c# - 如何创建三态 CheckBox 来汇总 ListView 中所有 CheckBox 的状态？

Question

我有一个 WPF ListView，其中包含 CheckBox 列和自定义对象的其他列。我想在这个 ListView 上放置另一个 CheckBox——三态 CheckBox——所以它的状态将绑定(bind)到选中的复选框。如果每个人都被选中，则上部复选框的状态将被选中。如果只有其中一些，状态将是不确定的。否则它的状态将被取消检查。 (就像在 Gmail 中一样)

Answer 1

我找到了一些解决方案

<StackPanel>
  <CheckBox Name="chbxAll" Checked="chbxAll_Checked" Unchecked="chbxAll_Unchecked" Indeterminate="chbxAll_Indeterminate" IsThreeState="True" >Select All</CheckBox>
     <ListView Name="lstFoundedFiles" SelectionChanged="lstFoundedFiles_SelectionChanged" SelectionMode="Multiple" ItemsSource="{Binding Files}">
       <ListView.Resources>
         <Style TargetType="ListViewItem">
           <Style.Triggers>
             <Trigger Property="IsSelected" Value="True">
               <Setter Property="Background" Value="Aquamarine"></Setter>
             </Trigger>
           </Style.Triggers>
         </Style>
       </ListView.Resources>
       <ListView.View>
         <GridView>
           <GridViewColumn Width="50" Header="Check">
             <GridViewColumn.CellTemplate>
               <DataTemplate>
                 <CheckBox x:Name="chbxItem" IsChecked="{Binding Path=IsSelected, 
                                                    RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListViewItem}}}"/>
               </DataTemplate>
             </GridViewColumn.CellTemplate>
           </GridViewColumn>
          <GridViewColumn Header="File">
            <GridViewColumn.CellTemplate>
              <DataTemplate>
                <TextBlock Text="{Binding Name}" ></TextBlock>
              </DataTemplate>
            </GridViewColumn.CellTemplate>
         </GridViewColumn>
         <GridViewColumn Header="Location">
           <GridViewColumn.CellTemplate>
             <DataTemplate>
              <TextBlock Text="{Binding Path}"></TextBlock>
             </DataTemplate>
          </GridViewColumn.CellTemplate>
       </GridViewColumn>
     </GridView>
   </ListView.View>
 </ListView>
</StackPanel>

============================================= ===========================

代码隐藏:

// True if we should ignore check change events.
private bool IgnoreCheckChangeEvents = false;

private void lstFoundedFiles_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
  if (IgnoreCheckChangeEvents) return;

  int temp = lstFoundedFiles.SelectedItems.Count;
  IgnoreCheckChangeEvents = true;
  if (temp == lstFoundedFiles.Items.Count)
  {
    chbxAll.IsChecked = true;
  }
  else if (temp == 0)
  {
    chbxAll.IsChecked = false;
  }
  else
  {
    chbxAll.IsChecked = null;
  }

  IgnoreCheckChangeEvents = false;
}

private void chbxAll_Checked(object sender, RoutedEventArgs e)
{
  if (IgnoreCheckChangeEvents) return;

  IgnoreCheckChangeEvents = true;

  lstFoundedFiles.SelectAll();

  IgnoreCheckChangeEvents = false;
}

private void chbxAll_Unchecked(object sender, RoutedEventArgs e)
{
  if (IgnoreCheckChangeEvents) return;

  IgnoreCheckChangeEvents = true;

  lstFoundedFiles.UnselectAll();

  IgnoreCheckChangeEvents = false;
}

private void chbxAll_Indeterminate(object sender, RoutedEventArgs e)
{
  if (IgnoreCheckChangeEvents) return;

  chbxAll.IsChecked = false;

  IgnoreCheckChangeEvents = true;

  lstFoundedFiles.UnselectAll();

  IgnoreCheckChangeEvents = false;
}