Using Winsock to send and get User Defined Types

[Coolhp]

My question goes as follows :

I am trying to "talk" to an SMS server through its TCP port. This little guy sends packets with defined structures.
I have enough documentation to recreate these structures in VB but I cant figure out how to have the Winsock Control receive such packets.

Let me give you an example :

Public Type Header_data
    Length As Integer
    CorrelationNumber As Integer
    MessageType As Byte
    Operation As Byte
    Unused As Integer
End Type

I would like to do something like :

Dim Header as Header_Data

'... (whatever)....'

Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)
    Winsock1.GetData Header
End Sub

But it seems that Winsock does not accept User Defined Type as parameter...

Is there a way to do this ???




[Edited by Coolhp on 08-20-2000 at 05:41 PM]

[Coolhp]

Ok... Here is the solution guys.

SUMMARY
The Winsock control methods SendData and GetData send and receive data through an argument declared of type variant. The following variant types are supported:

Byte vbByte
Integer vbInteger
Long vbLong
Single vbSingle
Double vbDouble
Currency vbCurrency
Date vbDate
Boolean vbBoolean
SCODE vbError
String vbString
Byte Array vbArray + vbByte

Because user-defined types are not directly supported, you must make use of the byte-array data type in order to pass a user-defined type with the Winsock control. This article demonstrates how to send and receive data contained in a user-defined type with the Winsock Control.


MORE INFORMATION
The example uses the Winsock TCP client and server created in the following Microsoft Knowledge Base article:

Q152057 HOWTO: Create & Use a Client/Server Using Winsock TCP Controls

Prior to following this example, make sure you have at least built the framework for the client and server discussed in the aforementioned article. You will be required to make modifications to the DataArrival Event subroutine and the SendData Command subroutine.

Step by Step Example

Enter the following code in the General declarations section of Form1 of both the client and server:

Private Declare Sub CopyMemory Lib "KERNEL32" Alias "RtlMoveMemory" ( hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)

   Private Type MyType
      i As Integer
      l As Long
      s As String * 8
      d As Double
   End Type

Enter the following code for the DataArrival Event subroutine in the Winsock server:

Private Sub TCP1_DataArrival(Index As Integer, ByVal bytesTotal As Long)
         Dim vta
         Dim mt As MyType
         Dim bt() As Byte
         TCP1(Index).GetData vta, vbArray + vbByte, LenB(mt)
         bt = vta
         CopyMemory mt, bt(0),  LenB(mt)
         Debug.Print mt.i; ","; mt.l; ","; mt.s; ","; mt.d
      End Sub

Enter the following code for the SendData Command button in the Winsock client:

   Private Sub cmdSendData_Click()
         Dim mt As MyType
         mt.i = 99
         mt.l = 33
         mt.s = "abcd"
         mt.d = 23.76
         Dim bt() As Byte
         ReDim bt(LenB(mt)) as Byte
         Dim vtdata As Variant
         CopyMemory bt(0), mt, LenB(mt)
         vtdata = bt
         TCP1.SendData vtdata
      End Sub

Courtesy to Microsoft Knowledge Base.

Hope this helps...