Html.DropDownListFor selectedvalue not showing on postback

Question

In my view, there are 5 dropdownlists. The first one is populated when the user first gets to the page. Then the rest of the dropdowns are populated based on what they select from the dropdowns. The binding of the dropdowns work fine..no problem. Basically, there is a submit button on the page which displays the results from the values selected from the dropdowns. The problem is on HttpPost, whatever was selected from the dropdown, they disappear. The other thing is while i keep changing the selectedvalue and do submit, they show up.

For example, i select values from each of the dropdowns. Do a submit, the results display and only the first one shows the selected value. The rest are gone. Then on the same time, I select the remaining values, do a submit, now the first and second show up and the rest are gone. I repeat the same thing, do a postback and the 1st, second and thrid show up and the remaining are gone. Not sure whats happening here. Let me know if I would need to update this post with my code. Just wanted to check if there is quick fix before i post what i did.

    
@using (Html.BeginForm())
{
    
        
            @Html.ActionLink("Back to Reports page", "Index", "Reports/Customers", new { area = "" }, new { @class = "PremireButton" })
        
        
            Customer Survey Report
        
            @if (Model.ShowNational)
            {
                
            }
            @if (Model.ShowArea)
            {
                
            }
            @if (Model.ShowDistrict)
            {
                
            }
            @if (Model.ShowTM)
            {
                
            }
            
                    
                        Select a Country:
                    
                    @Html.DropDownListFor(m => m.NationId, Model.NationalChannelGroups, "Select All")
                    
                

                    
                        Select an Area:
                    
                    @Html.DropDownListFor(m => m.AreaId, Model.AreaChannelGroups, "Select All")
                    
                

                    
                        Select a District:
                    
                    @Html.DropDownListFor(m => m.DistrictId, Model.DistrictChannelGroups, "Select All")
                    
                

                    
                        Select a TM:
                    
                    @Html.DropDownListFor(m => m.TMId, Model.TMChannelGroups, "Select All")
                    
                

                
                    Select a Dealer:
                
                @Html.DropDownListFor(m => m.ChannelId, Model.Channels, "Select All")
                
            
            
                
                    
                
            
        
        @if (Model.ShowCustomerReport)
        {
        if (Model.Report.Count() > 0)
        {
            
                    @{bool alternate = false;}
                    @foreach (var tr in Model.Report)
                    {
                        
                           alternate = !alternate;
                    }
                
                
                    
                        
                            Dealer #
                        
                        
                            District
                        
                        
                            TM
                        
                        
                            Survey Code
                        
                        
                            First Name
                        
                        
                            Last Name
                        
                        
                            Address
                        
                        
                            City
                        
                        
                            State
                        
                        
                            Postal Code
                        
                        
                            Phone
                        
                        
                            Mail Sent
                        
                        
                            Email Sent
                        
                    
                
                
                            
                                @tr.DealerId
                            
                            
                                @tr.District
                            
                            @tr.TM
                            
                            @tr.SurveyCode
                            
                            @tr.FirstName
                            
                            @tr.LastName
                            
                            @tr.Address
                            
                            @tr.City
                            
                            @tr.State
                            
                            @tr.PostalCode
                            
                            @tr.Phone
                            
                            @(tr.MailSent.HasValue ? @tr.MailSent.Value.ToShortDateString() : String.Empty)
                            
                            @(tr.DateCompleted.HasValue ? @tr.DateCompleted.Value.ToShortDateString() : String.Empty)
                            
                        
            
        }
        else
        {
            There are no records to display
        }
       }
    
}

Here is my HttpPost

[HttpPost]
    public ActionResult CustomerReport(AreaManagerModel model)
    { 
         //Display Result here
         LoadDropDowns(model);
         return View("CustomerReport", model);
    }

private void LoadDropDowns(AreaManagerModel model)
    {
        var user = db.Users.Find(SessionHandler.CurrentUser.UserId);
        model.TMChannelGroups = new List();
        model.Channels = new List();
        model.AreaChannelGroups = new List();
        model.NationalChannelGroups = new List();
        model.DistrictChannelGroups = new List();

        var _signedInChannelGroupId = from s in user.ChannelGroups
                                      select s;
        if (_signedInChannelGroupId.Count() > 0)
            model.LoggedChannelGroupId = _signedInChannelGroupId.Select(m => m.ChannelGroupId).First();

        var org = (from o in user.ManagedOrganizations
                   //where o.OrganizationId == 4
                   where o.OrganizationId == 8
                   select o).FirstOrDefault();
        if (org != null || user.IsSuperUser)
        {
            model.ShowNational = true;
            model.ShowArea = true;
            model.ShowDistrict = true;
            model.ShowTM = true;

            model.NationalChannelGroups = from i in db.ChannelGroups
                                          //where i.ChannelGroupTypeId == 4
                                          where i.ChannelGroupTypeId == 6
                                          select new SelectListItem()
                                          {
                                              Text = i.Name,
                                              Value = SqlFunctions.StringConvert((double)i.ChannelGroupId)
                                          };
            if (model.NationId != 0)
            {
                var ngroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                              //where g.ChannelGroupTypeId == 4
                              where g.ChannelGroupTypeId == 6
                              select g).FirstOrDefault();
                if (ngroup != null)
                {
                    model.AreaChannelGroups = from i in ngroup.Children
                                              select new SelectListItem()
                                              {
                                                  Text = i.Name,
                                                  Value = i.ChannelGroupId.ToString()
                                              };
                }
                var agroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                              where g.ChannelGroupTypeId == 1
                              select g).FirstOrDefault();
                if (agroup != null)
                {
                    model.DistrictChannelGroups = from i in agroup.Children
                                                  select new SelectListItem()
                                                  {
                                                      Text = i.Name,
                                                      Value = i.ChannelGroupId.ToString()
                                                  };
                }
                var dgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                              where g.ChannelGroupTypeId == 2
                              select g).FirstOrDefault();
                if (dgroup != null)
                {
                    model.TMChannelGroups = from i in dgroup.Children
                                            select new SelectListItem()
                                            {
                                                Text = i.Name,
                                                Value = i.ChannelGroupId.ToString()
                                            };
                }
                var tgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                              where g.ChannelGroupTypeId == 3
                              select g).FirstOrDefault();
                if (tgroup != null)
                {
                    model.Channels = from i in tgroup.GetAllChannels()
                                     select new SelectListItem()
                                     {
                                         Text = i.ExternalChannelId,
                                         Value = i.ChannelId.ToString()
                                     };
                }
            }
        }
        else
        {
            var ngroup = (from g in user.ChannelGroups
                          //where g.ChannelGroupTypeId == 4
                          where g.ChannelGroupTypeId == 6
                          select g).FirstOrDefault();
            if (ngroup != null)
            {
                model.ShowNational = false;
                model.ShowArea = true;
                model.ShowDistrict = true;
                model.ShowTM = true;

                model.AreaChannelGroups = from i in ngroup.Children
                                          select new SelectListItem()
                                          {
                                              Text = i.Name,
                                              Value = SqlFunctions.StringConvert((double)i.ChannelGroupId)
                                          };
                if (model.AreaId != 0)
                {
                    var agroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                  where g.ChannelGroupTypeId == 1
                                  select g).FirstOrDefault();
                    if (agroup != null)
                    {
                        model.DistrictChannelGroups = from i in agroup.Children
                                                      select new SelectListItem()
                                                      {
                                                          Text = i.Name,
                                                          Value = i.ChannelGroupId.ToString()
                                                      };
                    }
                    var dgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                  where g.ChannelGroupTypeId == 2
                                  select g).FirstOrDefault();
                    if (dgroup != null)
                    {
                        model.TMChannelGroups = from i in dgroup.Children
                                                select new SelectListItem()
                                                {
                                                    Text = i.Name,
                                                    Value = i.ChannelGroupId.ToString()
                                                };
                    }
                    var tgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                  where g.ChannelGroupTypeId == 3
                                  select g).FirstOrDefault();
                    if (tgroup != null)
                    {
                        model.Channels = from i in tgroup.GetAllChannels()
                                         select new SelectListItem()
                                         {
                                             Text = i.ExternalChannelId,
                                             Value = i.ChannelId.ToString()
                                         };
                    }
                }
            }
            else
            {
                var agroup = (from g in user.ChannelGroups
                              where g.ChannelGroupTypeId == 1
                              select g).FirstOrDefault();
                if (agroup != null)
                {
                    model.ShowNational = false;
                    model.ShowArea = false;
                    model.ShowDistrict = true;
                    model.ShowTM = true;
                    model.DistrictChannelGroups = from i in agroup.Children
                                                  select new SelectListItem()
                                                  {
                                                      Text = i.Name,
                                                      Value = i.ChannelGroupId.ToString()
                                                  };
                    if (model.DistrictId != 0)
                    {
                        var dgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                      where g.ChannelGroupTypeId == 2
                                      select g).FirstOrDefault();
                        if (dgroup != null)
                        {
                            model.TMChannelGroups = from i in dgroup.Children
                                                    select new SelectListItem()
                                                    {
                                                        Text = i.Name,
                                                        Value = i.ChannelGroupId.ToString()
                                                    };
                        }
                        var tgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                      where g.ChannelGroupTypeId == 3
                                      select g).FirstOrDefault();
                        if (tgroup != null)
                        {
                            model.Channels = from i in tgroup.GetAllChannels()
                                             select new SelectListItem()
                                             {
                                                 Text = i.ExternalChannelId,
                                                 Value = i.ChannelId.ToString()
                                             };
                        }
                    }
                }
                else
                {
                    var dgroup = (from g in user.ChannelGroups
                                  where g.ChannelGroupTypeId == 2
                                  select g).FirstOrDefault();
                    if (dgroup != null)
                    {
                        model.ShowNational = false;
                        model.ShowArea = false;
                        model.ShowDistrict = false;
                        model.ShowTM = true;
                        model.TMChannelGroups = from i in dgroup.Children
                                                select new SelectListItem()
                                                {
                                                    Text = i.Name,
                                                    Value = i.ChannelGroupId.ToString()
                                                };
                        if (model.TMId != 0)
                        {
                            var tgroup = (from g in SessionHandler.CurrentContext.ChannelGroups
                                            where g.ChannelGroupTypeId == 3
                                            select g).FirstOrDefault();
                        if (tgroup != null)
                        {
                            model.Channels = from i in tgroup.GetAllChannels()
                                             select new SelectListItem()
                                             {
                                                 Text = i.ExternalChannelId,
                                                 Value = i.ChannelId.ToString()
                                             };
                        }
                        }
                    }
                    else
                    {
                        var tgroup = (from g in user.ChannelGroups
                                      where g.ChannelGroupTypeId == 3
                                      select g).FirstOrDefault();
                        if (tgroup != null)
                        {
                            model.ShowNational = false;
                            model.ShowArea = false;
                            model.ShowDistrict = false;
                            model.ShowTM = false;
                            model.Channels = from i in tgroup.GetAllChannels()
                                             select new SelectListItem()
                                             {
                                                 Text = i.ExternalChannelId,
                                                 Value = i.ChannelId.ToString()
                                             };
                        }
                    }
                }
            }
        }
    }

UPDATE:

[HttpPost]
    public ActionResult LoadAreas(int nationId)
    {
        var _Areas = (from c in SessionHandler.CurrentContext.ChannelGroups
                      join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
                      where cgt.Name == "Area" && c.ParentChannelGroupId == nationId
                      select new AreaName() { Id = c.ChannelGroupId, Name = c.Name }).OrderBy(m => m.Name);

        if (_Areas == null)
            return Json(null);
        List managers = (List)_Areas.ToList();

        return Json(managers);
    }
    [HttpPost]
    public ActionResult LoadDistricts(int areaId)
    {
        var _Districts = (from c in SessionHandler.CurrentContext.ChannelGroups
                    join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
                    where cgt.Name == "District" && c.ParentChannelGroupId == areaId
                    select new DistrictName() { Id = c.ChannelGroupId, Name = c.Name }).OrderBy(m => m.Name);

        if (_Districts == null)
            return Json(null);

        List managers = (List)_Districts.ToList();
        return Json(managers);
    }
    [HttpPost]
    public ActionResult LoadTerritoryManagers(int districtId)
    {
        var _TMS = (from c in SessionHandler.CurrentContext.ChannelGroups
                    join cgt in SessionHandler.CurrentContext.ChannelGroupTypes on c.ChannelGroupTypeId equals cgt.ChannelGroupTypeId
                    where cgt.Name == "Territory" && c.ParentChannelGroupId == districtId
                    select new TMManager() { Id = c.ChannelGroupId, Name = c.Name }).OrderBy(m => m.Name);

        if (_TMS == null)
            return Json(null);

        List managers = (List)_TMS.ToList();
        return Json(managers);
    }
    [HttpPost]
    public ActionResult LoadDealers(int tmId)
    {
        var _dealers = (from c in SessionHandler.CurrentContext.Channels
                    where c.ChannelGroupId == tmId
                    select new SurveyDealer() { Id = c.ChannelId, DealerId = c.ExternalChannelId }).OrderBy(m => m.DealerId);

        if (_dealers == null)
            return Json(null);

        List dealers = (List)_dealers.ToList();
        return Json(dealers);
    }

Ben Finkel · Accepted Answer

Let's see your View code to start with, that should help.

UPDATE:

Your render code:

DropDownListFor(m => m.TMId, Model.TMChannelGroups, "Select All")

Is forcing the DropDownBox to select the value "Select All" regardless of what the value of TMId is.

Get rid of that last paremeter entirely and instead change your server-side code to return a SelectList object with 0/Select All as the first SelectListItem. Then, your model object will properly choose the correct option from the DropDownList.

Html.DropDownListFor selectedvalue not showing on postback

Answers (1)

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