Using methods with reflection c#

Question

im trying to make an implementacion of a dictionary that goes Dictionary<string, Func<string[], string>> with reflection. As of right now i got it working like this

        lCommands.Add(new string[] { "help", "ayuda" }, HelpFunc);
        lCommands.Add(new string[] { "cambiacargo", "ccl" }, CambiarCargoLegislador);
        lCommands.Add(new string[] { "buscar" }, ObtenerDatosLegislador);
        lCommands.Add(new string[] { "listartiemposbloques" }, ObtenerTiemposBloques);
        lCommands.Add(new string[] { "modificartiemposbloques" }, ModificarTiempoBloque);
        lCommands.Add(new string[] { "logout" }, logout);
        lCommands.Add(new string[] { "tienepalabra", "hablado" }, TiempoPalabraActivo);

where the .Add is an extension method that takes an array of string, and a Func and make it keys for the same Func. My problem actually is that i would like to be able to this with reflection. So after searching for a while I ve been able to come up with this

   foreach (MethodInfo methodInfo in typeof(CommandHelper).GetMethods(BindingFlags.NonPublic | BindingFlags.Static))
    {
        string methodName = methodInfo.Name;

        object[] attribute = methodInfo.GetCustomAttributes(typeof(Command), true);

        if (attribute.Length > 0)
        {
            Command myAliases = (Command)attribute[0];

            lCommands.Add(myAliases.alias, /* here is my problem propertyInfo.Name*/);
        }
    }

but im not sure how to transform the methodInfo into a Func<string[],string>. To sum it up, i want to do the same for the first chunk of code with reflection

Just in case someone need it this is an example of one of the functions

    [Help(Remainder = "Obtiene el tiempo hablado por un legislador")]
    [Command("tienepalabra,hablado,tpa")]
    private static string TiempoPalabraActivo(string[] arg)
    {
        LegisladorService leServ = new LegisladorService();
        try
        {
            return $"el legislador {leServ.TraerPorIdNombreApellido(Form1._server.tienePalabra)} estuvo hablando durante {Form1._server.TiempoPalabra()}";
        }
        catch (Exception)
        {
            return "No hay legislador con palabra activo";
        }
    }

Thanks in advance

Morris Janatzek · Accepted Answer · 2019-01-22T15:30:21.307

0

You can call .Invoke on the method info to execute the method.

This can be wrapped into a Func:

Func<string[],string> func = (parameters) => methodInfo.Invoke(null, new object[] { parameters });

edited Jan 22 '19 at 15:30

answered Jan 22 '19 at 14:34

Morris Janatzek

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3
11

this is not working, i forgot to mention this is static, but even with methodInfo.invoke(null, parameters) its still saying i cannot use lambda function with an implicit type – nalnpir Jan 22 '19 at 14:41
Sorry. Forgot that lambdas cannot assigned to var. – Morris Janatzek Jan 22 '19 at 14:43
Yeah i thought to do that, but the dictionary remains empty whenever i call one of the keys it does nothing :/. Although i dont have an obj since its a static method – nalnpir Jan 22 '19 at 14:51
To use null as a first parameter for a static class is correct. – Morris Janatzek Jan 22 '19 at 15:19
yeah now its working although i hit a wall when parameters are null, any ideas i got this code Func func = (parameters) => { try { return (string)methodInfo.Invoke(null, parameters); } catch (ArgumentException) { return (string)methodInfo.Invoke(null, null); } }; – nalnpir Jan 22 '19 at 15:28
When calling invoke parameters has to always be an array. So you actually need an array in an array. I updated the answer – Morris Janatzek Jan 22 '19 at 15:32

Using methods with reflection c#

1 Answers1