Pass concrete object type as parameter for generic method

Question

I have an API using generic method as follow

public static class DataProvider
{
    public static Boolean DeleteDataObject<T>(Guid uid, IDbConnection dbConnection)
    {
        // Do something here
    }

    public static IDbConnection GetConnection()
    {
        // Get connection
    }
}

My application contains classes generated using CodeDOM at runtime, and in order to keep track of I created an interface called IDataObject. I am trying to pass the concrete type of each object to the generic method above as follow:

public static Boolean PurgeDataObject(this IDataObject dataObject, Guid uid)
{
    return DataProvider.DeleteDataObject<T>(uid, DataProvider.GetConnection());
}

dataObject contains an instance of a class that inherit from IDataObject. I am interested in getting that type and pass it as T. I am trying to find out if it is possible to somehow use dynamic here. typeof() and GetType() does not work as stated in Here

Answer 1

I suspect you want something like this:

public static Boolean PurgeDataObject(this IDataObject dataObject, Guid uid)
{
    return PurgeDataObjectImpl((dynamic) dataObject, uid);
}

private static Boolean PurgeDataObjectImpl<T>(T dataObject, Guid uid)
    where T : IDataObject
{
    return DataProvider.DeleteDataObject<T>(uid, DataProvider.GetConnection());
}

That uses dataObject dynamically, getting the "execution-time compiler" to perform type inference to work out T.

You could just use reflection to do this yourself, using MethodInfo.MakeGenericMethod - but this way is certainly less code.