Get generic type from parameter

Question

Im making a XNA contentloader:

public object[] LoadIt(KeyValuePair<Type,string>[] resources, ContentManager content)
{
    object[] result = new object[resources.Length];
    for(int i=0;i<result.Length;i++)
    {
        result[i] = content.Load<resources[i].Key>(resources[i].Value);
    }
    return result;
}

but apparenty you're not allowed to pass a generic type from a variable, so how do i solve this then?

also if you pass the type as a generic to the method itself, then i still need the object calling the method to get the type from variable, since ill be making a file that declares the files to load and from the strings of that file, i need to pass the type and path of the files to load

One way is to call the method using reflection: http://stackoverflow.com/a/232621/869621 — Kevin Gosse, Jun 25 '13 at 11:03
Load Method: http://msdn.microsoft.com/en-us/library/bb197848.aspx — Andre, Jun 25 '13 at 11:24
Quesion has been asked before http://stackoverflow.com/questions/2100760/can-i-pass-a-type-object-to-a-generic-method — Daniel Johnson, Jun 26 '13 at 00:02
possible duplicate of [How to use reflection to call generic Method?](http://stackoverflow.com/questions/232535/how-to-use-reflection-to-call-generic-method) — nawfal, Jan 17 '14 at 15:42

score 1 · Answer 1 · answered Jun 25 '13 at 11:50

This is an XNA-specific answer to your question, but you don't need to do that!

You could just replace this:

content.Load<resources[i].Key>(resources[i].Value);

With this:

content.Load<object>(resources[i].Value);

XNA figures out the appropriate type on its own at runtime, from the content file itself. The generic is just for convenience and type safety.

If you wanted to verify the type of the loaded object for yourself, you could do something like this:

if(result[i].GetType() != resources[i].Key
        && !result[i].GetType().IsSubclassOf(resources[i].Key))
{
    throw new InvalidOperationException();
}

Of course, one could ask why you are making a "contentloader"? I don't have enough information about what you are doing - but it looks like it might be unnecessary. XNA's ContentManager already implements (customisable) caching of loaded objects - so it's likely that you could (and should) just use it directly.

I thought his reasoning may have been for dynamic content for a dynamic object. — Daniel Johnson, Jun 26 '13 at 00:05
@ShahroozJefri [Revenge](http://stackoverflow.com/a/17638864/165500) downvote on a random answer of mine? Stay classy. — Andrew Russell, Jul 14 '13 at 11:24

score 0 · Answer 2 · answered Jun 25 '13 at 11:05

You simply can't as the type is not compile-time constant.

What you can do is to use reflection without a problem as you only need object as return value:

public object[] LoadIt(KeyValuePair<Type,string>[] resources, ContentManager content)
{
    object[] result = new object[resources.Length];
    for(int i=0;i<result.Length;i++)
    {
        result[i] = content
                      .GetType()
                      .GetMethod("Load")
                      .MakeGenericMethod(resources[i].Key)
                      .Invoke(content, new object[] { resources[i].Value });
    }
    return result;
}

Get generic type from parameter

2 Answers2