如何使用程序创建的按钮在WPF MVVM中创建OnClick命令？ [英] How do you create an OnClick command in WPF MVVM with a programmatically created button?

问题描述

我正在编写一个WPF应用程序，该程序以编程方式创建了一些按钮。如何在ViewModel中为按钮创建OnClick命令？我想添加一条命令，以使用ResetButton清除所有文本框。

I am writing a WPF application that programmatically creates a few buttons. How do you create an OnClick command for a button in the ViewModel? I would like to add a command to clear all TextBoxes with the ResetButton.

new StackPanel
            {
                Orientation = Orientation.Horizontal,
                Children =
                {
                    new Button { Name = "SendButton", Content = "Send", MinWidth = 50, MaxHeight = 30, Margin = new Thickness(5), Background = Brushes.DodgerBlue },
                    new Button { Name = "ResetButton", Content = "Reset", MinWidth = 50, MaxHeight = 30, Margin = new Thickness(5), Background = Brushes.DarkRed}
                }
            });

推荐答案

您是否可以访问视图模型创建堆栈面板？

Do you have access to the view model as you are creating the Stack Panel?

如果是这样，您的视图模型将公开一个命令：

If so, you have your View Model expose a Command:

 var myViewModel = (MyViewModel)this.DataContext;
 Button sendButton = new Button
                     {
                          Name = "SendButton",
                          Command = myViewModel.SendCommand,
                          // etcd
                     }

在您的视图模型中：

class MyViewModel : INotifyPropertyChanged
{ 

     private class SendCommand : ICommand
     {
          private readonly MyViewModel _viewModel;
          public SendCommand(MyViewModel viewModel) 
          {
              this._viewModel = viewModel; 
          }

          void ICommand.Execute(object parameter)
          {
               _viewModel.Send();
          }

          bool ICommand.CanExecute(object p) 
          {
               // Could ask the view nodel if it is able to execute
               // the command at this moment
               return true;
          }
     }

     public ICommand SendCommand
     {
           get
           {
               return new SendCommand(this);
           }
     }

     internal void Send() 
     {
          // Invoked by your command class
     }
}

本示例为此命令创建了一个新类。多次完成此操作后，您可能会看到一个模式，并将其包装在通用实用程序类中。有关示例，请参见 http://www.wpftutorial.net/delegatecommand.html ，或使用任何众多的WPF扩展库。

This example creates a new class just for this one command. After you've done this more than once you'll probably see a pattern, and wrap it up in a generic utility class. See http://www.wpftutorial.net/delegatecommand.html for an example, or use any of the myriad of WPF extension libraries.

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