CreateWindowEx

[ashthud]

This is a vb6 slash win api problem:

I am creating a win32 dll in vb6 (which *is* possible btw:

http://windowsdevcenter.com/pub/a/windows/2005/04/26/create_dll.html).

Basically the dll's purose is to paint a control on screen:
1) initiate common control (initcommoncontrolsex)
2) create window (createwindowex)
NB: i send the window handle of the vb form as a parameter

I want the dll to draw the window/control on my vb form...
* I can directly call 1) and 2) from my vb app and paint a control
* I can directly call 1) and 2) from my vb app and paint a control to another form
* I CAN'T call 1) and 2) from dll (with my vb app handle) to paint the control

(I don't have the code available on me so i will post that later today maybe)

 

[ashthud]

Correction: I can actually initialize the common control (1) with the dll; it returns true... but createwindowex(2) only returns 0... as in DIDN'T WORK!

 

[strongm]

And what did GetLastError tell you?

 

[ashthud]

This is the code in the dll:

Public Function CreateWindow(oControl As icc, oClass As String, oName As String, oHwnd As Long, oDWStyle As Long) As Long
   InitCommonControlsEx oControl
   CreateWindow=CreateWindowExA(0,oClass,oName,oDWStyle,0,0,10,10,oHwnd,0,0,0)
   MsgBox GetLastError()
End Function

This is the code to call it:

Private Type icc
   osize As Long
   oicc As Long
End Type
dim t as icc
t.osize = 8
t.oicc = 2
CreateWindow(t, "SysTreeView32", "TV", Me.hWnd, WS_VISIBLE + WS_BORDER + WS_CHILD)

The getlasterror returns 0.

Ashthud

 

[Hypetia]

>The getlasterror returns 0.
GetLastError won't tell anything. You need to check Err.LastDllError property.

 

[ashthud]

Error number is 1407... im going to have quick google around and see what i can find

Ashthud

 

[ashthud]

Ok, apparently the 1407 error is related to an incorrect class name...
the value i sent to the dll was "SysTreeView32", but ends up being something stupid like: "??????2". Do dlls have a problem handling strings?

Ashthud

 

[ashthud]

I solved the problem; because my dll has no advanced string handling technique, i have to pass any string values using the strconv() function and convert a string value to unicode string value:

StrConv("SysTreeView32", vbUnicode)

Ashthud

 

[ashthud]

Is there any reason why i can use my dll in VB6 but cannot use it in FOXPRO (2.6)? I get a "ACCESS VIOLATION ERROR"

Ashthud