带有 MVVM 模式的 WPF MessageBox? [英] WPF MessageBox with MVVM pattern?

问题描述

假设我想向用户显示一些验证错误.在 MVVM 模式中，我可以有一个绑定到我的视图模型上的某些属性的标签.但是如果我想在严格遵守 MVVM 模式的同时显示一个消息框呢?我的视图模型将绑定到什么，它将如何触发要创建/显示的消息框?

Say I want to display some validation error to the user. In the MVVM pattern, I could have a label that is bound to some property on my viewmodel. But what if I wanted to show a message box while strictly adhering to the MVVM pattern. What would my viewmodel bind to, and how would it trigger a message box to be created/displayed?

推荐答案

有一个接口 IMessageBoxService as:

interface IMessageBoxService
{
    bool ShowMessage(string text, string caption, MessageType messageType);
}

创建一个WPFMessageBoxService类:

using System.Windows;

class WPFMessageBoxService : IMessageBoxService
{
    bool ShowMessage(string text, string caption, MessageType messageType)
    {
        // TODO: Choose MessageBoxButton and MessageBoxImage based on MessageType received
        MessageBox.Show(text, caption, MessageBoxButton.OK, MessageBoxImage.Information);
    }
}

在您的 ViewModel 中接受 IMessageBoxService 作为构造函数参数并使用 DI/IoC 注入 WPFMessageBoxService.

In your ViewModel accept IMessageBoxService as a constructor parameter and inject WPFMessageBoxService using DI/IoC.

在 ViewModel 中，使用 IMessageBoxService.ShowMessage 来显示 MessageBox.

In the ViewModel, use IMessageBoxService.ShowMessage to show the MessageBox.

ShowMessageCommand = new DelegateCommand (
    () => messageBoxService.ShowMessage(message, header, MessageType.Information)
);

根据您的需要自定义 IMessageBoxService 接口，并取一个更好的名称.

Customize IMessageBoxService interface to your needs, and pick up a better name.

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