How to use reflection to call method by name

Question

Hi I am trying to use C# reflection to call a method that is passed a parameter and in return passes back a result. How can I do that? I've tried a couple of things but with no success. I'm used to PHP and Python where this can be done on a single line so this is very confusing to me.

In essence this is how the call would be made without reflection:

response = service.CreateAmbience(request);

request has these objects:

request.UserId = (long)Constants.defaultAmbience["UserId"];
request.Ambience.CountryId = (long[])Constants.defaultAmbience["CountryId"];
request.Ambience.Name.DefaultText = (string)Constants.defaultAmbience["NameDefaultText"];
request.Ambience.Name.LanguageText = GetCultureTextLanguageText((string)Constants.defaultAmbience["NameCulture"], (string)Constants.defaultAmbience["NameText"]);
request.Ambience.Description.DefaultText = (string)Constants.defaultAmbience["DescriptionText"];
request.Ambience.Description.LanguageText = GetCultureTextLanguageText((string)Constants.defaultAmbience["DescriptionCulture"], (string)Constants.defaultAmbience["DescriptionDefaultText"]);

This is my function to implement the reflection where serviceAction for the case above would be "CreateAmbience":

public static R ResponseHelper<T,R>(T request, String serviceAction)
{
    ICMSCoreContentService service = new ContentServiceRef.CMSCoreContentServiceClient();
    R response = default(R);
    response = ???
}

Answer 1

Something along the lines of:

MethodInfo method = service.GetType().GetMethod(serviceAction);
object result = method.Invoke(service, new object[] { request });
return (R) result;

You may well want to add checks at each level though, to make sure the method in question is actually valid, that it has the right parameter types, and that it's got the right return type. This should be enough to get you started though.

Answer 2

Here's a quick example of calling an object method by name using reflection:

Type thisType = <your object>.GetType();
MethodInfo theMethod = thisType.GetMethod(<The Method Name>); 
theMethod.Invoke(this, <an object [] of parameters or null>); 

Answer 3

If you're on .NET 4, use dynamic:

dynamic dService = service;
var response = dService.CreateAmbience(request);

Answer 4

You can use Delegate.CreateDelegate to obtain a delegate to the method by name:

public static R ResponseHelper<T,R>(T request, string serviceAction)
{
    var service = new ContentServiceRef.CMSCoreContentServiceClient();

    var func = (Func<T,R>)Delegate.CreateDelegate(typeof(Func<T,R>),
                                                  service,
                                                  serviceAction);

    return func(request);
}