UnityEngine.BoxCollider != typeof(UnityEngine.BoxCollider) Why?

Questions & Answers
1

C# Code:

typeof(UnityEngine.BoxCollider) ==> print:UnityEngine.BoxCollider

BoxCollider[] hinges = FindObjectsOfType(typeof(UnityEngine.BoxCollider)) as BoxCollider[]; ==>is right

But

BoxCollider[] hinges = FindObjectsOfType(UnityEngine.BoxCollider) as BoxCollider[]; ==>this is wrong???Why

** error CS0119: Expression denotes a `type', where a`variable', `value' or`method group' was expected error CS1502: The best overloaded method match for `UnityEngine.Object.FindObjectsOfType(System.Type)' has some invalid arguments

error CS1503: Argument `#1' cannot convert`object' expression to type `System.Type' **

UnityEngine.BoxCollider!=typeof(UnityEngine.BoxCollider) ???? why

2

It's just the way the language works. FindObjectsOfType() takes as an argument an object of type System.Type. BoxCollider is a different type, so it can't be used as the argument.

I'm guessing what you're looking is a generic version of the function, e.g.:

...FindObjectsOfType<BoxCollider>()...

Unfortunately though, there is no generic version of FindObjectsOfType (at least not AFAIK).

3

Like Jesse said there is no build in generic version of this function(s), but you can create your own if you really want ;)

public class MyTools 
{
    public static T FindObjectOfType<T>() where T : UnityEngine.Object
    {
        return (T)UnityEngine.Object.FindObjectOfType(typeof(T));
    }

    public static T[] FindObjectsOfType<T>() where T : UnityEngine.Object
    {
        return (T[])UnityEngine.Object.FindObjectsOfType(typeof(T));
    }    
}

You can use them like all the other generic functions:

BoxCollider[] C = MyTools.FindObjectsOfType<BoxCollider>();

EDIT

Just some more information on System.Type:

System.Type is the base class for reflection. Here is a short article about reflection:

http://www.codeguru.com/csharp/csharp/cs_misc/reflection/article.php/c4257

System.Type is a special class that is used to describe any other classes or types. The typeof() operator returns the Type instance that describes the type of your argument.

If you use Visual C# thanks to Intellisense you can see all members of the Type class.

To get the Type instance of a certain type just use:

System.Type type = typeof(BoxCollider);

Now you can use the type to get a list of all members or functions that are included in the BoxCollider class, or get the name of the class as string.

I'll hope that explains a bit what System.Type is and hopefully you get the difference between BoxCollider and typeof(BoxCollider).