[英]WPF event binding from View to ViewModel?
What is the best way to bind a WPF event in the View to the ViewModel?将 View 中的 WPF 事件绑定到 ViewModel 的最佳方法是什么?
I have a drop event in my View but I want to replace it to the ViewModel due binding.我的视图中有一个放置事件,但我想将其替换为 ViewModel 到期绑定。
Found several solutions but none of them did what I expected.找到了几个解决方案,但没有一个达到我的预期。
View code:查看代码:
<TextBox
AllowDrop="True"
PreviewDrop="email_Drop" />
One way to handle events in MVVM and XAML is to use the Blend Interactivity features.在 MVVM 和 XAML 中处理事件的一种方法是使用混合交互功能。 This namespace contains the InvokeCommandAction and the CallMethodAction classes.
此命名空间包含 InvokeCommandAction 和 CallMethodAction 类。
InvokeCommandAction lets you bind any event to a view-model command while CallMethodAction lets you bind any event to a view-model method. InvokeCommandAction 允许您将任何事件绑定到视图模型命令,而 CallMethodAction 允许您将任何事件绑定到视图模型方法。
For example if you want to bind the DoubleClick event of a Button to a view-model command you would do like this:例如,如果您想将 Button 的 DoubleClick 事件绑定到视图模型命令,您可以这样做:
<Button>
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDoubleClick">
<i:InvokeCommandAction Command="{Binding Path=DoSomethingCommand}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
And declaring this namespace:并声明这个命名空间:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
All you need to reference it in your projects is to install Expression Blend or the Expression Blend SDK.您需要在项目中引用它,只需安装 Expression Blend 或 Expression Blend SDK。
Well one way to do is to convert that event into a command and then bind it to presenter command, ie by defining event behaviour.一种方法是将该事件转换为命令,然后将其绑定到演示者命令,即通过定义事件行为。
See this, WPF Event Binding to ViewModel (for non-Command classes)看到这个, WPF Event Binding to ViewModel(对于非Command类)
<Button MouseDoubleClick="{eb:EventBinding Command=DoSomethingCommand}">
</Button>
Command命令
{eb:EventBinding} (Simple naming pattern to find Command) {eb:EventBinding}(查找命令的简单命名模式)
{eb:EventBinding Command=CommandName} {eb:EventBinding 命令=命令名称}
CommandParameter命令参数
$e (EventAgrs) $e (EventAgrs)
$this or $this.Property $this 或 $this.Property
string细绳
https://github.com/JonghoL/EventBindingMarkup https://github.com/JonghoL/EventBindingMarkup
I get the viewmodel from the bindingcontext and activate my viewmodel method from there我从 bindingcontext 获取 viewmodel 并从那里激活我的 viewmodel 方法
public partial class ParentView : ContentPage
{
public ParentView()
{
InitializeComponent();
}
private void LanguagePicker_SelectedIndexChanged(object sender, System.EventArgs e)
{
var parentViewModel = (ParentViewModel)this.BindingContext;
parentViewModel.SelectedLanguageChanged(sender,e);
}
}
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