Topic: Device Context Handle

[Draftek]

I'm writing an activex dll that accepts a drawing file or url and returns a Bitmap handle so I can populate a listview control with various drawing previews of my choice.

The problem is, in order to use the win32 api function: CreateCompatibleBitmap() I need the hDc of some graphics containing object which my dll does not contain.

I see two options since I can't figure out how to push NULL in VB:
1. I create an object in code and create a new hdc like this:

Code: [Select]

Private hDc As Long
Private oPic As Picture
Private Sub Class_Initialize()
    Set oPic = New StdPicture
    hdc = GetDC(oPic.Handle)
End Sub

or change my mind and just make a simple usercontrol that I only want to get the hDc with the hDc built in.

Is there anything wrong with option number 1?

[Draftek]

*pin drop in the back leaves deafening sound....*

[Draftek]

okay, one Ramification of option number 1 just occured to me:

If the com class is destroyed before the calling app uses the handle to create the bitmap then I guess that should cause an exception since the pointer is gone.

So, what about forcing the calling app to pass an hDc for use?

[David Hall]

*pin drop in the back leaves deafening sound....*

I'm still on my first cup of coffee, so that pin drop was really loud