Virtual Channels with C#

I would appreciate any assistance you can offer.

To the quick here is my issue:

I am getting a System.AccessViolationException when attempting to read

the channel on the server side.

I am using:

//All C# 2005

//I believe i have to call VirtualChannelOpen() again eventhough I have

a pointer

//eitherway I get the same exception

IntPtr intHandle = RDPManager.WTSVirtualChannelOpen(IntPtr.Zero, -1,

"Impact")

RDPManager.WTSVirtualChannelRead(intHandle, intTimeOut, bytes,

bytes.Length, ref written)

//The API Call looks like

[DllImport("Wtsapi32.dll", SetLastError = true)]

public static extern bool WTSVirtualChannelRead(IntPtr hChannelHandle,

ulong timeout, byte[] Buffer, int Length, ref int pBytesWritten)

Here is how I got there:

Currently I am working with documentation found:

http://www.microsoft.com/technet/archive/termsrv/maintain/featusability/tsrvapi.mspx?mfr=true

http://msdn2.microsoft.com/en-us/library/aa383580.aspx

http://msdn2.microsoft.com/en-us/library/aa383853.aspx

http://www.codeproject.com/cs/system/TSAddinInCS.asp?df=100&forumid=358838&exp=0&select=1961960

That is all I can really find about the topic.

I am still having problems with WTSVirtualChannelRead, at least I think I

am. Nothing seems to be writtin.

Here is a brief overview of What I have done:

I created a messagelib that will contain messages I am sending back and

forth.

Class MessageHeader

int MessageType

MessageBase Message

Abstract Class MessageBase

Class StatusMessage: MessageBase

String StatusText

Now on my session component I do:

1. Call WTSVirtualChannelOpen to get a handle on the channel

2. Create a StatusMessage

StatusText = "ACK"

3. Serialize the message

4. Send the message

Now on my client component I do:

1. VirtualChannelEntry waits to be called (This is what loads the

assembly), store the handle in mHandle point my VirtualChannelInit to the

function VirtualChannelInitEventProc

2. Once the VirtualChannelInitEventProc determines that a complete

message was send over, I deserialize and process the message

3. Determine the type of message that was send (type == 1

//StatusMessage)

4. Determine what the StatusText is "ACK"

5. Generate a reply StatusMessage "NACK"

6. Serialize the message

7. Send the message

a. open the channel using the WTSVirtualChannelOpen(mHandle,-1,

"Impact"), store the new pointer in intTemp

b. write the data using WTSVirtualChannelWrite at this point, I

believe my data is waiting for the server to pick it up. I get a true

returned from WTSVirtualChannelWrite

Back to the session component

I have a background worker process that is monitoring for pending

messages.

1. Open the channel with WTSVirtualChannelOpen

2. Read until there is nothing left to read, add the read bytes into

list<byte> using WTSVirtualChannelRead

3. If anything was read

a. Deserialize the MessageHeader

b. Determine Message Type (type == 1//StatusMessage)

c. Report StatusText "NACK"

//At this point, nothing is read by the WTSVirtualChannelRead. I don't

know where my message is.

I am getting a System.AccessViolationException when attempting to read

the channel.

I am using:

//I believe i have to call VirtualChannelOpen() again eventhough I have

a pointer

//eitherway I get the same exception

IntPtr intHandle = RDPManager.VirtualChannelOpen(IntPtr.Zero, -1,

"Impact")

RDPManager.VirtualChannelRead(intHandle, intTimeOut, bytes,

bytes.Length, ref written)

//The API Call looks like

[DllImport("Wtsapi32.dll", SetLastError = true)]

public static extern bool WTSVirtualChannelRead(IntPtr hChannelHandle,

ulong timeout, byte[] Buffer, int Length, ref int pBytesWritten)

Does anyone have any ideas of where to start?

BTW, I am using C# 2005. But the concept should be the same.

Server: Win2K3 server with Terminal Services Installed

Client: WinXP workstation with platform SDK installed

Thanks in advance.