Question

我正在使用Mahapp而我正在尝试等待对话框的结果，但是编译器强调了ShowMessageAsync并显示了我：

ShowMessageAsync在当前上下文中不存在

这是代码：

private async void ShowMessageBox(object sender, RoutedEventArgs e)
{
    var result = await ShowMessageAsync("Hello!", "Welcome to the world of metro!", 
        MahApps.Metro.Controls.MessageDialogStyle.AffirmativeAndNegative);
    if (result == MessageDialogResult.Affirmative)
    {
        this.ShowMessageAsync("Result", "You said: OK");
    }
    else
    {
        this.ShowMessageAsync("Result", "You said: CANCEL");
    }
}

Answer 1

mahapps异步消息框的扩展方法。

using System.Windows;
using MahApps.Metro.Controls;
using MahApps.Metro.Controls.Dialogs;
using System.Threading.Tasks;
public static class InfoBox
{
    public async static Task<MessageDialogResult> ShowMessageAsync(string title, string Message, MessageDialogStyle style = MessageDialogStyle.Affirmative, MetroDialogSettings settings = null)
    {
         return await ((MetroWindow)(Application.Current.MainWindow)).ShowMessageAsync(title, Message, style, settings);
    }
}

用法

var res = await InfoBox.ShowMessageAsync(...); 
if (res == MessageDialogResult.Affirmative) 
{ 
     /* Do something*/ 
}

Answer 2

您必须添加this关键字，因为ShowMessageAsync是一种扩展方法，而不是MetroWindow类的成员。

var result = await this.ShowMessageAsync("Hello!", ...);
                 //^^^^^ here

您还有其他错误。而不是：

 MahApps.Metro.Controls.MessageDialogStyle.AffirmativeAndNegative

使用：

MahApps.Metro.Controls.Dialogs.MessageDialogStyle.AffirmativeAndNegative

你必须在这些行之前添加等待：

if (result == MessageDialogResult.Affirmative)
{
    await this.ShowMessageAsync("Result", "You said: OK");
   //^^^^ here
}
else
{
    await this.ShowMessageAsync("Result", "You said: CANCEL");
   //^^^^ here
}

无法在ShowMessageAsync上使用await

2 个答案: