Need help converting parameters from vb4 example into .NET type

Need help converting parameters from vb4 example into .NET type

• tvenhaus

  Try this:

  <[In](), Out()> ByVal MsgArea() As Char

  
  

• GeorgeOu

  You'll need the MarshalAs attribute on the arrays in the structures. Something like:
  
  Public Structure ShowBuffer
  Public Version As Integer
  ...
  <MarshalAs(UnmanagedType.ByValArray, SizeConst:=7)> _
  Public reserved() As Integer
  End Structure
  
  
  
  

• Squirrelz

   

  See this screenshot.>>

  http://i13.photobucket.com/albums/a272/u-might-want-this/Structure-ScreenShot.jpg

  '-------------------------START OF CODE-----------------------------

  Structure personalDetails

  <VBFixedString(4)> Public title As String

  Public firstName As String

  Public last_orSurname As String

  Public address1 As String

  Public address2 As String

  Public region As String

  Public post_ZipCode As String

  Public telNo As Decimal

  End Structure

  '------------------------------------------------------------------------------

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

  Dim you As personalDetails

  you.title = "Mr"

  you.firstName = "Fred"

  you.last_orSurname = "Bloggs"

  you.address1 = "1 any Street"

  you.address2 = "DownTown"

  you.region = "Chicago"

  you.post_ZipCode = "54321"

  you.telNo = 5551234

  End Sub

  '-----------------------END OF CODE-----------------------------------

   

  P.S. The vbFixedString statement limits a string length to whatever you declare.

   

  Regards,

  S_DS.

   

   

  
  
  

• Toby Buckley

  If you pass the string to the DLL, then ByVal As String should work with the Ansi keyword in the function declaration. If the DLL returns a string, then pass a StringBuilder with the initial capacity set large enough to contain the returned string.
  
  
  

• howard dierking - MSFT

  The ByVal as string did not work without the ANSI for passing a string to the function, it resulted in a fatal error but adding the ANSI eliminated that. The problem is the string can still not be seen when dequeuing the message. The same thing goes for the return string from the DLL when using a Stringbuilder. Is there something in the managed/unmanaged transistion that is losing the address of the string. When sending or receiving the return status codes are successful but always with empty strings. Any other possibilites for the declare for msg_area parameter Or any other ideas
  

• Pockey

  Thanks for the help.

  The remaining problem is with the "msg_Area" parameter passed to the pams_put_msg. It is specified as

  Argument Data Type Mechanism Prototype Access

  msg_area char reference char * passed

  msg_area is defined as:

  For buffer-style messaging, supplies the address of a memory region or a message

  pointer containing the message to be delivered to the target queue of the receiver

  program.

  I am not able to get the buffer declared correctly so that data buffer is passed and readable on the receiving end. The message goes through ok based on a return status and the other parameters can be logged and verified, but the buffer appears to be empty.

  I have tried declaring it as By Val msgArea as String, ByVal msgArea as Object, ByRef msgArea as String, ByVal msgArea as Object,

  <MarshalAs(UnmanagedType.LPTStr)> using both ByVal and ByRef as Sting and ByVal and ByRef as Object,

  <MarshalAs(UnmanagedType.AsAny)> using both ByVal and ByRef as Sting and ByVal and ByRef as Object,

  <MarshalAs(UnmanagedType.VBByRefStr)> using both ByVal and ByRef as Sting and ByVal and ByRef as Object, and adding the ansi in front of the declarations as well.

  The function call is to an unmanaged .dll file from the managed VB.NET world and I believe the definition and handling of strings crossing this boundary is where the probelm is coming from.

  Please respond with any ideas.

  
  
• Need help converting parameters from vb4 example into .NET type