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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* This software is subject to the Microsoft Public License (Ms-PL).
* A copy of the license can be found in the license.htm file included
* in this distribution.
*
* You must not remove this notice, or any other, from this software.
*
* ***************************************************************************/
namespace System.Web.Mvc {
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Web.UI;
[SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
[SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Multi",
Justification = "Common shorthand for 'multiple'.")]
public class MultiSelectList : IEnumerable<SelectListItem> {
public MultiSelectList(IEnumerable items)
: this(items, null /* selectedValues */) {
}
public MultiSelectList(IEnumerable items, IEnumerable selectedValues)
: this(items, null /* dataValuefield */, null /* dataTextField */, selectedValues) {
}
public MultiSelectList(IEnumerable items, string dataValueField, string dataTextField)
: this(items, dataValueField, dataTextField, null /* selectedValues */) {
}
public MultiSelectList(IEnumerable items, string dataValueField, string dataTextField, IEnumerable selectedValues) {
if (items == null) {
throw new ArgumentNullException("items");
}
Items = items;
DataValueField = dataValueField;
DataTextField = dataTextField;
SelectedValues = selectedValues;
}
public string DataTextField {
get;
private set;
}
public string DataValueField {
get;
private set;
}
public IEnumerable Items {
get;
private set;
}
public IEnumerable SelectedValues {
get;
private set;
}
public virtual IEnumerator<SelectListItem> GetEnumerator() {
return GetListItems().GetEnumerator();
}
[SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate",
Justification = "Operation performs conversions and returns a unique instance on each call.")]
internal IList<SelectListItem> GetListItems() {
return (!String.IsNullOrEmpty(DataValueField)) ?
GetListItemsWithValueField() :
GetListItemsWithoutValueField();
}
private IList<SelectListItem> GetListItemsWithValueField() {
HashSet<string> selectedValues = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
if (SelectedValues != null) {
selectedValues.UnionWith(from object value in SelectedValues select Convert.ToString(value, CultureInfo.CurrentCulture));
}
var listItems = from object item in Items
let value = Eval(item, DataValueField)
select new SelectListItem {
Value = value,
Text = Eval(item, DataTextField),
Selected = selectedValues.Contains(value)
};
return listItems.ToList();
}
private IList<SelectListItem> GetListItemsWithoutValueField() {
HashSet<object> selectedValues = new HashSet<object>();
if (SelectedValues != null) {
selectedValues.UnionWith(SelectedValues.Cast<object>());
}
var listItems = from object item in Items
select new SelectListItem {
Text = Eval(item, DataTextField),
Selected = selectedValues.Contains(item)
};
return listItems.ToList();
}
private static string Eval(object container, string expression) {
object value = container;
if (!String.IsNullOrEmpty(expression)) {
value = DataBinder.Eval(container, expression);
}
return Convert.ToString(value, CultureInfo.CurrentCulture);
}
#region IEnumerable Members
IEnumerator IEnumerable.GetEnumerator() {
return GetEnumerator();
}
#endregion
}
}
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