled_TestData))]
    public void ComboBoxItemAccessibleObject_ScrollIntoView_DoNothing_IfControlIsNotEnabled(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = new();
        comboBox.IntegralHeight = false;
        comboBox.DropDownStyle = comboBoxStyle;
        comboBox.Enabled = false;
        comboBox.Items.AddRange(new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" });
        comboBox.CreateControl();
 
        if (comboBoxStyle == ComboBoxStyle.Simple)
        {
            comboBox.Size = new Size(100, 132);
        }
        else
        {
            comboBox.DropDownHeight = 107;
            comboBox.DroppedDown = true;
        }
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
        Entry itemEntry = comboBox.Items.InnerList[10];
        ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
 
        itemAccessibleObject.ScrollIntoView();
 
        int actual = (int)PInvoke.SendMessage(comboBox, PInvoke.CB_GETTOPINDEX);
 
        Assert.Equal(0, actual); // ScrollIntoView didn't scroll to the tested item because the ComboBox is disabled
    }
 
    public static IEnumerable<object[]> ComboBoxItemAccessibleObject_ScrollIntoView_EnsureVisible_TestData()
    {
        foreach (bool scrollingDown in new[] { true, false })
        {
            foreach (ComboBoxStyle comboBoxStyle in Enum.GetValues(typeof(ComboBoxStyle)))
            {
                int itemsCount = 41;
 
                for (int index = 0; index < itemsCount; index += 10)
                {
                    yield return new object[] { comboBoxStyle, scrollingDown, index, itemsCount };
                }
            }
        }
    }
 
    [WinFormsTheory]
    [MemberData(nameof(ComboBoxItemAccessibleObject_ScrollIntoView_EnsureVisible_TestData))]
    public void ComboBoxItemAccessibleObject_ScrollIntoView_EnsureVisible(ComboBoxStyle comboBoxStyle, bool scrollingDown, int itemIndex, int itemsCount)
    {
        using ComboBox comboBox = new();
        comboBox.IntegralHeight = false;
        comboBox.DropDownStyle = comboBoxStyle;
        comboBox.CreateControl();
 
        for (int i = 0; i < itemsCount; i++)
        {
            comboBox.Items.Add(i);
        }
 
        if (comboBoxStyle == ComboBoxStyle.Simple)
        {
            comboBox.Size = new Size(100, 132);
        }
        else
        {
            comboBox.DropDownHeight = 107;
            comboBox.DroppedDown = true;
        }
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
        Entry itemEntry = comboBox.Items.InnerList[itemIndex];
        ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
 
        int expected;
        Rectangle dropDownRect = comboBox.ChildListAccessibleObject.Bounds;
        int visibleItemsCount = (int)Math.Ceiling((double)dropDownRect.Height / comboBox.ItemHeight);
 
        // Get an index of the first item that is visible if dropdown is scrolled to the bottom
        int lastFirstVisible = itemsCount - visibleItemsCount;
 
        if (scrollingDown)
        {
            if (dropDownRect.IntersectsWith(itemAccessibleObject.Bounds))
            {
                // ScrollIntoView method shouldn't scroll to the item because it is already visible
                expected = 0;
            }
            else
            {
                // ScrollIntoView method should scroll to the item or
                //  the first item that is visible if dropdown is scrolled to the bottom
                expected = itemIndex > lastFirstVisible ? lastFirstVisible : itemIndex;
            }
        }
        else
        {
            // Scroll to the bottom and test the method when scrolling up
            PInvoke.SendMessage(comboBox, PInvoke.CB_SETTOPINDEX, (WPARAM)(itemsCount - 1));
 
            if (dropDownRect.IntersectsWith(itemAccessibleObject.Bounds))
            {
                // ScrollIntoView method shouldn't scroll to the item because it is already visible
                expected = lastFirstVisible;
            }
            else
            {
                // ScrollIntoView method should scroll to the item
                expected = itemIndex;
            }
        }
 
        itemAccessibleObject.ScrollIntoView();
 
        int actual = (int)PInvoke.SendMessage(comboBox, PInvoke.CB_GETTOPINDEX);
 
        Assert.Equal(expected, actual);
    }
 
    public static IEnumerable<object[]> ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_IfComboBoxIsScrollable_TestData()
    {
        foreach (ComboBoxStyle comboBoxStyle in Enum.GetValues(typeof(ComboBoxStyle)))
        {
            // The tested ComboBox contains 11 items
            for (int index = 0; index < 11; index++)
            {
                int y = index * 15;
                int initialYPosition = comboBoxStyle == ComboBoxStyle.Simple ? 56 : 55;
                int x = comboBoxStyle == ComboBoxStyle.Simple ? 10 : 9;
                Point point = new(x, y + initialYPosition);
 
                yield return new object[] { comboBoxStyle, index, point };
            }
        }
    }
 
    [WinFormsTheory]
    [MemberData(nameof(ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_IfComboBoxIsScrollable_TestData))]
    public void ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_IfComboBoxIsScrollable(ComboBoxStyle comboBoxStyle, int itemIndex, Point expectedPosition)
    {
        using ComboBox comboBox = new();
        comboBox.IntegralHeight = false;
        comboBox.DropDownStyle = comboBoxStyle;
        comboBox.Items.AddRange(new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" });
        comboBox.CreateControl();
 
        if (comboBoxStyle == ComboBoxStyle.Simple)
        {
            comboBox.Size = new Size(100, 132);
        }
        else
        {
            comboBox.Size = new Size(100, comboBox.Size.Height);
            comboBox.DropDownHeight = 105;
            comboBox.DroppedDown = true;
        }
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
        Entry itemEntry = comboBox.Items.InnerList[itemIndex];
        ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
        Rectangle actual = itemAccessibleObject.Bounds;
        Rectangle dropdownRect = comboBox.ChildListAccessibleObject.Bounds;
 
        // We get items rectangles from Windows
        // It returns to us different expected widths values depending on a ComboBox drop-down style
        int itemWidth = comboBoxStyle == ComboBoxStyle.Simple ? 79 : 81;
 
        Assert.Equal(expectedPosition.X, actual.X);
        Assert.Equal(expectedPosition.Y, actual.Y);
        Assert.Equal(itemWidth, actual.Width); // All items are the same width
        Assert.Equal(15, actual.Height); // All items are the same height
    }
 
    public static IEnumerable<object[]> ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_ForDifferentHeightItems_TestData()
    {
        foreach (ComboBoxStyle comboBoxStyle in Enum.GetValues(typeof(ComboBoxStyle)))
        {
            // The tested ComboBox contains 11 items
            for (int index = 0; index < 11; index++)
            {
                int height = DifferentHeightComboBox.GetCustomItemHeight(index);
 
                // We get items rectangles from Windows
                // It returns to us different expected bounds values depending on a ComboBox drop-down style
                int width = comboBoxStyle == ComboBoxStyle.Simple ? 96 : 81;
                int x = comboBoxStyle == ComboBoxStyle.Simple ? 10 : 9;
                int y = comboBoxStyle == ComboBoxStyle.Simple ? 57 : 56;
 
                for (int i = 0; i < index; i++)
                {
                    y += DifferentHeightComboBox.GetCustomItemHeight(i); // Calculate the sum of heights of all items before the current
                }
 
                yield return new object[] { comboBoxStyle, index, new Rectangle(x, y, width, height) };
            }
        }
    }
 
    [WinFormsTheory]
    [MemberData(nameof(ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_ForDifferentHeightItems_TestData))]
    public void ComboBoxItemAccessibleObject_Bounds_ReturnsCorrect_ForDifferentHeightItems(ComboBoxStyle comboBoxStyle, int itemIndex, Rectangle expectedRect)
    {
        using DifferentHeightComboBox comboBox = new();
        comboBox.DropDownStyle = comboBoxStyle;
        comboBox.Items.AddRange(new[] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" });
        comboBox.CreateControl();
 
        if (comboBoxStyle == ComboBoxStyle.Simple)
        {
            comboBox.Size = new Size(100, 400);
        }
        else
        {
            comboBox.Size = new Size(100, comboBox.Size.Height);
            comboBox.DropDownHeight = 400;
            comboBox.DroppedDown = true;
        }
 
        ComboBoxAccessibleObject comboBoxAccessibleObject = (ComboBoxAccessibleObject)comboBox.AccessibilityObject;
        ComboBoxItemAccessibleObjectCollection itemsCollection = comboBoxAccessibleObject.ItemAccessibleObjects;
        Entry itemEntry = comboBox.Items.InnerList[itemIndex];
        ComboBoxItemAccessibleObject itemAccessibleObject = itemsCollection.GetComboBoxItemAccessibleObject(itemEntry);
        Rectangle actual = itemAccessibleObject.Bounds;
        Rectangle dropdownRect = comboBox.ChildListAccessibleObject.Bounds;
 
        Assert.Equal(expectedRect, actual);
    }
 
    private class DifferentHeightComboBox : ComboBox
    {
        public DifferentHeightComboBox() : base()
        {
            DrawMode = DrawMode.OwnerDrawVariable;
        }
 
        public static int GetCustomItemHeight(int index) => 15 + (index % 5) * 5;
 
        protected override void OnMeasureItem(MeasureItemEventArgs e)
        {
            e.ItemHeight = GetCustomItemHeight(e.Index);
            base.OnMeasureItem(e);
        }
 
        protected override void OnDrawItem(DrawItemEventArgs e)
        {
            if (e.Index < 0 || e.Index >= Items.Count)
            {
                return;
            }
 
            e.DrawBackground();
            using SolidBrush brush = new(e.ForeColor);
            e.Graphics.DrawString(
                Items[e.Index].ToString(),
                e.Font,
                brush,
                e.Bounds);
            e.DrawFocusRectangle();
            base.OnDrawItem(e);
        }
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_MaxDropDownItems_State_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBoxWithMaxItems(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        Assert.Equal(InvisibleItemState, comboBoxItem1.State); // comboBoxItem1 above the visible area
        Assert.Equal(VisibleItemState, comboBoxItem2.State); // comboBoxItem2 in the visible area
        Assert.Equal(InvisibleItemState, comboBoxItem3.State); // comboBoxItem3 below the visible area
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_DropDownHeight_State_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBoxWithMaxHeight(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        Assert.Equal(InvisibleItemState, comboBoxItem1.State); // comboBoxItem1 above the visible area
        Assert.Equal(VisibleItemState, comboBoxItem2.State); // comboBoxItem2 in the visible area
        Assert.Equal(InvisibleItemState, comboBoxItem3.State); // comboBoxItem3 below the visible area
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_DropDownCollapsed_State_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBox(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        Assert.Equal(InvisibleItemState, comboBoxItem1.State);
        Assert.Equal(InvisibleItemState, comboBoxItem2.State);
    }
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_State_ReturnExpected()
    {
        using ComboBox comboBox = GetComboBoxWithMaxSize(ComboBoxStyle.Simple);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        AccessibleStates itemState = AccessibleStates.Invisible | AccessibleStates.Selected | AccessibleStates.Focusable | AccessibleStates.Selectable;
 
        Assert.Equal(InvisibleItemState, comboBoxItem1.State); // comboBoxItem1 above the visible area
        Assert.Equal(itemState, comboBoxItem2.State); // comboBoxItem2 in the visible area
        Assert.Equal(InvisibleItemState, comboBoxItem3.State); // comboBoxItem3 below the visible area
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_MaxDropDownItems_GetOffScreenProperty_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBoxWithMaxItems(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        AssertExtensions.True(comboBoxItem1, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem1 above the visible area
        AssertExtensions.False(comboBoxItem2, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem2 in the visible area
        AssertExtensions.True(comboBoxItem3, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem3 below the visible area
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_DropDownHeight_GetOffScreenProperty_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBoxWithMaxHeight(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        AssertExtensions.True(comboBoxItem1, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem1 above the visible area
        AssertExtensions.False(comboBoxItem2, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem2 in the visible area
        AssertExtensions.True(comboBoxItem3, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem3 below the visible area
    }
 
    [WinFormsTheory]
    [InlineData(ComboBoxStyle.DropDownList)]
    [InlineData(ComboBoxStyle.DropDown)]
    public void ComboBoxItemAccessibleObject_DropDownCollapsed_GetOffScreenProperty_ReturnExpected(ComboBoxStyle comboBoxStyle)
    {
        using ComboBox comboBox = GetComboBox(comboBoxStyle);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        AssertExtensions.True(comboBoxItem1, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId);
        AssertExtensions.True(comboBoxItem2, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId);
    }
 
    [WinFormsFact]
    public void ComboBoxItemAccessibleObject_GetOffScreenProperty_ReturnExpected()
    {
        using ComboBox comboBox = GetComboBoxWithMaxSize(ComboBoxStyle.Simple);
 
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem1 = (ComboBox.ComboBoxItemAccessibleObject)comboBox
                .ChildListAccessibleObject.FragmentNavigate(NavigateDirection.NavigateDirection_FirstChild);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem2 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem1
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
        ComboBox.ComboBoxItemAccessibleObject comboBoxItem3 = (ComboBox.ComboBoxItemAccessibleObject)comboBoxItem2
                .FragmentNavigate(NavigateDirection.NavigateDirection_NextSibling);
 
        AssertExtensions.True(comboBoxItem1, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem1 above the visible area
        AssertExtensions.False(comboBoxItem2, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem2 in the visible area
        AssertExtensions.True(comboBoxItem3, UIA_PROPERTY_ID.UIA_IsOffscreenPropertyId); // comboBoxItem3 below the visible area
    }
 
    private ComboBox GetComboBox(ComboBoxStyle comboBoxStyle)
    {
        ComboBox comboBox = new ComboBox
        {
            DropDownStyle = comboBoxStyle
        };
 
        comboBox.Items.Add(1);
        comboBox.Items.Add(2);
        comboBox.Items.Add(3);
        comboBox.CreateControl();
        return comboBox;
    }
 
    private ComboBox GetComboBoxWithMaxItems(ComboBoxStyle comboBoxStyle)
    {
        ComboBox comboBox = GetComboBox(comboBoxStyle);
        comboBox.IntegralHeight = false;
        comboBox.MaxDropDownItems = 1;
        comboBox.SelectedIndex = 1;
        comboBox.DroppedDown = true;
        return comboBox;
    }
 
    private ComboBox GetComboBoxWithMaxHeight(ComboBoxStyle comboBoxStyle)
    {
        ComboBox comboBox = GetComboBox(comboBoxStyle);
        comboBox.DropDownHeight = 10;
        comboBox.SelectedIndex = 1;
        comboBox.DroppedDown = true;
        return comboBox;
    }
 
    private ComboBox GetComboBoxWithMaxSize(ComboBoxStyle comboBoxStyle)
    {
        ComboBox comboBox = GetComboBox(comboBoxStyle);
        comboBox.Size = new Size(100, 50);
        comboBox.SelectedIndex = 1;
        return comboBox;
    }
}
File: System\Windows\Forms\AccessibleObjects\ComboBox.ComboBoxItemAccessibleObjectTests.cs	Web Access
Project: src\src\System.Windows.Forms\tests\UnitTests\System.Windows.Forms.Tests.csproj (System.Windows.Forms.Tests)