|
|
|
|
|
|
|
application may suddenly vanish, or other bizarre behavior may appear in your application. |
|
|
|
|
|
|
|
|
The sample code below shows you how to correctly handle the DEVMODE structure in the DocumentProperties call: |
|
|
|
 |
|
|
|
|
Dim hPrinter&
Dim res&
Dim dmIn As DEVMODE
Dim dmOut As DEVMODE
Dim DevmodeLength As Long |
|
|
|
|
|
|
|
|
We allocate two dynamic byte buffers to hold the DEVMODE structure and the printer's private data: |
|
|
|
|
|
|
|
|
Dim dmInBuf() As Byte
Dim dmOutBuf() As Byte
' Non-zero on success
res = OpenPrinter(Printer.DeviceName, hPrinter, 0)
If res = 0 Then
lblStatus.Caption = "Printer could not be opened"
Exit Sub
End If |
|
|
|
|
|
|
|
|
The DocumentProperties function returns the length of the necessary buffer if you set the fMode parameter to 0. This length is used to dimension the two byte arrays: |
|
|
|
|
|
|
|
|
' Get the length of the DEVMODE structure for this printer
DevmodeLength = DocumentProperties(hwnd, hPrinter, _
Printer.DeviceName, VarPtr(dmOut), VarPtr(dmIn), 0)
lblComment.Caption = "The DEVMODE structure for this printer is " _
& DevmodeLength & " bytes. " & _
"The standard DEVMODE structure is " & Len(dmOut) & " bytes."
ReDim dmInBuf(DevmodeLength)
ReDim dmOutBuf(DevmodeLength)
Pass a pointer to the start of the byte arrays as the DEVMODE parameters.
' Load the dmOutBuf buffer with the data
res = DocumentProperties(hwnd, hPrinter, Printer.DeviceName, _
VarPtr(dmOutBuf(0)), VarPtr(dmInBuf(0)), DM_OUT_BUFFER Or DM_IN_PROMPT) |
|
|
|
|
|