SendCCancelRequest Method

Summary

Sends a C-CANCEL-REQ message to a peer member of a connection.

Syntax

C++

public void SendCCancelRequest( 
   byte presentationID, 
   int messageID 
)

Public Sub SendCCancelRequest( _ 
   ByVal presentationID As Byte, _ 
   ByVal messageID As Integer _ 
)

public: 
void SendCCancelRequest(  
   byte presentationID, 
   int messageID 
)

Parameters

presentationID
The Presentation Context ID. The ID provides information about both the class type of the data and the Transfer Syntax to use when transferring the data.

messageID
The Message ID. Each message sent by a member of a connection should have a unique ID. Since a member of a connection may send several messages, this ID allows that member to identify when a specific request has been completed.

Remarks

Calling this method generates a call to OnReceiveCCancelRequest on the SCP.

Example

This is a comprehensive sample that shows how to process a DICOM C-Cancel operation on both the SCP (server) and the SCU (client) sides.

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 OnClose(DicomExceptionCode error, DicomNet net) 
   { 
      waitEvent.Set(); 
   } 
} 
 
class ServerConnection : DicomNet 
{ 
   public ServerConnection() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   protected override void OnReceiveAssociateRequest(DicomAssociate association) 
   { 
      DicomAssociate retAssociation = new DicomAssociate(false); 
 
      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); 
         } 
 
         retAssociation.AddTransfer(id, trSyntax); 
      } 
      SendAssociateAccept(retAssociation); 
   } 
 
   protected override void OnReceiveCCancelRequest(byte presentationID, int messageID) 
   { 
      Debug.Assert(presentationID == 1, "Presentation ID should be 1"); 
      Debug.Assert(messageID == 1, "Message ID should be 1"); 
      Close(); 
   } 
} 
 
class Server : DicomNet 
{ 
   ServerConnection client; 
 
   public Server() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   protected override void OnAccept(DicomExceptionCode error) 
   { 
      client = new ServerConnection(); 
 
      Accept(client); 
   } 
} 
 
public void SendCCancleRequestSample() 
{ 
   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; 
         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"); 
         } 
 
         IntPtr p = new IntPtr(5); 
         client.SendCCancelRequest(1, 1); 
         if (!client.Wait()) // wait for SendNonSecureISCL to finish 
         { 
            Debug.Fail("SendCCancelRequest timed out"); 
         } 
         if (client.IsConnected()) 
            client.CloseForced(true); 
      } 
      server.CloseForced(true); 
   } 
 
   DicomEngine.Shutdown(); 
   DicomNet.Shutdown(); 
}

Imports Leadtools 
Imports Leadtools.Dicom 
 
<StructLayout(LayoutKind.Sequential)> 
Public Structure MSG 
   Public hwnd As IntPtr 
   Public message As UInteger 
   Public wParam As IntPtr 
   Public lParam As IntPtr 
   Public time As UInteger 
   Public p As System.Drawing.Point 
End Structure 
 
Public Enum WaitReturn 
   Complete 
   Timeout 
End Enum 
 
Private Class Utils 
   <DllImport("user32.dll")> 
   Shared Function PeekMessage(<System.Runtime.InteropServices.Out()> ByRef lpMsg As MSG, ByVal hWnd As IntPtr, ByVal wMsgFilterMin As UInteger, 
                                  ByVal wMsgFilterMax As UInteger, ByVal wRemoveMsg As UInteger) As <MarshalAs(UnmanagedType.Bool)> Boolean 
   End Function 
 
   <DllImport("user32.dll")> 
   Shared Function TranslateMessage(ByRef lpMsg As MSG) As Boolean 
   End Function 
   <DllImport("user32.dll")> 
   Shared Function DispatchMessage(ByRef lpmsg As MSG) As IntPtr 
   End Function 
 
   Private Const PM_REMOVE As UInteger = 1 
 
   Public Shared Function WaitForComplete(ByVal mill As Double, ByVal wh As WaitHandle) As WaitReturn 
      Dim goal As TimeSpan = New TimeSpan(DateTime.Now.AddMilliseconds(mill).Ticks) 
 
      Do 
         Dim msg As MSG = New MSG() 
 
         If PeekMessage(msg, IntPtr.Zero, 0, 0, PM_REMOVE) Then 
            TranslateMessage(msg) 
            DispatchMessage(msg) 
         End If 
 
         If wh.WaitOne(New TimeSpan(0, 0, 0), False) Then 
            Return WaitReturn.Complete 
         End If 
 
         If goal.CompareTo(New TimeSpan(DateTime.Now.Ticks)) < 0 Then 
            Return WaitReturn.Timeout 
         End If 
 
      Loop While True 
   End Function 
End Class 
 
Private Class Client : Inherits DicomNet 
   Private _LastError As DicomExceptionCode = DicomExceptionCode.Success 
   Private waitEvent As AutoResetEvent = New AutoResetEvent(False) 
 
   Public Sub New() 
      MyBase.New(Nothing, DicomNetSecurityMode.None) 
   End Sub 
 
   Public ReadOnly Property LastError() As DicomExceptionCode 
      Get 
         Return _LastError 
      End Get 
   End Property 
 
   Public Function Wait() As Boolean 
      Dim ret As WaitReturn 
 
      _LastError = DicomExceptionCode.Success 
      ret = Utils.WaitForComplete((5 * 60) * 1000, waitEvent) 
 
      Return (ret = WaitReturn.Complete) 
   End Function 
 
   Protected Overrides Sub OnConnect(ByVal [error] As DicomExceptionCode) 
      _LastError = [error] 
      waitEvent.Set() 
   End Sub 
 
   Protected Overrides Sub OnReceiveAssociateAccept(ByVal association As DicomAssociate) 
      waitEvent.Set() 
   End Sub 
 
   Protected Overrides Sub OnClose(ByVal [error] As DicomExceptionCode, ByVal net As DicomNet) 
      waitEvent.Set() 
   End Sub 
End Class 
 
Private Class ServerConnection : Inherits DicomNet 
   Public Sub New() 
      MyBase.New(Nothing, DicomNetSecurityMode.None) 
   End Sub 
 
   Protected Overrides Sub OnReceiveAssociateRequest(ByVal association As DicomAssociate) 
      Dim retAssociation As DicomAssociate = New DicomAssociate(False) 
 
      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 = &H100000, "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 
      Dim x As Integer = 0 
      Do While x < association.PresentationContextCount 
         Dim id As Byte = association.GetPresentationContextID(x) 
         Dim abSyntax As String = association.GetAbstract(id) 
         Dim trSyntax As String = DicomUidType.ImplicitVRLittleEndian 
 
         retAssociation.AddPresentationContext(id, 0, abSyntax) 
         If association.GetTransferCount(id) > 0 Then 
            trSyntax = association.GetTransfer(id, 0) 
         End If 
 
         retAssociation.AddTransfer(id, trSyntax) 
         x += 1 
      Loop 
      SendAssociateAccept(retAssociation) 
   End Sub 
 
   Protected Overrides Sub OnReceiveCCancelRequest(ByVal presentationID As Byte, ByVal messageID As Integer) 
      Debug.Assert(presentationID = 1, "Presentation ID should be 1") 
      Debug.Assert(messageID = 1, "Message ID should be 1") 
      Close() 
   End Sub 
End Class 
 
Private Class Server : Inherits DicomNet 
   Private client As ServerConnection 
 
   Public Sub New() 
      MyBase.New(Nothing, DicomNetSecurityMode.None) 
   End Sub 
 
   Protected Overrides Sub OnAccept(ByVal [error] As DicomExceptionCode) 
      client = New ServerConnection() 
 
      Accept(client) 
   End Sub 
End Class 
 
 
Public Sub SendCCancleRequestSample() 
   DicomEngine.Startup() 
   DicomNet.Startup() 
 
   Using server As Server = New Server() 
      Using client As Client = New Client() 
         ' 
         ' Connect to server 
         ' 
         server.Listen("127.0.0.1", 104, 1) ' start server 
         client.Connect(Nothing, 1000, "127.0.0.1", 104) ' connect to server 
         If (Not client.Wait()) Then ' wait for connection to finish 
            Debug.Fail("Connection timed out") 
         End If 
         Debug.Assert(client.LastError = DicomExceptionCode.Success, "Connection failed") 
         Debug.Assert(client.IsConnected(), "Client not connected") 
 
         ' 
         ' Send associate request 
         ' 
         Dim associate As DicomAssociate = New DicomAssociate(True) 
 
         associate.Called = "ServerTest" 
         associate.Calling = "ClientTest" 
         associate.ImplementClass = "1.2.840.114257.1" 
         associate.ImplementationVersionName = "1" 
         associate.MaxLength = &H100000 
         associate.AddPresentationContext(1, 0, DicomUidType.VerificationClass) 
         associate.AddTransfer(1, DicomUidType.ImplicitVRLittleEndian) 
         client.SendAssociateRequest(associate) 
         If (Not client.Wait()) Then ' wait for connection to finish 
            Debug.Fail("SendAssociateRequest timed out") 
         End If 
 
         Dim p As IntPtr = New IntPtr(5) 
         client.SendCCancelRequest(1, 1) 
         If (Not client.Wait()) Then ' wait for SendNonSecureISCL to finish 
            Debug.Fail("SendCCancelRequest timed out") 
         End If 
         If client.IsConnected() Then 
            client.CloseForced(True) 
         End If 
      End Using 
      server.CloseForced(True) 
   End Using 
 
   DicomEngine.Shutdown() 
   DicomNet.Shutdown() 
End Sub

Requirements

Target Platforms

Reference

DicomNet Class

DicomNet Members

OnReceiveCCancelRequest Method

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Help Version 20.0.2020.3.31

Leadtools.Dicom Assembly

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Leadtools.Dicom Namespace

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