Find Window Question

[Newbie Coder]

Hello Group

I am trying to find a window using the known classname, which I got through
Spy++

The classname is'AfxWnd80s' & when I use FindWindow API to return the INT32
with the window handle it returns 0 (zero)

Example:

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA"
(ByVal lpClassName As String, ByVal lpWindowName As String) As Int32

Dim i As Int32 = FindWindow("AfxWnd80s", VbNullString)

MessageBox.Show(i.ToString)

This window displays maybe once a week so, I will have a long wait in which
to test it

Any Ideas?

TIA

Newbie Coder

 

[Tom Shelton]

Hello Group

I am trying to find a window using the known classname, which I got through
Spy++

The classname is'AfxWnd80s' & when I use FindWindow API to return the INT32
with the window handle it returns 0 (zero)

Example:

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA"
(ByVal lpClassName As String, ByVal lpWindowName As String) As Int32

Private Declare Auto Function FindWindow Lib "user32" _
(Byval lpClassName As String, ByVal lpWindowName As String) As IntPtr

Don't alias API calls anymore. That is a relic of the bad old days of VB6
when VB could not call unicode api calls directly. Just declare the function
Auto. The .NET marshaller is smart enough to figure out the proper function
to call on the current platform. If you alias to the "A" function on a NT
based platform (NT, 2000, XP, etc) - you are causing the runtime way more work
then is necessary, because it will first convert your string from it's unicode
format to ansi, and then pass that buffer to the api call. The api call will
promptly convert the ansi string it was passed to unicode and delegate the
call to the "W" function. The situation is even worse if the api call
actually modifies the string (which this one doesn't)... Because then that whole process has to be
reversed on top of the fact that because you used a system.string to recieve
the buffer rather then a system.text.stringbuilder, the vb.net marshaler get's
involved to cover your butt from the fact that strings are immutable. In
fact, using system.string as a api buffer will not work correctly in C#
because it doesn't cover for you

Dim i As Int32 = FindWindow("AfxWnd80s", VbNullString)

Dim i As IntPtr = FindWindow ("AfxWnd80s", Nothing)

 

[Newbie Coder]

Thanks for your reply, but your code returns zero because I tried it before
I posted the question

All you have done is changed my Int32 to IntPtr

However, I know the Marshall... but I was knocking togething a 2 min program
I thought, but was wrong. Plus I have a VB background stending from VB 3

It seems that the class I have to get is nested within another class

So, I used FindWindow to get parent & then FindWindowEx passing the handle
from the FindWindow as the first parameter.

Example:

Dim i as Int32 = FindWindow("[class name here]", VbNullString)

Dim ii as Int32 = FindWindowEx(i, 0, "AfxWnd80s", VbNullString)

MessageBox.Show(ii.ToString) returns the wrong handle because there are more
than one control with the 'AfxWnd80s' class

Any ideas?