OnAccept Method

Summary

Notifies a listening connection (SCP) that it can accept pending connection requests.

Syntax

Objective-C

C++/CLI

protected virtual void OnAccept( 
   DicomExceptionCode error 
)

- (void)onAccept:(LTDicomErrorCode)error;

protected: 
virtual void OnAccept(  
   DicomExceptionCode error 
)

Parameters

error
An error code.

Remarks

A call to this method is generated on an SCP when an SCU calls Connect. To accept a connection request, call Accept.

You should always accept a connection request. Once the connection is made you can check the client and close the connection if you do not wish to maintain it. Since the connection requests are queued, if you do not accept a connection, it remains in the queue. When the next request is received, it is placed in the queue behind the first request. Calling Accept at this point will connect the first request, not the second, since the first request is still in the queue.

Example

using Leadtools; 
using Leadtools.Dicom; 
 
 
[StructLayout(LayoutKind.Sequential)] 
public struct MSG 
{ 
   public IntPtr hwnd; 
   public uint message; 
   public IntPtr wParam; 
   public IntPtr lParam; 
   public uint time; 
   public System.Drawing.Point p; 
} 
 
public enum WaitReturn 
{ 
   Complete, 
   Timeout, 
} 
 
class Utils 
{ 
   [DllImport("user32.dll")] 
   [return: MarshalAs(UnmanagedType.Bool)] 
   static extern bool PeekMessage(out MSG lpMsg, IntPtr hWnd, 
                                  uint wMsgFilterMin, uint wMsgFilterMax, 
                                  uint wRemoveMsg); 
 
   [DllImport("user32.dll")] 
   static extern bool TranslateMessage([In] ref MSG lpMsg); 
   [DllImport("user32.dll")] 
   static extern IntPtr DispatchMessage([In] ref MSG lpmsg); 
 
   const uint PM_REMOVE = 1; 
 
   public static WaitReturn WaitForComplete(double mill, WaitHandle wh) 
   { 
      TimeSpan goal = new TimeSpan(DateTime.Now.AddMilliseconds(mill).Ticks); 
 
      do 
      { 
         MSG msg = new MSG(); 
 
         if (PeekMessage(out msg, IntPtr.Zero, 0, 0, PM_REMOVE)) 
         { 
            TranslateMessage(ref msg); 
            DispatchMessage(ref msg); 
         } 
 
         if (wh.WaitOne(new TimeSpan(0, 0, 0), false)) 
         { 
            return WaitReturn.Complete; 
         } 
 
         if (goal.CompareTo(new TimeSpan(DateTime.Now.Ticks)) < 0) 
         { 
            return WaitReturn.Timeout; 
         } 
 
      } while (true); 
   } 
} 
 
class Client : DicomNet 
{ 
   DicomExceptionCode _LastError = DicomExceptionCode.Success; 
   AutoResetEvent waitEvent = new AutoResetEvent(false); 
 
   public Client() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   public DicomExceptionCode LastError 
   { 
      get 
      { 
         return _LastError; 
      } 
   } 
 
   public bool Wait() 
   { 
      WaitReturn ret; 
 
      _LastError = DicomExceptionCode.Success; 
      ret = Utils.WaitForComplete((5 * 60) * 1000, waitEvent); 
 
      return (ret == WaitReturn.Complete); 
   } 
 
   protected override void OnConnect(DicomExceptionCode error) 
   { 
      _LastError = error; 
      waitEvent.Set(); 
   } 
 
   protected override void OnReceiveAssociateAccept(DicomAssociate association) 
   { 
      waitEvent.Set(); 
   } 
 
   protected override void OnReceiveAssociateReject(DicomAssociateRejectResultType result, 
                                                    DicomAssociateRejectSourceType source, 
                                                    DicomAssociateRejectReasonType reason) 
   { 
      Debug.Assert(result == DicomAssociateRejectResultType.Permanent, "Result should be: " + DicomAssociateRejectResultType.Permanent.ToString()); 
      Debug.Assert(source == DicomAssociateRejectSourceType.User, "Source should be: " + DicomAssociateRejectSourceType.User.ToString()); 
      Debug.Assert(reason == DicomAssociateRejectReasonType.Limit, " Reason should be: " + DicomAssociateRejectReasonType.Limit.ToString()); 
      waitEvent.Set(); 
   } 
 
   protected override void OnReceiveReleaseResponse() 
   { 
      waitEvent.Set(); 
   } 
} 
 
class ServerConnection : DicomNet 
{ 
   public bool Fail = false; 
 
   public ServerConnection() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   protected override void OnReceiveAssociateRequest(DicomAssociate association) 
   { 
      DicomAssociate retAssociation = new DicomAssociate(false); 
 
      if (Fail) 
      { 
         SendAssociateReject(DicomAssociateRejectResultType.Permanent, 
                             DicomAssociateRejectSourceType.User, 
                             DicomAssociateRejectReasonType.Limit); 
         return; 
      } 
 
      Debug.Assert(association.Called == "ServerTest", "Called AETitle should be ServerTest"); 
      Debug.Assert(association.Calling == "ClientTest", "Calling AETitle should be ClientTest"); 
      Debug.Assert(association.ImplementClass == "1.2.840.114257.1", "Implementation class should be 1.2.840.114257.1"); 
      Debug.Assert(association.ImplementationVersionName == "1", "Implementation version should be 1"); 
      Debug.Assert(association.MaxLength == 0x100000, "Max length should be 0x100000"); 
      Debug.Assert(association.GetAbstract(1) == DicomUidType.VerificationClass, "Presentation index 1 should be " + DicomUidType.VerificationClass); 
      Debug.Assert(association.GetTransfer(1, 0) == DicomUidType.ImplicitVRLittleEndian, "Abstract Syntax (1,0) should be " + DicomUidType.ImplicitVRLittleEndian); 
 
      // 
      // Build our Association Accept 
      // 
      retAssociation.Called = association.Called; 
      retAssociation.Calling = association.Calling; 
      retAssociation.ImplementClass = association.ImplementClass; 
      retAssociation.ImplementationVersionName = association.ImplementationVersionName; 
      for (int x = 0; x < association.PresentationContextCount; x++) 
      { 
         byte id = association.GetPresentationContextID(x); 
         string abSyntax = association.GetAbstract(id); 
         string trSyntax = DicomUidType.ImplicitVRLittleEndian; 
 
         retAssociation.AddPresentationContext(id, 0, abSyntax); 
         if (association.GetTransferCount(id) > 0) 
         { 
            trSyntax = association.GetTransfer(id, 0); 
         } 
         //Over here we can call retAssociation.SetAbstract to update the abstract 
         //syntax for any of the sresentation contexts 
         retAssociation.AddTransfer(id, trSyntax); 
         if (retAssociation.GetTransferCount(id) == 0) 
         { 
            // 
            // Presentation id doesn't have any abstract 
            //  syntaxes therefore we will reject it. 
            // 
            retAssociation.SetResult(id, DicomAssociateAcceptResultType.AbstractSyntax); 
            Debug.Assert(retAssociation.GetResult(id) == DicomAssociateAcceptResultType.AbstractSyntax, "Result should be: " + DicomAssociateAcceptResultType.AbstractSyntax.ToString()); 
         } 
 
 
         //  We can also call in here SetPresentationContextID if we would like  
         //  to change some of the presentation IDs 
         //  And SetTransfer to update the Transfer Syntax for a certian 
         //  presentation context. 
 
      } 
      SendAssociateAccept(retAssociation); 
   } 
 
   protected override void OnReceiveReleaseRequest() 
   { 
      SendReleaseResponse(); 
   } 
}; 
 
class Server : DicomNet 
{ 
   ServerConnection client; 
 
   public Server() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   public bool Fail 
   { 
      get 
      { 
         if (client == null) 
            return false; 
 
         return client.Fail; 
      } 
 
      set 
      { 
         if (client != null) 
         { 
            client.Fail = value; 
         } 
      } 
   } 
 
   protected override void OnAccept(DicomExceptionCode error) 
   { 
      client = new ServerConnection(); 
 
      Accept(client); 
   } 
} 
 
public void SendAssociateRequestSample() 
{ 
   DicomEngine.Startup(); 
   DicomNet.Startup(); 
 
   using (Server server = new Server()) 
   { 
      using (Client client = new Client()) 
      { 
         // 
         // Connect to server 
         // 
         server.Listen("127.0.0.1", 104, 1); // start server 
         client.Connect(null, 1000, "127.0.0.1", 104); // connect to server 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("Connection timed out"); 
         } 
         Debug.Assert(client.LastError == DicomExceptionCode.Success, "Connection failed"); 
         Debug.Assert(client.IsConnected(), "Client not connected"); 
 
         // 
         // Send associate request 
         // 
         DicomAssociate associate = new DicomAssociate(true); 
 
         associate.Called = "ServerTest"; 
         associate.Calling = "ClientTest"; 
         associate.ImplementClass = "1.2.840.114257.1"; 
         associate.ImplementationVersionName = "1"; 
         associate.MaxLength = 0x100000; 
         //We can also call in here associate.Default() to initialize  
         //the association with default values. 
         associate.AddPresentationContext(1, 0, DicomUidType.VerificationClass); 
         associate.AddTransfer(1, DicomUidType.ImplicitVRLittleEndian); 
         client.SendAssociateRequest(associate); 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("SendAssociateRequest timed out"); 
         } 
 
         // 
         // SendReleaseRequest 
         // 
         client.SendReleaseRequest(); 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("SendAssociateRequest timed out"); 
         } 
 
         // 
         // Force association to send SendAssociateReject. This is for 
         // testing purposes only.  Only one association should be sent 
         // per connection. 
         // 
         server.Fail = true; 
         client.SendAssociateRequest(associate); 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("SendAssociateRequest timed out"); 
         } 
         server.Fail = false; 
 
         // 
         // SendReleaseRequest 
         // 
         client.SendReleaseRequest(); 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("SendAssociateRequest timed out"); 
         } 
 
         client.CloseForced(true); 
      } 
      server.CloseForced(true); 
   } 
 
   DicomEngine.Shutdown(); 
   DicomNet.Shutdown(); 
}

Requirements

Target Platforms

Reference

DicomNet Class

DicomNet Members

Connect(String,Int32,String,Int32) Method

Accept Method

OnConnect Method

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Help Version 23.0.2024.8.20

Leadtools.Dicom Assembly

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