Question

I have a method

void InitAndLoadTables(DbConnection cnctn, Dictionary<string, DbTableLoadParameters> tableNamesAndParameters)

where dictionary can have any amount of tables. Every table corresponds a class.

When I iterate through all the tables I would like to call generic method

public void Init<T>(string tableName)

for all the tables. I tried to include type of the class to be property of DbTableLoadParameters as

Type ObjectType { get; set; }

and use that when calling Init. This does not work. So is it even possible to do? If the amount of tables would be fixed I could maybe make InitAndLoadTables generic like

InitAndLoadTables<T, K, V>

but it isn’t. So is only possibility to call Init elsewhere like

Init<Orders>("Orders");

Thanks & BR -Matti

Answer 1

There is no way to pass an arbitrary number of type arguments to a generic method, because a generic method always has a fixed number of type arguments.

However, you don’t even seem to need that. There is a way to call a generic method with a runtime-known type, but this involves reflection, which sounds like it’s what you’re really after:

class Program
{
    static void Main(string[] args)
    {
        var myobj = new MyClass();

        // Call MyClass.Init<Orders>
        CallMyClassInit(typeof(Orders), "tableOrders");

        // Call Init<string>
        CallMyClassInit(typeof(string), "tableString");
    }

    static void CallMyClassInit(MyClass obj, Type type, string tableName)
    {
        typeof(MyClass)
            .GetMethod("Init")
            .MakeGenericMethod(type)
            .Invoke(obj, new object[] { tableName });
    }
}

class Orders { }

class MyClass
{
    public void Init<T>(string tableName)
    {
        Console.WriteLine("I was called with type " + typeof(T) + " for table " + tableName);
    }
}

Output:

I was called with type ConsoleApplication1.Orders for table tableOrders
I was called with type System.String for table tableString