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我想用setter設置WPF數據網格中按鈕的命令。但似乎在我返回 CreateInstanceCore()
中的一個副本後,DP屬性CommandProperty
獲得了其默認值null
的過度寫入,因此原始命令會丟失。DataGrid CellStyle Setter with Freezable StaticRecource
如果我直接綁定StaticResource
它沒有問題。 有沒有辦法阻止該行爲或其他解決方案?
public class ResourceCommand : Freezable, ICommand {
public ICommand Command {
get { return (ICommand)GetValue(CommandProperty); }
set { SetValue(CommandProperty, value); }
}
// Using a DependencyProperty as the backing store for Command. This enables animation, styling, binding, etc...
public static readonly DependencyProperty CommandProperty =
DependencyProperty.Register("Command", typeof(ICommand), typeof(ResourceCommand), new UIPropertyMetadata(null, CommandPropertyChangedCallback));
static void CommandPropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) {
ResourceCommand resourceCommand = (ResourceCommand)d;
int h = resourceCommand.GetHashCode();
if (e.OldValue != null)
((ICommand)e.OldValue).CanExecuteChanged -= resourceCommand.OnCanExecuteChanged;
if (e.NewValue != null)
((ICommand)e.NewValue).CanExecuteChanged += resourceCommand.OnCanExecuteChanged;
}
#region ICommand Member
public bool CanExecute(object parameter) {
if (Command == null)
return false;
return Command.CanExecute(parameter);
}
public event EventHandler CanExecuteChanged;
void OnCanExecuteChanged(object sender, EventArgs e) {
if (CanExecuteChanged != null)
CanExecuteChanged(sender, e);
}
public void Execute(object parameter) {
Command.Execute(parameter);
}
#endregion
protected override Freezable CreateInstanceCore() {
ResourceCommand ResourceCommand = new ResourceCommand();
ResourceCommand.Command = Command;
return ResourceCommand;
}
}
XAML:
<Window.Resources>
<local:ResourceCommand x:Key="FirstCommand" Command="{Binding FirstCommand}" />
<local:ResourceCommand x:Key="SecondCommand" Command="{Binding SecondCommand}" />
</Window.Resources>
<Grid>
<DataGrid ItemsSource="{Binding Collection}">
<DataGrid.Columns>
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Content="Click me">
<Button.Style>
<Style TargetType="Button">
<Setter Property="Command" Value="{StaticResource FirstCommand}" />
</Style>
</Button.Style></Button>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
</Grid>
1.在DataGrid和Command之外的按鈕綁定爲無樣式: Works。但之前也工作過。 2.使用樣式設置器的DataGrid和命令設置之外的按鈕: 不起作用。調用CreateInstanceCore()。 2. DataGrid和Command中的按鈕綁定時沒有樣式或設置Command over style: 不起作用。調用CreateInstanceCore()。 – 2011-01-27 07:46:22