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SendCFindRequest Method

Summary
Sends a C-FIND-REQ message to a peer member of a connection.
Syntax
C#
C++
public void SendCFindRequest( 
   byte presentationID, 
   int messageID, 
   string affectedClass, 
   DicomCommandPriorityType priority, 
   DicomDataSet dataSet 
) 
public: 
void SendCFindRequest(  
   byte presentationID, 
   int messageID, 
   String^ affectedClass, 
   DicomCommandPriorityType priority, 
   DicomDataSet^ dataSet 
)  

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.

affectedClass
The class affected by the request. This will be a SOP Class or a Meta SOP Class.

priority
The priority level of the message. The Service Class Provider may or may not support priority. Therefore, setting this parameter may or may not have any effect.

dataSet
A DicomDataSet object that contains the Data Set to be found.

Remarks

Calling this method generates a call to OnReceiveCFindRequest on the SCP. The SCP should respond by calling SendCFindResponse which will generate a call to OnReceiveCFindResponse. You must create a Data Set and insert elements corresponding to the data you wish to find. This Data Set is then passed to the method.

Example

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

C#
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 OnReceiveReleaseResponse() 
   { 
      waitEvent.Set(); 
   } 
 
   protected override void OnReceiveCFindResponse(byte presentationID, 
                                                   int messageID, 
                                                   string affectedClass, 
                                                   DicomCommandStatusType status, 
                                                   DicomDataSet dataSet) 
   { 
      Debug.Assert(status == DicomCommandStatusType.Success, "Status should be success"); 
      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 OnReceiveReleaseRequest() 
   { 
      SendReleaseResponse(); 
   } 
 
   protected override void OnReceiveCFindRequest(byte presentationID, int messageID, string affectedClass, DicomCommandPriorityType priority, DicomDataSet dataSet) 
   { 
      DicomElement element; 
 
      Debug.Assert(dataSet != null, "Dataset should not be null"); 
      Debug.Assert(priority == DicomCommandPriorityType.Medium, "Priority should be medium"); 
 
      // 
      // Check dataset 
      // 
      element = dataSet.FindFirstElement(null, DicomTag.QueryRetrieveLevel, true); 
      Debug.Assert(element != null, "Element (QueryRetrieveLevel) should not be null"); 
      Debug.Assert(dataSet.GetStringValue(element, 0) == "PATIENT", "QueryRetrieveLevel should be PATIENT"); 
 
      element = dataSet.FindFirstElement(null, DicomTag.PatientName, true); 
      Debug.Assert(element != null, "Element (PatientName) should not be null"); 
      Debug.Assert(dataSet.GetStringValue(element, 0) == "TEST", "PatientName should be TEST"); 
 
      element = dataSet.FindFirstElement(null, DicomTag.PatientID, true); 
      Debug.Assert(element != null, "Element (PatientID) should not be null"); 
      Debug.Assert(dataSet.GetStringValue(element, 0) == "ID", "PatientID should be ID"); 
 
      // 
      // Normally you would create a dataset that patches the query. 
      //  we will send back the same dataset here.. 
      // 
      SendCFindResponse(presentationID, messageID, affectedClass, DicomCommandStatusType.Success, dataSet); 
   } 
} 
 
class Server : DicomNet 
{ 
   ServerConnection client; 
 
   public Server() 
       : base(null, DicomNetSecurityMode.None) 
   { 
   } 
 
   protected override void OnAccept(DicomExceptionCode error) 
   { 
      client = new ServerConnection(); 
 
      Accept(client); 
   } 
} 
 
 
public void SendCFindRequestSample() 
{ 
   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); 
         associate.AddPresentationContext(3, 0, DicomUidType.PatientRootQueryFind); 
         associate.AddTransfer(3, DicomUidType.ImplicitVRLittleEndian); 
         client.SendAssociateRequest(associate); 
         if (!client.Wait()) // wait for connection to finish 
         { 
            Debug.Fail("SendAssociateRequest timed out"); 
         } 
 
         byte pid = client.Association.FindAbstract(DicomUidType.PatientRootQueryFind); 
         DicomDataSet ds = new DicomDataSet(); 
         DicomElement element; 
 
         // 
         // Set up the find parameters 
         // 
         ds.Initialize(DicomClassType.PatientRootQueryPatient, DicomDataSetInitializeType.ExplicitVRLittleEndian); 
         element = ds.FindFirstElement(null, DicomTag.QueryRetrieveLevel, true); 
         if (element == null) 
         { 
            element = ds.InsertElement(null, false, DicomTag.QueryRetrieveLevel, DicomVRType.UN, false, 0); 
         } 
         ds.SetStringValue(element, "PATIENT", DicomCharacterSetType.Default); 
 
         element = ds.FindFirstElement(null, DicomTag.PatientName, true); 
         if (element == null) 
         { 
            element = ds.InsertElement(null, false, DicomTag.PatientName, DicomVRType.UN, false, 0); 
         } 
         ds.SetStringValue(element, "TEST", DicomCharacterSetType.Default); 
 
         element = ds.FindFirstElement(null, DicomTag.PatientID, true); 
         if (element == null) 
         { 
            element = ds.InsertElement(null, false, DicomTag.PatientID, DicomVRType.UN, false, 0); 
         } 
         ds.SetStringValue(element, "ID", DicomCharacterSetType.Default); 
 
         client.SendCFindRequest(pid, 2, DicomUidType.PatientRootQueryFind, DicomCommandPriorityType.Medium, ds); 
         if (!client.Wait()) // wait for CFind to finish 
         { 
            Debug.Fail("SendCFindRequest timed out"); 
         } 
 
         client.CloseForced(true); 
      } 
      server.CloseForced(true); 
   } 
 
   DicomEngine.Shutdown(); 
   DicomNet.Shutdown(); 
} 
Requirements

Target Platforms

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