Error-There is already an open DataReader associated with this Command which must be closed first. RSS

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  JagjitSingh

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  Error-There is already an open DataReader associated with this Command which must be closed first...

  Apr 14, 2017 03:06 PM|JagjitSingh|LINK

  Hi

   Below is the code

  function FillCity() {
          var stateId = $('#StateId').val();
          $.ajax({
              url: '/Customer/GetCity',
              type: "GET",
              dataType: "JSON",
              data: { StateId: stateId },
              success: function (cities) {
                  $("#CityId").html(""); // clear before appending new list 
                  $.each(cities, function (i, city) {
                      $("#CityId").append(
                          $('<option></option>').val(city.CityId).html(city.CityName));
                  });
              },
              error: function (xhr, ajaxOptions, thrownError) {
                  $("#errorModalBody").html('Status : ' + xhr.status + ' Error : ' + thrownError);
                  $("#errorModal").modal('show');
              }
          });
      }
  
  Controller
  public ActionResult GetCity(int StateId)
          {
              var cities = db.Cities.Where(c => c.StateId == StateId);
              return Json(cities, JsonRequestBehavior.AllowGet);
          }

  Thanks

• • Reply
  deepalgorith...

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  Re: Error-There is already an open DataReader associated with this Command which must be closed f...

  Apr 14, 2017 03:55 PM|deepalgorithm|LINK

  This error can show up if you execute a query while iterating over the results from another query, but from your example its not clear if this is the actual issue.

  Allowing MARS in your connection string may solve the issue. Add 

  MultipleActiveResultSets=true

   to the provider part of your connection string.

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• • Reply
  JagjitSingh

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  Re: Error-There is already an open DataReader associated with this Command which must be closed f...

  Apr 14, 2017 04:12 PM|JagjitSingh|LINK

  Hi

    I am getting server error 500

• • Reply
  deepalgorith...

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  Re: Error-There is already an open DataReader associated with this Command which must be closed f...

  Apr 14, 2017 04:17 PM|deepalgorithm|LINK

  Thats an internal server error. Where is the error happening? What line of code specifically?

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  Cathy Zou

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  Re: Error-There is already an open DataReader associated with this Command which must be closed f...

  Apr 17, 2017 02:11 AM|Cathy Zou|LINK

  Hi JagjitSingh,

  Two commonly used methods for a request-response between a client and server are: GET and POST.

  • GET - Requests data from a specified resource
  • POST - Submits data to be processed to a specified resource

  GET is basically used for just getting (retrieving) some data from the server. Note: The GET method may return cached data.

  POST can also be used to get some data from the server. However, the POST method NEVER caches data, and is often used to send data along with the request.

  https://www.w3schools.com/jquery/jquery_ajax_get_post.asp

  For your 500 error:  you  could change your request type to Post and ensure that the Controller Action is decorated with the [HttpPost]

  attribute, indicating it should be used for POST calls :

  Besides, you could  read the  correct reply in the following link to check your code:

  http://stackoverflow.com/questions/36894273/jquery-ajax-call-to-pass-json-array-in-mvc-500-internal-server-error

  Best regards

  Cathy

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