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// 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;
namespace Microsoft.AspNetCore.Mvc.Rendering;
/// <summary>
/// Represents a list that lets users select a single item.
/// This class is typically rendered as an HTML <c><select></c> element with the specified collection
/// of <see cref="SelectListItem"/> objects.
/// </summary>
public class SelectList : MultiSelectList
{
/// <summary>
/// Initialize a new instance of <see cref="SelectList"/>.
/// </summary>
/// <param name="items">The items.</param>
public SelectList(IEnumerable items)
: this(items, selectedValue: null)
{
ArgumentNullException.ThrowIfNull(items);
}
/// <summary>
/// Initialize a new instance of <see cref="SelectList"/>.
/// </summary>
/// <param name="items">The items.</param>
/// <param name="selectedValue">The selected value.</param>
public SelectList(IEnumerable items, object selectedValue)
: this(items, dataValueField: null, dataTextField: null, selectedValue: selectedValue)
{
ArgumentNullException.ThrowIfNull(items);
}
/// <summary>
/// Initialize a new instance of <see cref="SelectList"/>.
/// </summary>
/// <param name="items">The items.</param>
/// <param name="dataValueField">The data value field.</param>
/// <param name="dataTextField">The data text field.</param>
public SelectList(IEnumerable items, string dataValueField, string dataTextField)
: this(items, dataValueField, dataTextField, selectedValue: null)
{
ArgumentNullException.ThrowIfNull(items);
}
/// <summary>
/// Initialize a new instance of <see cref="SelectList"/>.
/// </summary>
/// <param name="items">The items.</param>
/// <param name="dataValueField">The data value field.</param>
/// <param name="dataTextField">The data text field.</param>
/// <param name="selectedValue">The selected value.</param>
public SelectList(
IEnumerable items,
string dataValueField,
string dataTextField,
object selectedValue)
: base(items, dataValueField, dataTextField, ToEnumerable(selectedValue))
{
ArgumentNullException.ThrowIfNull(items);
SelectedValue = selectedValue;
}
/// <summary>
/// Initializes a new instance of the SelectList class by using the specified items for the list,
/// the data value field, the data text field, a selected value, and the data group field.
/// </summary>
/// <param name="items">The items used to build each <see cref="SelectListItem"/> of the list.</param>
/// <param name="dataValueField">The data value field. Used to match the Value property of the corresponding
/// <see cref="SelectListItem"/>.</param>
/// <param name="dataTextField">The data text field. Used to match the Text property of the corresponding
/// <see cref="SelectListItem"/>.</param>
/// <param name="selectedValue">The selected values. Used to match the Selected property of the corresponding
/// <see cref="SelectListItem"/>.</param>
/// <param name="dataGroupField">The data group field. Used to match the Group property of the corresponding
/// <see cref="SelectListItem"/>.</param>
public SelectList(
IEnumerable items,
string dataValueField,
string dataTextField,
object selectedValue,
string dataGroupField)
: base(items, dataValueField, dataTextField, ToEnumerable(selectedValue), dataGroupField)
{
ArgumentNullException.ThrowIfNull(items);
SelectedValue = selectedValue;
}
/// <summary>
/// The selected value.
/// </summary>
public object SelectedValue { get; }
private static IEnumerable ToEnumerable(object selectedValue)
{
return (selectedValue != null) ? new[] { selectedValue } : null;
}
}
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