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How to Instantiate a Class a runtime from a String value

Paul Chase — Thu, 26 Oct 2006 15:44:02 GMT

I remember seeing how to do this using reflection but cannot remember how it was done. Below is psuedo code of what I want to do.

public sub whatever(classname as string)

dim something as new classname

end sub

Thanks

Paul

RE: How to Instantiate a Class a runtime from a String value

Trent L. Taylor — Thu, 26 Oct 2006 15:44:02 GMT

Ivan,

You made me laugh :hehe: Your posts are always enjoyable to read! :)

RE: How to Instantiate a Class a runtime from a String value

Ivan George Borges — Thu, 26 Oct 2006 15:16:21 GMT

[quote][b]Paul Chase (10/26/2006)[/b][hr]Don't worry Ivan i have full faith that as soon as we get comfortable using .net MS will throw something new at us to learn.:)[/quote]

Should I seet and wait then?:P

[quote]Reflection seems like macro substitution "&" in foxpro but on steriods.[/quote]

Oh, good to know. I will certainly bump into it soon.

[quote]Now I am struggling with type converters.[/quote]

Don't think you're allowed to swear in the forum!

RE: How to Instantiate a Class a runtime from a String value

Paul Chase — Thu, 26 Oct 2006 14:23:26 GMT

:D You have that right!!

RE: How to Instantiate a Class a runtime from a String value

Trent L. Taylor — Thu, 26 Oct 2006 13:55:57 GMT

[quote]Reflection seems like macro substitution "&" in foxpro but on steriods.[/quote]

You are exactly right here...just a much better strong-typed version that is not as likely to blow your fingers off when you use it :)

RE: How to Instantiate a Class a runtime from a String value

Paul Chase — Thu, 26 Oct 2006 13:54:10 GMT

Don't worry Ivan i have full faith that as soon as we get comfortable using .net MS will throw something new at us to learn.:)

Reflection seems like macro substitution "&" in foxpro but on steriods.

Now I am struggling with type converters.

RE: How to Instantiate a Class a runtime from a String value

Ivan George Borges — Thu, 26 Oct 2006 11:42:13 GMT

Right ... after understanding Serialization, this is my next challenge.:hehe:

RE: How to Instantiate a Class a runtime from a String value

StrataFrame Team — Thu, 26 Oct 2006 08:16:11 GMT

No problem :)

Reflection is fun because you can do literally ANYTHING with it... access private members, create instances of private types, etc.; you can even use the stuff within the Emit namespace to create dynamic types, methods, and assemblies. However, you'll want to try to use it as sparingly as possible because it is slow... in fact, it's even slower than late binding, but there are times when it is unavoidable. We go to great lengths within the framework to avoid the use of reflection where ever possible (hence the creation of the property descriptors within the business object... if you don't use them, then .NET uses reflection to accomplish all of the binding tasks).

RE: How to Instantiate a Class a runtime from a String value

Paul Chase — Thu, 26 Oct 2006 07:48:22 GMT

Thanks Ben,

That was what I was looking for! Once I seen it the light came on. Thanks man

Paul

RE: How to Instantiate a Class a runtime from a String value

StrataFrame Team — Wed, 25 Oct 2006 16:13:51 GMT

Here ya go... If you end up doing a lot of reflection, you'll probably want to import System.Reflection...

Private Sub DoSomething(ByVal ClassName As String, ByVal MethodName As String)
'-- Establish locals
Dim loObject As Object
Dim loType As Type
Dim loMethod As Reflection.MethodInfo

'-- Get the type
loType = Type.GetType(ClassName)

'-- Create the object
loObject = Activator.CreateInstance(loType)

'-- Get the method
loMethod = loType.GetMethod(MethodName)

'-- Execute the method
loMethod.Invoke(loObject, Nothing)
End Sub

You can also use the Object Browser in visual studio and look at everything in the System.Reflection namespace. You'll get lots of ideas of what you might want to do :)