Virtual Channels with C#

[Guest amdrit]

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.