What is the VB equivalent of Java's instanceof and isInstance()?

brasskazoo picture brasskazoo · Jun 17, 2009 · Viewed 13.8k times · Source

In the spirit of the c# question..

What is the equivalent statements to compare class types in VB.NET?

Answer

Andrew Backer picture Andrew Backer · Jun 17, 2009

Are you looking for something like TypeOf? This only works with reference types, not int/etc.

If TypeOf "value" Is String Then
     Console.WriteLine("'tis a string, m'lord!")

Or do you want to compare two different instances of variables? Also works for ref types:

Dim one As Object = "not an object"
Dim two As Object = "also not an object, exactly"
Dim three as Object = 3D

If one.GetType.Equals( two.GetType ) Then WL("They are the same, man")
If one.GetType Is two.GetType then WL("Also the same")
If one.GetType IsNot three.GetType Then WL("but these aren't")

You could also use gettype() like thus, if you aren't using two objects:

If three.GetType Is gettype(integer) then WL("is int")

If you want to see if something is a subclass of another type (and are in .net 3.5):

If three.GetType.IsSubclassOf(gettype(Object)) then WL("it is")

But if you want to do that in the earlier versions, you have to flip it (weird to look at) and use:

If gettype(Object).IsAssignableFrom(three.GetType) Then WL("it is")

All of these compile in SnippetCompiler, so go DL if you don't have it.