I use VB in VS2010
I am attempting to print the contents of a RichTextBox using the EM_FORMATRANGE message.
I am using code that appears often in posts about this topic.
The API call is:
Private Declare Function SendMessage Lib "user32" Alias _
"SendMessageA" (ByVal hWnd As Long, ByVal msg As Long, ByVal wp As Long, ByVal lp As Long) As Long
The codeline that sends the message is:
nNextCharPos = SendMessage(MyText.Handle, EM_FORMATRANGE, wparam, lparam)
nNextCharPos, SendMessage, EM_FORMATRANGE are all declared as long
MyText is IntPtr
wparam, and lparam are all declared as IntPtr as follows
Dim wparam As IntPtr = New IntPtr(1)
Dim lparam = Marshal.AllocCoTaskMem(Marshal.SizeOf(fr))
Marshal.StructureToPtr(fr, lparam, False)
The code fails with the message .... unbalanced stack ..... possibly due to signature mismatch ....
If I try
nNextCharPos = SendMessage(clng(MyText.Handle), EM_FORMATRANGE, clng(wparam), clng(lparam))
I get the same message
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I have also tried re-declaring SendMessage as
Private Declare Function SendMessage Lib "user32" Alias _
"SendMessageA" (ByVal hWnd As IntPtr, ByVal msg As IntPtr, ByVal wp As IntPtr, ByVal lp As IntPtr) As IntPtr
and declaring nNextCharPos as IntPtr
with the codeline
nNextCharPos = SendMessage(MyText.Handle, cInt(EM_FORMATRANGE), wparam), lparam)
and this time the error message comes out as Trying to read or write to protected memory.
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So I am stuck.
Can anyone help?
Thanks
ME
