Question

While there are similar questions in Stackoverflow about this it does not help me with my problem.
Here is the big picture of what I am doing. I am generating IL for my iDB2DataReader to dynamically get my types from a database and map to my poco.
I am having problems getting a nullable to pull in the data.

So I have a method that needs to return the methodinfo via reflection. To get the this I am using “getmethod” of the type that I need.
Here is the code:

private static MethodInfo GetDataMethod(Type destinationDataType, Type underlyingDestinationDataType, iDB2DataReader reader)
{
    MethodInfo methInfo = null;

    if (_readerDataMethods.ContainsKey(destinationDataType))
    {
        methInfo = _readerDataMethods[destinationDataType];
    }
    else
    {

        if (underlyingDestinationDataType != null)
        {
            //trying to get underlying type which would be DateTime thus resulting in GetDatetime.
            methInfo = reader.GetType().GetMethod("Get" + underlyingDestinationDataType.Name);
        }
        else
            methInfo = reader.GetType().GetMethod("Get" + destinationDataType.Name);
        //methInfo = reader.GetType().GetMethod("Get" + destinationDataType.ToGenericTypeString());

        if (methInfo != null)
        {
            _readerDataMethods[destinationDataType] = methInfo;
        }
    }

    return methInfo;
}

As you can see from my code comment I get the underlying type of datetime but this does not work, it gets a runtime error of “Operation could destabilize the runtime.”.

The real problem is I don’t know what the name I should be using for the getmethod for a Nullable<DateTime>. Or at least I was hoping it was that simple. Any help would be appreciated.

Answer 1

You’re probably going to have to create a special case fur Nullables as the actual type name wouldn’t be valid in a method name. I’d check to see if it’s a Nullable type and the use reflection to get the generic parameter.

Example:

Type t = typeof (Nullable<DateTime>);

Console.WriteLine(t.Name);   // Nullable`1
if (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>))
{
    Type t2 = Nullable.GetUnderlyingType(t);
    Console.WriteLine("Nullable"+t2.Name); // NullableDateTime
}