如何在C#中实现按名称调用？

Question

谁能告诉我如何在C#中实现按名称调用？

Answer 1

传递 lambda 函数而不是值。 C# 是急切评估的，因此为了推迟执行，以便每个站点重新评估提供的参数，您需要将参数包装在函数中。

int blah = 1;

void Foo(Func<int> somethingToDo)  {
  int result1 = somethingToDo(); // result1 = 100

  blah = 5;
  int result2 = somethingToDo(); // result = 500
}

Foo(() => blah * 100);

如果您使用 .NET 4.0，则可以使用 Lazy 类获得类似（但不相同）的效果。 Lazy 会记住结果，以便重复访问时不必重新评估函数。

Answer 2

public enum CallType
{
/// <summary>
/// Gets a value from a property.
/// </summary>
Get,
/// <summary>
/// Sets a value into a property.
/// </summary>
Let,
/// <summary>
/// Invokes a method.
/// </summary>
Method,
/// <summary>
/// Sets a value into a property.
/// </summary>
Set
}

/// <summary>
/// Allows late bound invocation of
/// properties and methods.
/// </summary>
/// <param name="target">Object implementing the property or method.</param>
/// <param name="methodName">Name of the property or method.</param>
/// <param name="callType">Specifies how to invoke the property or method.</param>
/// <param name="args">List of arguments to pass to the method.</param>
/// <returns>The result of the property or method invocation.</returns>
public static object CallByName(object target, string methodName, CallType callType, params object[] args)
{
  switch (callType)
  {
    case CallType.Get:
      {
        PropertyInfo p = target.GetType().GetProperty(methodName);
        return p.GetValue(target, args);
      }
    case CallType.Let:
    case CallType.Set:
      {
        PropertyInfo p = target.GetType().GetProperty(methodName);
        p.SetValue(target, args[0], null);
        return null;
      }
    case CallType.Method:
      {
        MethodInfo m = target.GetType().GetMethod(methodName);
        return m.Invoke(target, args);
      }
  }
  return null;
}

Answer 3

您可以使用反射来做到这一点：

using System;
using System.Reflection;

class CallMethodByName
{
   string name;

   CallMethodByName (string name)
   {
      this.name = name;
   }

   public void DisplayName()      // method to call by name
   {
      Console.WriteLine (name);   // prove we called it
   }

   static void Main()
   {
      // Instantiate this class
      CallMethodByName cmbn = new CallMethodByName ("CSO");

      // Get the desired method by name: DisplayName
      MethodInfo methodInfo = 
         typeof (CallMethodByName).GetMethod ("DisplayName");

      // Use the instance to call the method without arguments
      methodInfo.Invoke (cmbn, null);
   }
}

Answer 4

如果您的意思是这个，那么我认为最接近的等价物是代表。

Answer 5

为什么不使用

Microsoft.VisualBasic.Interaction.CallByName