我有一些XAML如下:
<UserControl x:Class="Foo">
<UserControl.Resources>
<ContextMenu x:Key="ContextMenu1">
<MenuItem Header="Command 1a"/>
<MenuItem Header="Command 1b"/>
</ContextMenu>
<ContextMenu x:Key="ContextMenu2">
<MenuItem Header="Command 2a"/>
<MenuItem Header="Command 2b"/>
</ContextMenu>
</UserControl.Resources>
<DockPanel>
<TreeView>
<TreeView.Resources>
<DataTemplate DataType="{x:Type Type1}">
<StackPanel ContextMenu="{StaticResource ContextMenu1"}/>
</DataTemplate>
<DataTemplate DataType="{x:Type Type2}">
<StackPanel ContextMenu="{StaticResource ContextMenu2"}/>
</DataTemplate>
</TreeView.Resources>
</TreeView>
</DockPanel>
</UserControl>
和类似于以下内容的代码:
public class Type1 {
public void OnCommand1a() {}
public void OnCommand1b() {}
}
public class Type2 {
public void OnCommand2a() {}
public void OnCommand2b() {}
}
单击菜单上的相应项目,我需要做什么才能调用相应的功能?
如果我添加:
Command="{Binding Path=OnCommand1a}" CommandTarget="{Binding Path=PlacementTarget}"
等然后在运行时我得到有关OnCommand1a不是属性的错误。一些搜索表明这与RoutedUIEvent有关,但我真的不明白那是什么。
如果我使用
Click="OnCommand1a"
然后它在UserControl上查找OnCommand1a()而不是绑定到DataTemplate的类型。
处理此问题的标准方法是什么?
答案 0 :(得分:2)
首先,您需要一个扩展ICommand的类。 你可以用这个:
public class DelegateCommand : ICommand
{
private readonly Action<object> executeMethod = null;
private readonly Func<object, bool> canExecuteMethod = null;
public event EventHandler CanExecuteChanged
{
add { return; }
remove { return; }
}
public DelegateCommand(Action<object> executeMethod, Func<object, bool> canExecuteMethod)
{
this.executeMethod = executeMethod;
this.canExecuteMethod = canExecuteMethod;
}
public bool CanExecute(object parameter)
{
if (canExecuteMethod == null) return true;
return this.canExecuteMethod(parameter);
}
public void Execute(object parameter)
{
if (executeMethod == null) return;
this.executeMethod(parameter);
}
}
然后,在您的类Type1中,您必须声明:
public DelegateCommand OnCommand1a {get; private set;}
并以这种方式在Type1构造函数中设置它:
OnCommand1a = new DelegateCommand(c => Cmd1a(), null);
其中Cmd1a是:
private void Cmd1a()
{
//your code here
}
最后,在你的xaml中:
Command="{Binding Path=OnCommand1a}"