GCHandle to Convert Bitmap to IntPtr

[xblshun]

I need help doing this. I have some source code to do so but I'm lost on 1 part of it. Look below..."Whatever" would be the bitmap but I'm lost on the "Some API Call" part. What API call would I need there?

Dim gch As GCHandle 
Try gch = GCHandle.Alloc(whatever, GCHandleType.Pinned) 
SomeAPICall(gch.AddressOfPinnedObject()) 
Finally 
If GCHandle.IsAllocated() 
Then GCH.Free() 
End Try

[ForumAccount]

"SomeAPICall" would be where you pass in the address of your now pinned bitmap to whatever API you wanted to use it with. It is not crucial to the pinning process, it's merely showing that you can now use that memory address.

[xblshun]

My goal with this is as follows, to write it to native resources as a bitmap and not as a byte array. Here's my code, maybe you can help...

Imports System.Runtime.InteropServices
Module WR    
Private Function ToPtr(ByVal data As Object) As IntPtr        
Dim h As GCHandle = GCHandle.Alloc(data, GCHandleType.Pinned)        
Dim ptr As IntPtr        
Try            
ptr = h.AddrOfPinnedObject()        
Finally            
h.Free()        
End Try        
Return ptr    
End Function    

<DllImport("kernel32.dll", SetLastError:=True)> _    
Private Function UpdateResource(ByVal hUpdate AsIntPtr, ByVal lpType As String, ByVal lpName As String, ByVal wLanguage As UShort, ByVal lpData As IntPtr, ByVal cbData As UInteger) As Boolean    
End Function    
<DllImport("kernel32.dll", SetLastError:=True)> _    
Private Function BeginUpdateResource(ByVal pFileName As String, <MarshalAs(UnmanagedType.Bool)> ByVal bDeleteExistingResources As Boolean) As IntPtr    
End Function    
<DllImport("kernel32.dll", SetLastError:=True)> _    
Private Function EndUpdateResource(ByVal hUpdate As IntPtr, ByVal fDiscard As Boolean) As Boolean    
End Function    

Public Function WriteRes(ByVal filename As String, ByVal bytes As Byte()) As Boolean        
Try            
Dim handle As IntPtr = BeginUpdateResource(filename, False)            
Dim file1 As Byte() = bytes            
Dim fileptr As IntPtr = ToPtr(file1)            
Dim res As Boolean = UpdateResource(handle,"RT_BITMAP", "0", 0, fileptr, Convert.ToUInt32(file1.Length))            
EndUpdateResource(handle, False)        
Catch ex As Exception            
Return False        
End Try        
Return True    
End Function
End Module

[dunfiddlin]

And you don't want to use a VB resource file because ... ?

[xblshun]

Because it's already a precompiled exe and I'm not using codedom...

[Niya]

I don't think that would work. What you're trying to would actually pass the address of the manged Bitmap object. I really don't expect the Windows kernel to know what to do with that since among other reasons, the kernel predates the .Net framework by eons. It is probably expecting either an hBitmap or DIBSection for image resources.

That being said. This type of thing could get pretty complicated and have some nasty bugs if you don't get it right in some places even when you know what you're doing. Why do you want to do such a thing anyway ? What problem is this meant to solve ?