提取前pression树法的名字吗？ [英] Extract method name from expression tree?

问题描述

我想实现以下模式功能：

I am trying to implement the following pattern function:

MethodInfo GetMethod(      
  Expression<Func<TTarget, EventHandler<TEventArgs>>> method)

如果需要，我可以提供TTarget的实例

I can provide an instance of TTarget if required

所需的用法是：

public static void Main(string[] args)
{
    var methodInfo = GetMethod<Program, EventArgs>(t => t.Method);
    Console.WriteLine("Hello, world!");
}

private void Method(object sender, EventArgs e)
{
}

下面是我到目前为止已经试过：

Here's what I've tried so far:

private static MethodInfo GetMethod(TTarget target, Expression<Func<TTarget, EventHandler<TEventArgs>>> method)
{
  var lambda = method as LambdaExpression;
  var body = lambda.Body as UnaryExpression;
  var call = body.Operand as MethodCallExpression;
  var mInfo = call.Method as MethodInfo;

  Console.WriteLine(mInfo);

  throw new NotImplementedException();
}

它打印出来：

It prints out:

System.Delegate CreateDelegate（System.Type的，System.Object的，System.Reflection.Met hodInfo）

System.Delegate CreateDelegate(System.Type, System.Object, System.Reflection.Met hodInfo)

推荐答案

你成功了一半。 看看下面

You're half way there. Look at the code below

public static void Main(string[] args)
{
    var program = new Program();
    var methodInfo = GetMethod<Program, EventArgs>(()=> program.Method);
    Console.WriteLine(methodInfo.Name);
}

和使用下面的code，以获得方法名。

And use the following code to get the method name.

static MethodInfo GetMethod<TTarget, TEventArgs>(Expression<Func<EventHandler<TEventArgs>>> method) where TEventArgs:EventArgs
{
    var convert = method.Body as UnaryExpression;
    var methodCall = (convert.Operand as MethodCallExpression);
    if (methodCall != null && methodCall.Arguments.Count>2 && methodCall.Arguments[2] is ConstantExpression)
    {
        var methodInfo = (methodCall.Arguments[2]as ConstantExpression).Value as MethodInfo;
        return methodInfo;
    }
    return null;
}

我希望这回答了你的问题。

I hope this answers your question.

这篇关于提取前pression树法的名字吗？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！