Get the name of a method using an expression

Question

I know there are a few answers on the site on this and i apologize if this is in any way duplicate, but all of the ones I found does not do what I am trying to do.

I

Answer 1

The following is compatible with .NET 4.5:

public static string MethodName(LambdaExpression expression)
{
    var unaryExpression = (UnaryExpression)expression.Body;
    var methodCallExpression = (MethodCallExpression)unaryExpression.Operand;
    var methodCallObject = (ConstantExpression)methodCallExpression.Object;
    var methodInfo = (MethodInfo)methodCallObject.Value;

    return methodInfo.Name;
}

You can use it with expressions like x => x.DoSomething, however it would require some wrapping into generic methods for different types of methods.

Here is a backwards-compatible version:

private static bool IsNET45 = Type.GetType("System.Reflection.ReflectionContext", false) != null;

public static string MethodName(LambdaExpression expression)
{
    var unaryExpression = (UnaryExpression)expression.Body;
    var methodCallExpression = (MethodCallExpression)unaryExpression.Operand;
    if (IsNET45)
    {
        var methodCallObject = (ConstantExpression)methodCallExpression.Object;
        var methodInfo = (MethodInfo)methodCallObject.Value;
        return methodInfo.Name;
    }
    else
    {
        var methodInfoExpression = (ConstantExpression)methodCallExpression.Arguments.Last();
        var methodInfo = (MemberInfo)methodInfoExpression.Value;
        return methodInfo.Name;
    }
}

Check this sample code on Ideone. Note, that Ideone does not have .NET 4.5.