将命令参数传递给 WPF 中 ViewModel 中的方法? [英] Pass command parameter to method in ViewModel in WPF?

问题描述

我正在尝试将 CommandParameter 传递给我的 ViewModel 中的方法.如何做到这一点?

I am trying to pass CommandParameter to the method in my ViewModel. How to do this?

private void Open(object sender)
{
    if (sender==this.objMainWindow.btnHistory)
    {
        objMainWindow.Container.Child = objHistory;
    }

    if (sender == this.objMainWindow.btnNew_Item)
    {
        objMainWindow.Container.Child = objNewItem;
    }

    if (sender == this.objMainWindow.btnSide_Effects)
    {
        objMainWindow.Container.Child = objSideEffect;
    }
}

这是我在 ViewModel 中的方法，我想传递 CommandParameter.我使用 CommandParameter 作为按钮.

This is my meyhod in ViewModel that I want to pass CommandParameter. I use CommandParameter for button.

推荐答案

ViewModel"暗示 MVVM.如果您正在使用 MVVM，您不应该将视图传递到您的视图模型中.通常，您会在 XAML 中执行以下操作:

"ViewModel" implies MVVM. If you're doing MVVM you shouldn't be passing views into your view models. Typically you do something like this in your XAML:

<Button Content="Edit" 
        Command="{Binding EditCommand}"
        CommandParameter="{Binding ViewModelItem}" >

然后在你的视图模型中:

And then this in your view model:

private ViewModelItemType _ViewModelItem;
public ViewModelItemType ViewModelItem
{
    get
    {
        return this._ViewModelItem;
    }
    set
    {
        this._ViewModelItem = value;
        RaisePropertyChanged(() => this.ViewModelItem);
    }
}

public ICommand EditCommand { get { return new RelayCommand<ViewModelItemType>(OnEdit); } }
private void OnEdit(ViewModelItemType itemToEdit)
{
    ... do something here...
}

显然这只是为了说明这一点，如果您只有一个名为 ViewModelItem 的属性需要编辑，那么您就不需要将其作为命令参数传入.

Obviously this is just to illustrate the point, if you only had one property to edit called ViewModelItem then you wouldn't need to pass it in as a command parameter.

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