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如何在 wpf 中加载窗口时触发命令

发布于 2024-09-13 01:48:50 字数 82 浏览 4 评论 0原文

是否可以触发命令来通知窗口已加载。另外，我没有使用任何 MVVM 框架（某种意义上的框架，Caliburn、Onxy、MVVM Toolkit 等）

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提赋 2024-09-20 01:48:50

为了避免视图上的代码隐藏，请使用交互库（System.Windows.Interactivity dll，您可以从 Microsoft 免费下载 - 也随 Expression Blend 一起提供）。

然后您可以创建一个执行命令的行为。这样，触发器调用行为，行为又调用命令。

<ia:Interaction.Triggers>
    <ia:EventTrigger EventName="Loaded">
        <custombehaviors:CommandAction Command="{Binding ShowMessage}" Parameter="I am loaded"/>
    </ia:EventTrigger>
</ia:Interaction.Triggers>

CommandAction（也使用 System.Windows.Interactivity）可以如下所示：

public class CommandAction : TriggerAction<UIElement>
{
    public static DependencyProperty CommandProperty = DependencyProperty.Register("Command", typeof(ICommand), typeof(CommandAction), null);
    public ICommand Command
    {
        get
        {
            return (ICommand)GetValue(CommandProperty);
        }
        set
        {
            SetValue(CommandProperty, value);
        }
    }


    public static DependencyProperty ParameterProperty = DependencyProperty.Register("Parameter", typeof(object), typeof(CommandAction), null);
    public object Parameter
    {
        get
        {
            return GetValue(ParameterProperty);
        }
        set
        {
            SetValue(ParameterProperty, value);

        }
    }

    protected override void Invoke(object parameter)
    {
        Command.Execute(Parameter);            
    }
}

To avoid code behind on your View, use the Interactivity library (System.Windows.Interactivity dll which you can download for free from Microsoft - also comes with Expression Blend).

Then you can create a behavior that executes a command. This way the Trigger calls the Behavior which calls the Command.

<ia:Interaction.Triggers>
    <ia:EventTrigger EventName="Loaded">
        <custombehaviors:CommandAction Command="{Binding ShowMessage}" Parameter="I am loaded"/>
    </ia:EventTrigger>
</ia:Interaction.Triggers>

CommandAction (also uses System.Windows.Interactivity) can look like:

public class CommandAction : TriggerAction<UIElement>
{
    public static DependencyProperty CommandProperty = DependencyProperty.Register("Command", typeof(ICommand), typeof(CommandAction), null);
    public ICommand Command
    {
        get
        {
            return (ICommand)GetValue(CommandProperty);
        }
        set
        {
            SetValue(CommandProperty, value);
        }
    }


    public static DependencyProperty ParameterProperty = DependencyProperty.Register("Parameter", typeof(object), typeof(CommandAction), null);
    public object Parameter
    {
        get
        {
            return GetValue(ParameterProperty);
        }
        set
        {
            SetValue(ParameterProperty, value);

        }
    }

    protected override void Invoke(object parameter)
    {
        Command.Execute(Parameter);            
    }
}

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往日情怀 2024-09-20 01:48:50

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
       ApplicationCommands.New.Execute(null, targetElement); 
       // or this.CommandBindings[0].Command.Execute(null); 
    }

和 xaml

    Loaded="Window_Loaded"

    private void Window_Loaded(object sender, RoutedEventArgs e)
    {
       ApplicationCommands.New.Execute(null, targetElement); 
       // or this.CommandBindings[0].Command.Execute(null); 
    }

and xaml

    Loaded="Window_Loaded"

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萌辣 2024-09-20 01:48:50

AttachedCommandBehavior V2 aka ACB<提出了一种更通用的使用行为的方法< /a> 它甚至支持多个事件到命令的绑定，

这是一个非常基本的使用示例：

<Window x:Class="Example.YourWindow"
        xmlns:local="clr-namespace:AttachedCommandBehavior;assembly=AttachedCommandBehavior"
        local:CommandBehavior.Event="Loaded"
        local:CommandBehavior.Command="{Binding DoSomethingWhenWindowIsLoaded}"
        local:CommandBehavior.CommandParameter="Some information"
/>

A more generic way using behaviors is proposed at AttachedCommandBehavior V2 aka ACB and it even supports multiple event-to-command bindings,

Here is a very basic example of use:

<Window x:Class="Example.YourWindow"
        xmlns:local="clr-namespace:AttachedCommandBehavior;assembly=AttachedCommandBehavior"
        local:CommandBehavior.Event="Loaded"
        local:CommandBehavior.Command="{Binding DoSomethingWhenWindowIsLoaded}"
        local:CommandBehavior.CommandParameter="Some information"
/>

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桃扇骨 2024-09-20 01:48:50

现在这更容易做到。只需包含以下命名空间：

xmlns:i="http://schemas.microsoft.com/xaml/behaviors"

并像这样利用它：

<i:Interaction.Triggers>
    <i:EventTrigger EventName="Loaded">
        <i:InvokeCommandAction Command="{Binding CommandInViewModel}"/>
    </i:EventTrigger>
</i:Interaction.Triggers>

This is much easier to do now. Simply include the following namespace:

xmlns:i="http://schemas.microsoft.com/xaml/behaviors"

And leverage it like this:

<i:Interaction.Triggers>
    <i:EventTrigger EventName="Loaded">
        <i:InvokeCommandAction Command="{Binding CommandInViewModel}"/>
    </i:EventTrigger>
</i:Interaction.Triggers>

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~没有更多了~