DropDownList not working RSS

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  humble-appre...

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  DropDownList not working

  May 06, 2012 04:53 PM|LINK

  Hello!

  I’m trying to populate a dropdownlist with a list of value that sometimes may come in with a selected value. My problem is that it gives me this error:

  The ViewData item that has the key 'ModuleID' is of type 'System.Guid' but must be of type 'IEnumerable<SelectListItem>'.

  This is my view:

  <div class="editor-label">

              @Html.LabelFor(model => model.ModuleID, "Module")

          </div>

          <div class="editor-field">

              @Html.DropDownList("ModuleID", "Please select")

              @Html.ValidationMessageFor(model => model.ModuleID)

          </div>

   

  This is my Controller with the Action and method to populate the list:

  void PopulateModuleList(Guid selectedModule)

          {

              List<Module> modules = SecurityModuleViewModelBuilder.ConvertToModules(repository.GetModules(true));

   

              Module module = modules.Find(m => m.ID == selectedModule);

   

              ViewBag.ModuleID = new SelectList(modules, "ID", "Name", module);

          }

   

          public ActionResult CreateTask(Guid? id)

          {

              Task task = new Task();

             

              if (id.HasValue && id.Value != Guid.Empty)

                  PopulateModuleList(id.Value);

   

              return View(task);

          }

  The behaviour I’m looking for is that when an GUID is past that value comes in as selected on the view and when it is not, display “Please select”.

  Thanks!

  Thanks,
  
  humble-apprentice
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  ignatandrei

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  Re: DropDownList not working

  May 06, 2012 05:15 PM|LINK

  humble-apprentice

  The ViewData item that has the key 'ModuleID' is of type 'System.Guid' but must be of type 'IEnumerable<SelectListItem>'.

  Where do you populate with System.Guid ? please show all code!

  My .NET blog : http://msprogrammer.serviciipeweb.ro/ |2012 Programmer tools
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  humble-appre...

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  32 Points

  73 Posts

  Re: DropDownList not working

  May 07, 2012 12:15 PM|LINK

  ModuleID is a property of Task of type Guid.

  This is how I solved the issue:

  void PopulateModuleList(Guid selectedModule)
          {
              List<Module> modules = SecurityModuleViewModelBuilder.ConvertToModules(repository.GetModules(true));
  
              if (selectedModule != Guid.Empty)
                  ViewBag.ModuleID = new SelectList(modules, "ID", "Name", selectedModule);
              else
                  ViewBag.ModuleID = new SelectList(modules, "ID", "Name");
          }
  
          public ActionResult CreateTask(Guid? id)
          {
              Task task = new Task();
  
              if (id.HasValue && id.Value != Guid.Empty)
                  PopulateModuleList(id.Value);
              else
                  PopulateModuleList(Guid.Empty);
  
              return View(task);
          }

  This code populates the dropdown, if an ID is passed it is set as selected and if not it just displays the list.

  Thanks,
  
  humble-apprentice
  • Marked as answer by humble-apprentice on May 07, 2012 12:16 PM