MVVM，DialogService和对话框结果 [英] MVVM, DialogService and Dialog Result

问题描述

我目前正在学习WPF/MVVM，并且一直在使用以下问题中的代码来显示使用Dialog Service的对话框(包括Julian Dominguez的布尔值更改):

I'm currently learning WPF/MVVM, and have been using the code in the following question to display dialogs using a Dialog Service (including the boolean change from Julian Dominguez):

在WPF中使用MVVM?

显示对话框效果很好，但是尽管实际上正在显示对话框，但对话框结果始终为假.我的DialogViewModel当前为空，我认为可能需要将DialogViewModel连接到RequestCloseDialog事件.是这样吗?

Displaying a dialog works well, but the dialog result is always false despite the fact that the dialog is actually being shown. My DialogViewModel is currently empty, and I think that maybe I need to "hook up" my DialogViewModel to the RequestCloseDialog event. Is this the case?

推荐答案

您的DialogViewmodel是否实现IDialogResultVMHelper?并且您的View/DataTemplate是否具有到DialogViewmodel的命令绑定，从而引发RequestCloseDialog?

does your DialogViewmodel implement IDialogResultVMHelper? and does your View/DataTemplate has a Command Binding to your DialogViewmodel which raise the RequestCloseDialog?

例如

public class DialogViewmodel : INPCBase, IDialogResultVMHelper
{
    private readonly Lazy<DelegateCommand> _acceptCommand;

    public DialogViewmodel()
    {
        this._acceptCommand = new Lazy<DelegateCommand>(() => new DelegateCommand(() => InvokeRequestCloseDialog(new RequestCloseDialogEventArgs(true)), () => **Your Condition goes here**));
    }

    public event EventHandler<RequestCloseDialogEventArgs> RequestCloseDialog;

    private void InvokeRequestCloseDialog(RequestCloseDialogEventArgs e)
    {
        var handler = RequestCloseDialog;
        if (handler != null) 
            handler(this, e);
    }
}

您的Dialog控件中的任何地方:

anywhere in your Dialog control:

<StackPanel Grid.Row="2" Orientation="Horizontal" HorizontalAlignment="Right" MinHeight="30">
    <Button IsDefault="True" Content="Übernehmen" MinWidth="100" Command="{Binding AcceptCommand}"/>
    <Button IsCancel="True" Content="Abbrechen" MinWidth="100"/>
</StackPanel>

然后您的结果应该在您的视图模型中起作用

and then your result should work in your viewmodel

var dialog = new DialogViewmodel();
var result = _dialogservice.ShowDialog("My Dialog", dialog );

if(result.HasValue && result.Value)
{
    //accept true
}
else
{
    //Cancel or false
}

这篇关于MVVM，DialogService和对话框结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！