我有一個 ListView，我想改變行為，所以SelectionChanged事件會在 MouseUp 而不是 MouseDown 上觸發。我想改變行為的原因是，當我想拖動物件（在 MouseMove 上）時，當我在要移動的物件上單擊（MouseDown）時，選擇會改變。
我找到了那段代碼，但這僅適用于簡單的選擇，我想允許選擇多個專案。
public static class SelectorBehavior
{
#region bool ShouldSelectItemOnMouseUp
public static readonly DependencyProperty ShouldSelectItemOnMouseUpProperty =
DependencyProperty.RegisterAttached(
"ShouldSelectItemOnMouseUp", typeof(bool), typeof(SelectorBehavior),
new PropertyMetadata(default(bool), HandleShouldSelectItemOnMouseUpChange));
public static void SetShouldSelectItemOnMouseUp(DependencyObject element, bool value)
{
element.SetValue(ShouldSelectItemOnMouseUpProperty, value);
}
public static bool GetShouldSelectItemOnMouseUp(DependencyObject element)
{
return (bool)element.GetValue(ShouldSelectItemOnMouseUpProperty);
}
private static void HandleShouldSelectItemOnMouseUpChange(
DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (d is Selector selector)
{
selector.PreviewMouseDown -= HandleSelectPreviewMouseDown;
selector.MouseUp -= HandleSelectMouseUp;
if (Equals(e.NewValue, true))
{
selector.PreviewMouseDown = HandleSelectPreviewMouseDown;
selector.MouseUp = HandleSelectMouseUp;
}
}
}
private static void HandleSelectMouseUp(object sender, MouseButtonEventArgs e)
{
var selector = (Selector)sender;
if (e.ChangedButton == MouseButton.Left && e.OriginalSource is Visual source)
{
var container = selector.ContainerFromElement(source);
if (container != null)
{
var index = selector.ItemContainerGenerator.IndexFromContainer(container);
if (index >= 0)
{
selector.SelectedIndex = index;
}
}
}
}
private static void HandleSelectPreviewMouseDown(object sender, MouseButtonEventArgs e)
{
e.Handled = e.ChangedButton == MouseButton.Left;
}
#endregion
}
這是我的 Xaml：
<ListView x:Name="ListViewContract" SelectedItem="{Binding SelectedContract}" ItemsSource="{Binding ListContractsView}" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="4" MouseDoubleClick="ListViewContract_DoubleClick" GridViewColumnHeader.Click ="GridViewHeaderClicked" SelectionChanged="ListViewContract_SelectionChanged" Visibility="{Binding Grid1Visible, Converter={StaticResource BoolToVisConverter}}"
MouseMove="ListViewContract_MouseMove" local:SelectorBehavior.ShouldSelectItemOnMouseUp="True">
<ListView.View>
<GridView AllowsColumnReorder="true" x:Name="GridViewContract">
<GridViewColumn DisplayMemberBinding="{Binding ID}" Header="ID" Width="{Binding WidthIDs, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Name}" Header="{x:Static p:Resources.Name}" Width="{Binding WidthColumnContractName, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Code}" Header="{x:Static p:Resources.Number}" Width="{Binding WidthColumnContractCode, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Comm}" Header="{x:Static p:Resources.Commentary}" Width="{Binding WidthColumnContractComm, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Revision}" Header="{x:Static p:Resources.Revision}" Width="{Binding WidthColumnContractRev, Mode=TwoWay}"/>
<GridViewColumn Header="{x:Static p:Resources.Advancement}" Width="{Binding WidthColumnContractAdv, Mode=TwoWay}">
<GridViewColumn.CellTemplate>
<DataTemplate>
<StackPanel>
<Rectangle Name="AFF_Track" Height="12" Stroke="black" StrokeThickness="1" Fill="{Binding RectangleProgression}" Tag="{Binding ID}" MouseMove="mouseOverProgressionContractAss">
<Rectangle.ToolTip>
<ContentControl Template="{StaticResource ToolTipOperations}"/>
</Rectangle.ToolTip>
</Rectangle>
<Rectangle Name="AFF_Track2" Height="12" Stroke="black" StrokeThickness="1" Fill="{Binding RectangleProgressionWeight}" Tag="{Binding ID}" MouseMove="mouseOverProgressionContractAss">
<Rectangle.ToolTip>
<ContentControl Template="{StaticResource ToolTipOperations}"/>
</Rectangle.ToolTip>
</Rectangle>
</StackPanel>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
<GridViewColumn Header="{x:Static p:Resources.Advancement}" Width="{Binding WidthColumnContractAdvRep, Mode=TwoWay}">
<GridViewColumn.CellTemplate>
<DataTemplate>
<StackPanel>
<Rectangle Name="AFF_TrackRep" Height="12" Stroke="black" StrokeThickness="1" Fill="{Binding RectangleProgressionRep}" Tag="{Binding ID}" MouseMove="mouseOverProgressionContractRep">
<Rectangle.ToolTip>
<ContentControl Template="{StaticResource ToolTipOperations}"/>
</Rectangle.ToolTip>
</Rectangle>
<Rectangle Name="AFF_Track2Rep" Height="12" Stroke="black" StrokeThickness="1" Fill="{Binding RectangleProgressionRepWeight}" Tag="{Binding ID}" MouseMove="mouseOverProgressionContractRep">
<Rectangle.ToolTip>
<ContentControl Template="{StaticResource ToolTipOperations}"/>
</Rectangle.ToolTip>
</Rectangle>
</StackPanel>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
<GridViewColumn DisplayMemberBinding="{Binding Manager.CompleteName}" Header="{x:Static p:Resources.ProjectManager}" Width="{Binding WidthColumnContractManager, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Client.Name}" Header="{x:Static p:Resources.Customer}" Width="{Binding WidthColumnContractCustomer, Mode=TwoWay}"/>
<GridViewColumn DisplayMemberBinding="{Binding Source}" Header="{x:Static p:Resources.Source}" Width="{Binding WidthColumnContractSource, Mode=TwoWay}"/>
</GridView>
</ListView.View>
</ListView>
uj5u.com熱心網友回復：
您可以修改您的行為以處理擴展MultiSelector（如DataGrid）和ListBox單獨的控制元件。ListBox（因此ListView也是）不是但在將屬性設定為不同于（這是默認值）MultiSelector時支持多選。
對于每個其他簡單的選擇器，您都必須手動跟蹤所選專案。您還必須攔截事件以防止選擇器在多選模式下取消選擇所選專案 -僅支持單個專案選擇。ListBox.SelectionModeSelectionMode.SingleSelector.UnselectedSelector
Selector以下示例顯示了在附件不是 aListBox或 a的情況下如何跟蹤所選專案MultiSelector。出于這個原因，該行為公開了一個公共的只讀SelectedItems依賴屬性。
該示例還顯示了如何觀察按下的鍵盤鍵以過濾多選用戶操作。此示例將 Shift或Ctrl鍵過濾為觸發多選行為的手勢：按下CTRL時隨機多選和按下Shift鍵時進行范圍選擇。否則，Selector它將像往常一樣運行（釋放滑鼠左鍵時單選）。
選擇器服務.cs
public class SelectorService : DependencyObject
{
#region IsSelectItemOnMouseUpEnabled attached property
public static readonly DependencyProperty IsSelectItemOnMouseUpEnabledProperty = DependencyProperty.RegisterAttached(
"IsSelectItemOnMouseUpEnabled",
typeof(bool),
typeof(SelectorService),
new PropertyMetadata(default(bool), OnIsSelectItemOnMouseUpEnabledChanged));
public static void SetIsSelectItemOnMouseUpEnabled(DependencyObject attachedElement, bool value) => attachedElement.SetValue(IsSelectItemOnMouseUpEnabledProperty, value);
public static bool GetIsSelectItemOnMouseUpEnabled(DependencyObject attachedElement) => (bool)attachedElement.GetValue(IsSelectItemOnMouseUpEnabledProperty);
#endregion IsSelectItemOnMouseUpEnabled attached property
#region SelectedItems attached property
public static IList GetSelectedItems(DependencyObject attachedElement) => (IList)attachedElement.GetValue(SelectedItemsProperty);
public static void SetSelectedItems(DependencyObject attachedElement, IList value) => attachedElement.SetValue(SelectedItemsPropertyKey, value);
private static readonly DependencyPropertyKey SelectedItemsPropertyKey = DependencyProperty.RegisterAttachedReadOnly(
"SelectedItems",
typeof(IList),
typeof(SelectorService),
new PropertyMetadata(default));
public static readonly DependencyProperty SelectedItemsProperty = SelectedItemsPropertyKey.DependencyProperty;
#endregion SelectedItems attached property
#region SelectionMode attached property (private)
private static SelectionMode GetOriginalSelectionModeBackup(DependencyObject attachedElement) => (SelectionMode)attachedElement.GetValue(OriginalSelectionModeBackupProperty);
private static void SetOriginalSelectionModeBackup(DependencyObject attachedElement, SelectionMode value) => attachedElement.SetValue(OriginalSelectionModeBackupProperty, value);
private static readonly DependencyProperty OriginalSelectionModeBackupProperty = DependencyProperty.RegisterAttached(
"OriginalSelectionModeBackup",
typeof(SelectionMode),
typeof(SelectorService),
new PropertyMetadata(default));
#endregion SelectionMode attached property
private static bool IsRandomMultiSelectEngaged
=> Keyboard.Modifiers is ModifierKeys.Control;
private static bool IsRangeMultiSelectEngaged
=> Keyboard.Modifiers is ModifierKeys.Shift;
private static Dictionary<Selector, bool> IsMultiSelectAppliedMap { get; } = new Dictionary<Selector, bool>();
private static int SelectedRangeStartIndex { get; set; } = -1;
private static int SelectedRangeEndIndex { get; set; } = -1;
private static void OnIsSelectItemOnMouseUpEnabledChanged(DependencyObject attachedElement, DependencyPropertyChangedEventArgs e)
{
if (attachedElement is not Selector selector)
{
return;
}
if ((bool)e.NewValue)
{
WeakEventManager<FrameworkElement, MouseButtonEventArgs>.AddHandler(selector, nameof(selector.PreviewMouseLeftButtonDown), OnPreviewLeftMouseButtonDown);
WeakEventManager<FrameworkElement, MouseButtonEventArgs>.AddHandler(selector, nameof(selector.PreviewMouseLeftButtonUp), OnPreviewLeftMouseButtonUp);
if (selector.IsLoaded)
{
InitializeAttachedElement(selector);
}
else
{
selector.Loaded = OnSelectorLoaded;
}
}
else
{
WeakEventManager<FrameworkElement, MouseButtonEventArgs>.RemoveHandler(selector, nameof(selector.PreviewMouseLeftButtonDown), OnPreviewLeftMouseButtonDown);
WeakEventManager<FrameworkElement, MouseButtonEventArgs>.RemoveHandler(selector, nameof(selector.PreviewMouseLeftButtonUp), OnPreviewLeftMouseButtonUp);
SetSelectedItems(selector, null);
IsMultiSelectAppliedMap.Remove(selector);
selector.Loaded -= OnSelectorLoaded;
if (selector is ListBox listBox)
{
listBox.SelectionMode = GetOriginalSelectionModeBackup(listBox);
}
}
}
private static void OnSelectorLoaded(object sender, RoutedEventArgs e)
{
var selector = sender as Selector;
selector.Loaded -= OnSelectorLoaded;
InitializeAttachedElement(selector);
}
private static void InitializeAttachedElement(Selector selector)
{
IList selectedItems = new List<object>();
if (selector is ListBox listBox)
{
ValidateListBoxSelectionMode(listBox);
selectedItems = listBox.SelectedItems;
}
else if (selector is MultiSelector multiSelector)
{
selectedItems = multiSelector.SelectedItems;
}
else if (selector.SelectedItem is not null)
{
selectedItems.Add(selector.SelectedItem);
}
SetSelectedItems(selector, selectedItems);
IsMultiSelectAppliedMap.Add(selector, false);
}
private static void OnUnselected(object? sender, RoutedEventArgs e)
{
var itemContainer = sender as DependencyObject;
Selector.SetIsSelected(itemContainer, true);
Selector.RemoveUnselectedHandler(itemContainer, OnUnselected);
}
private static void OnPreviewLeftMouseButtonUp(object sender, MouseButtonEventArgs e)
{
var selector = sender as Selector;
DependencyObject itemContainerToSelect = ItemsControl.ContainerFromElement(selector, e.OriginalSource as DependencyObject);
DependencyObject currentSelectedItemContainer = selector.ItemContainerGenerator.ContainerFromItem(selector.SelectedItem);
if (itemContainerToSelect is null)
{
return;
}
if (IsRandomMultiSelectEngaged)
{
MultiSelectItems(selector, itemContainerToSelect, currentSelectedItemContainer);
}
else if (IsRangeMultiSelectEngaged)
{
MultiSelectRangeOfItems(selector, itemContainerToSelect, currentSelectedItemContainer);
}
else
{
SingleSelectItem(selector, itemContainerToSelect, currentSelectedItemContainer);
}
IsMultiSelectAppliedMap[selector] = IsRandomMultiSelectEngaged || IsRangeMultiSelectEngaged;
}
private static void MultiSelectRangeOfItems(Selector selector, DependencyObject itemContainerToSelect, DependencyObject currentSelectedItemContainer)
{
int clickedContainerIndex = selector.ItemContainerGenerator.IndexFromContainer(itemContainerToSelect);
// In case there is not any preselected item. Otherwis SingleSlectItem() has already set the SelectedRangeStartIndex property.
if (SelectedRangeStartIndex == -1)
{
SelectedRangeStartIndex = clickedContainerIndex;
DependencyObject itemContainer = selector.ItemContainerGenerator.ContainerFromIndex(SelectedRangeStartIndex);
MultiSelectItems(selector, itemContainer, currentSelectedItemContainer);
return;
}
// Complete the range selection
else if (SelectedRangeEndIndex == -1)
{
bool isSelectionRangeFromTopToBotton = clickedContainerIndex > SelectedRangeStartIndex;
if (isSelectionRangeFromTopToBotton)
{
SelectedRangeEndIndex = clickedContainerIndex;
}
else
{
// Selection is from bottom to top, so we need to swap start and end index
// as they are used to initialize the for-loop.
SelectedRangeEndIndex = SelectedRangeStartIndex;
SelectedRangeStartIndex = clickedContainerIndex;
}
for (int itemIndex = SelectedRangeStartIndex; itemIndex <= SelectedRangeEndIndex; itemIndex )
{
DependencyObject itemContainer = selector.ItemContainerGenerator.ContainerFromIndex(itemIndex);
bool isContainerUnselected = !Selector.GetIsSelected(itemContainer);
if (isContainerUnselected)
{
MultiSelectItems(selector, itemContainer, currentSelectedItemContainer);
}
}
// Only remember start index to append sequential ranges (more clicks while Shift key is pressed)
// and invalidate the end index.
SelectedRangeEndIndex = -1;
}
}
private static void MultiSelectItems(Selector? selector, DependencyObject itemContainerToSelect, DependencyObject currentSelectedItemContainer)
{
bool oldIsSelectedValue = Selector.GetIsSelected(itemContainerToSelect);
// Toggle the current state
bool newIsSelectedValue = oldIsSelectedValue ^= true;
if (selector is ListBox listBox)
{
// In case the mode was overriden externally, force it back
// but store the changed value to allow roll back when the behavior gets disabled.
ValidateListBoxSelectionMode(listBox);
}
// If the current Selector instance does not support native multi select
// we need to prevent the Selector from unselecting previous selected items.
// By setting unselected items back to selected we can enforce a visual multi select feedback.
if (selector is not MultiSelector and not ListBox)
{
if (newIsSelectedValue && currentSelectedItemContainer is not null)
{
Selector.AddUnselectedHandler(currentSelectedItemContainer, OnUnselected);
}
}
Selector.SetIsSelected(itemContainerToSelect, newIsSelectedValue);
(itemContainerToSelect as UIElement)?.Focus();
if (selector is not MultiSelector and not ListBox)
{
object item = selector.ItemContainerGenerator.ItemFromContainer(itemContainerToSelect);
IList selectedItems = GetSelectedItems(selector);
if (newIsSelectedValue)
{
selectedItems.Add(item);
}
else
{
selectedItems.Remove(item);
}
}
}
private static void SingleSelectItem(Selector? selector, DependencyObject itemContainerToSelect, DependencyObject currentSelectedItemContainer)
{
bool isPreviousSelectMultiSelect = IsMultiSelectAppliedMap[selector];
if (!isPreviousSelectMultiSelect)
{
// Unselect the currently selected
if (currentSelectedItemContainer is not null)
{
Selector.SetIsSelected(currentSelectedItemContainer, false);
}
}
// If the Selector has multiple selected items and an item was clicked without the modifier key pressed,
// then we need to switch back to single selection mode and only select the currently clicked item.
else
{
// Invalidate tracked multi select range
SelectedRangeStartIndex = -1;
SelectedRangeEndIndex = -1;
if (selector is ListBox listBox)
{
ValidateListBoxSelectionMode(listBox);
listBox.UnselectAll();
}
else if (selector is MultiSelector multiSelector)
{
multiSelector.UnselectAll();
}
else
{
IList selectedItems = GetSelectedItems(selector);
foreach (object item in selectedItems)
{
DependencyObject itemContainer = selector.ItemContainerGenerator.ContainerFromItem(item);
Selector.SetIsSelected(itemContainer, false);
}
selectedItems.Clear();
}
}
// Execute single selection
Selector.SetIsSelected(itemContainerToSelect, true);
(itemContainerToSelect as UIElement)?.Focus();
if (selector is not MultiSelector and not ListBox)
{
IList selectedItems = GetSelectedItems(selector);
selectedItems.Clear();
selectedItems.Add(selector.SelectedItem);
}
// Track index in case the next click enabled select range (press Shift while click)
int clickedContainerIndex = selector.ItemContainerGenerator.IndexFromContainer(itemContainerToSelect);
SelectedRangeStartIndex = clickedContainerIndex;
return;
}
private static void ValidateListBoxSelectionMode(ListBox listBox)
{
if (listBox.SelectionMode is not SelectionMode.Extended)
{
// In case the mode was overriden externally, force it back
// but store the changed value to allow roll back when the behavior gets disabled.
SetOriginalSelectionModeBackup(listBox, listBox.SelectionMode);
listBox.SelectionMode = SelectionMode.Extended;
}
}
private static void OnPreviewLeftMouseButtonDown(object sender, MouseButtonEventArgs e)
=> e.Handled = true;
}
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