将命令目标设置为模板部分 [英] Set command target to template part

问题描述

1)具有CommandBindings的自定义DataGrid.

1) Custom DataGrid with CommandBindings.

2)一个RoutedCommand定义.

2) A RoutedCommand Definition.

3)命令目标定义. (XAML)

3) A Command Target Definition. (XAML)

CS:

    //(1)
    public class CustomDataGrid : DataGrid
    {
         this.CommandBindings.Add(new CommandBinding(Commands.ClearInputCommand, 
                     ClearFilter, ClearFilterCanExecute));                      
    }

    //(2)
    public static class Commands
    {
        public static RoutedCommand ClearInputCommand = new RoutedCommand("ClearInputCommand", typeof(Commands));   
    }  

XAML:

    <!-- (3) -->
    <local:CustomDataGrid x:Name="grid" />                                                                                  
    <Button Command="{x:Static p:Commands.ClearInputCommand}" 
            CommandTarget="{Binding ElementName=grid}"/> 

我想将CommandBindings转移到CustomDataGrid的子级(它是Template中的一个元素)，从而解决了对此"Custom" DataGrid的需求，而只需要更改常规DataGrid的模板.

I would like to transfer the CommandBindings to a child of my CustomDataGrid (an Element in it's Template) , thus dissolving the need for a this "Custom" DataGrid and only a change in a template of a regular DataGrid.

XAML:CustomDataGridTemplate.

XAML : CustomDataGridTemplate.

       <Template TargetType="{x:Type p:CustomDataGrid}" >
            ......
            <p:SomeCustomElement x:Name="I WANT TO BE THE COMMAND TARGET !" />
            ......
       </Template>

我怎样才能做到这一点?是否有向该命令注册SomeCustomElement的过程?

how can i achieve this ? is there a was of registering SomeCustomElement to that command ?

推荐答案

好，所以在所有类型的RoutedCommand旁边，我放置了一些扩展方法来注册其自身类型的路由命令，

Ok , so along side all the type of RoutedCommands i placed a few extension methods to register the routed command with the type it self ,

public static class Commands
{
    public static RoutedCommand ClearInputCommand = new RoutedCommand("ClearInputCommand", typeof(Commands));

    public static void RegisterCommand(this UIElement uiElement, RoutedCommand command, ExecutedRoutedEventHandler execute, CanExecuteRoutedEventHandler canExecute = null)
    {
        uiElement.RegisterCommand(new CommandBinding(command, execute, canExecute));
    }

    public static void RegisterCommand(this UIElement uiElement, CommandBinding commandBinding)
    {
        CommandManager.RegisterClassCommandBinding(typeof(object), commandBinding);         
    }

    public static void UnRegisterCommand(this UIElement uiElement, RoutedCommand command)
    {
        for (int i = 0; i < uiElement.CommandBindings.Count; i++)
        {
            CommandBinding c = uiElement.CommandBindings[i];
            if (c.Command == command)
            {
                uiElement.CommandBindings.RemoveAt(i);
            }
        }           
    }

    public static void UnRegisterCommand(this UIElement uiElement, CommandBinding commandBinding)
    {
        uiElement.CommandBindings.Remove(commandBinding);                               
    }
} 

然后从该类的构造函数中调用它，我不确定是否需要注销这个棘手的问题，在我看来这可能会导致内存泄漏，因为它包含对Execute和CanExecute委托的引用.

and then just called it from the constructor of that class , i'm not sure if i need to unregister this tough it seems to me that this can cause memory leaks , since it holds a reference to the Execute and CanExecute delegates.

为了注销它们，我将必须跟踪所有已注册的uielements并在应用程序关闭时清除CommandBindings.

in order to Unregister them i would have to keep track of all the registered uielements and clear there CommandBindings on application shut down.

我认为更好的解决方案是使用诸如CompositesCommand之类的棱镜.但这现在就可以了.

i think a better solution would be to use something like prisms CompositeCommand. but this would do for now.

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