C# 委托 System.Action 不接受 1 个参数
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Delegate System.Action does not take 1 arguments
提问by idish
The action :
那个行动 ：
readonly Action _execute;
public RelayCommand(Action execute)
: this(execute, null)
{
}
public RelayCommand(Action execute, Func<Boolean> canExecute)
{
if (execute == null)
throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
Other class's code:
其他类的代码：
public void CreateCommand()
{
RelayCommand command = new RelayCommand((param)=> RemoveReferenceExcecute(param));}
}
private void RemoveReferenceExcecute(object param)
{
ReferenceViewModel referenceViewModel = (ReferenceViewModel) param;
ReferenceCollection.Remove(referenceViewModel);
}
Why do I get the following exception, how can I fix it?
为什么会出现以下异常，我该如何解决？
Delegate 'System.Action' does not take 1 arguments
委托“System.Action”不接受 1 个参数
采纳答案by J0HN
System.Actionis a delegate for parameterless function. Use System.Action<T>.
System.Action是无参数函数的委托。使用System.Action<T>.
To fix this, replace your RelayActionclass with something lie the following
要解决此问题，请RelayAction用以下内容替换您的课程
class RelayAction<T> {
readonly Action<T> _execute;
public RelayCommand(Action<T> execute, Func<Boolean> canExecute){
//your code here
}
// the rest of the class definition
}
Note RelayActionclass should become generic. Another way is to directly specify the type of parameter _executewill receive, but this way you'll be restricted in usage of your RelayActionclass. So, there are some tradeoff between flexibility and robustness.
注意RelayAction类应该变成通用的。另一种方法是直接指定_execute将接收的参数类型，但这样您将限制使用您的RelayAction类。因此，在灵活性和健壮性之间存在一些权衡。
Some MSDN links:
一些 MSDN 链接：
回答by Trinitron
You can define your command 'RemoveReferenceExcecute' without any parameters
您可以在没有任何参数的情况下定义您的命令“RemoveReferenceExcecute”
RelayCommand command = new RelayCommand(RemoveReferenceExcecute);}
or you can pass some parameters / objects into it:
或者您可以将一些参数/对象传递给它：
RelayCommand<object> command = new RelayCommand<object>((param)=> RemoveReferenceExcecute(param));}
In the second case do not forget to pass CommandParameter from your view;
在第二种情况下，不要忘记从您的视图中传递 CommandParameter；
