“The underlying connection was closed: The connection was closed unexpectedly.” While returning Data Table from WCF service.

37 Comments

• After struggling with the same issue you are having, I sent a request to Microsoft and I got a simple answer that I did not expect, and the solution works perfectly.
  Simply give your Table a name. If you don’t, which is what I was doing, it will block teh client and time ou.
  e.g. DataTable dt = new DataTable(“name”)
  or DataTable dt = new DataTable();
  dt.TableName = “name”;
  then hydrate your DataTable any way you want (from the database or from another data source), and return from WCF method withouy any problems.
  I’d be interested if it works out for you.
  -Youssef

  • Thank you . .works like magic ^_^

    • Thanks Trex! Happy Coding! 🙂

  • it works thanks

    • thanks boss

  • Thanks a lot

  • Youssef: you are the man!

    Your post saved me a lot of time.

    thank you!

• it worked ina charm !!! thanks

• Tried this…but didn’t work out !

  Hence had to revert to returning DataSet itself instead of DataTable
  🙁

  Regards,
  Kris

• that’s a wonderful solution. thanks

• Awesome

• Thanks buddy, it saved a lot of time for me I was stuck for a long time on this error.
  Thanks,
  Abdul Rafay
  Abdul Rafays BizTalk Blog

• At last after 5 hours today and 5 yesterday i have found a solution. My issue was cuased by cloning a typed table to a datatable – using a dataset to conviently populate a types datatable and then clone it to an datatable for consuming by remote app – without any refs to the typed dataset etc…. so here is how it works….

  public System.Data.DataTable GetData(string Product, int ID)
  {
  dsSettingsAndResultsTableAdapters.MT2_settings_resultsTableAdapter dta = new micro_trends.co.uk.WCF.Service.StrategySettings.dsSettingsAndResultsTableAdapters.MT2_settings_resultsTableAdapter();
  dsSettingsAndResults.MT2_settings_resultsDataTable tdt = null;
  tdt = dta.GetDataByID(ID);
  DataTable dt = new DataTable(tdt.TableName);
  dt.Merge(tdt.Clone(), false, MissingSchemaAction.Add);
  return dt;
  }

  goddam messy… much easier to use a normal datatable and populate via a dal / dataadapter and stored proc etc….
  but i was in a rush….

• Solution that works for dataset or dataTable

  System.Data.DataSet IUpdates.GetDataSet()
  {
  DataSet ds = new DataSet(“MTProducts”);
  ds.Merge(mTProductsDataset);
  return ds;
  }

  System.Data.DataTable IUpdates.GetDataTable()
  {
  DataTable dt = new DataTable(“Products”);
  dt.Merge(mTProductsDataset.Products);
  return dt;
  }

• test client

  [ServiceContract]
  public interface IUpdates
  {

  [OperationContract]
  DataSet GetDataSet();

  [OperationContract]
  DataTable GetDataTable();

  }

  static void Main(string[] args)
  {

  try
  {
  // Create a channel
  EndpointAddress address = new EndpointAddress(Settings.SercviceAddress);
  BasicHttpBinding binding = new BasicHttpBinding();
  using (ChannelFactory factory = new ChannelFactory(binding, address))
  {
  IUpdates channel = factory.CreateChannel();
  Console.WriteLine(“Fetch dataTable”);
  System.Data.DataTable dt = channel.GetDataTable();
  if (dt != null)
  {
  Console.WriteLine(“Fetch Success”);
  dt.WriteXml(@”dt.xml”);
  Console.WriteLine(File.ReadAllText(@”dt.xml”));
  }
  else
  {
  Console.WriteLine(“Fetch Error”);
  }

  Console.WriteLine(“Fetch dataSet”);
  System.Data.DataSet ds = channel.GetDataSet();
  if (ds != null)
  {
  Console.WriteLine(“Fetch Success”);
  ds.WriteXml(@”ds.xml”);
  Console.WriteLine(File.ReadAllText(@”ds.xml”));
  }
  else
  {
  Console.WriteLine(“Fetch Error”);
  }

  ((IChannel)channel).Close();

  }

  }
  catch (Exception ex)
  {
  Console.WriteLine(ex.ToString());
  //
  }
  Console.Read();
  }

• Thanks It helps me a lot i worked on this one week

• […] The busiest day of the year was November 23rd with 246 views. The most popular post that day was “The underlying connection was closed: The connection was closed unexpectedly.” While re…. […]

• Hi Kiran

  I have my WCF returning a list of objects and the last link in webliography helped me in this case.

  http://blogs.conchango.com/merrickchaffer/archive/2007/09/19/WCF-System.Net.WebException_3A00_-The-underlying-connection-was-closed_3A00_-The-connection-was-closed-unexpectedly.aspx

  Thanks much
  Jyotsna

• Thanks Youssef, naming the table fixed the problem. Now if only I could have found this thread before I gave myself a concussion from banging my head on the table.

• Thank you, this was driving me nuts and changing to a dataset finally got it working. Awesome!

• A big Thank you! Mine was returning a Hastable (which WCF isn’t fond of it seems). Changed it and it worked again!

• yes its working for me. thanks a lot for the post.

• Thanks !

  It really worked for me

• Thanks a lot, it saved a lot of time for me I was stuck for a long time on this error.
  Thanks,

• WCF..
  public DataTable newfuncion()
  {
  int qtype = 1;
  SqlCommand cmd = new SqlCommand(“StateBind”, con);
  cmd.CommandType = CommandType.StoredProcedure;
  cmd.Parameters.Add(“@Qtype”, SqlDbType.Int).Value = qtype;
  SqlDataAdapter adap = new SqlDataAdapter(cmd);
  DataTable dt = new DataTable(“Product”);
  adap.Fill(dt);
  return dt;
  }

  Client..
  dt = client.newfuncion();

  I am getting error like ”
  Unable to Automatically debug .. urlservice
  the remote procedure could not be debugged .this usuallly indicates that debugging has mnot enabled on the server.”

  I am not using any break point .

• thanks it worked

• This is Just awesome man. I am pulling out my head to figure it out what happens, but you just give a simple solution of all

• thank you so much ….what a idea

• Thanks a lot.. for Dataset It is working fine but in List it shows same error

  • Sj Alex — Glad to know that you found it useful!

    Thanks for your comment — It stimulates!

    Keep sharing, Keep visiting and Keep reading! 🙂

    Sincerely,
    Kiran Patil

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• thanks a lot..
  i was stuck in that problem from last few days..and finally i solved it by your blog..thank u so much

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• thanks alot.. i ws juggling alot to get the solution..
  it worked like magic…

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