Filter data using a drop down RSS

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  CarCancelo

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  Filter data using a drop down

  Jan 25, 2019 02:01 AM|CarCancelo|LINK

  Hello peeeps

  I have two tables with a many-to-many relationship. I want to filter the result set from table 1 table with the assigned entities of table 2. I can't seem to get the filter to work properly. Any help would be most appreciated.

  Code below:

  CONTROLLER:

  == CONTROLLER ==

          [HttpPost]

  <div>        public ActionResult Index(string filterMarkets)</div> <div>        {</div> <div>            var asrs = from a in db.ASR</div> <div>                       select a;</div> <div> </div> <div>            var markets = from m in db.Market</div> <div>                          select m;</div> <div> </div> <div>            ViewBag.assignedMarkets = new SelectList(db.Market, "MarketID", "MarketName");</div> <div> </div> <div>            if (!String.IsNullOrEmpty(filterMarkets))</div> <div>            {</div> <div>                asrs = asrs.Where(a => a.FullName.Contains(filterMarkets.ToString()));</div> <div>            }</div> <div>            else if (!String.IsNullOrEmpty(filterMarkets))</div> <div>            {</div> <div>                markets = markets.Where(m => m.MarketName.ToUpper().Contains(filterMarkets.ToUpper()));</div> <div> </div> <div>            }</div> <div>            return View(asrs.ToList());</div> <div>        }</div> <div>==========</div>

  == VIEW ==

  <div>                @using (Html.BeginForm())</div> <div>                {</div> <div>                    @Html.AntiForgeryToken()</div> <div>                    @Html.DropDownList("assignedMarkets", ViewBag.MarketsList as SelectList, "-- Filter By Market --", new { @onchange = "this.form.submit();", @class = "btn btn-primary dropdown-toggle btn-sm", @value = "filterMarkets" })</div> <div>                }</div>

  ========

• • Reply
  mgebhard

  All-Star

  52201 Points

  23274 Posts

  Re: Filter data using a drop down

  Jan 25, 2019 02:46 PM|mgebhard|LINK

  ViewBag.MarketsList is not assigned a value in the code snippet.  Please review and run your code through the Visual Studio debugger as the code has several logic errors.

  https://docs.microsoft.com/en-us/visualstudio/debugger/navigating-through-code-with-the-debugger?view=vs-2017

  public ActionResult Index(string filterMarkets)
  {
  	var asrs = from a in db.ASR
  	select a;
  	var markets = from m in db.Market
  	select m;
  	ViewBag.assignedMarkets = new SelectList(db.Market, "MarketID", "MarketName");
  	if (!String.IsNullOrEmpty(filterMarkets))
  	{
  		asrs = asrs.Where(a => a.FullName.Contains(filterMarkets.ToString()));
  	}
  	else if (!String.IsNullOrEmpty(filterMarkets))
  	{
  		markets = markets.Where(m => m.MarketName.ToUpper().Contains(filterMarkets.ToUpper()));
  	}
  	return View(asrs.ToList());
  }
  ==========
  == VIEW ==
  @using (Html.BeginForm())
  {
  	@Html.AntiForgeryToken()
  	@Html.DropDownList("assignedMarkets", ViewBag.MarketsList as SelectList, "-- Filter By Market --", new { @onchange = "this.form.submit();", @class = "btn btn-primary dropdown-toggle btn-sm", @value = "filterMarkets" })
  }

• • Reply
  jzero

  Participant

  1051 Points

  658 Posts

  Re: Filter data using a drop down

  Jan 25, 2019 02:48 PM|jzero|LINK

  Is your return correct? It always return asrs

  public ActionResult Index(string filterMarkets) {
    var asrs = from a in db.ASR select a;
    var markets = from m in db.Market select m;
    ViewBag.assignedMarkets = new SelectList(db.Market, "MarketID", "MarketName");
    if (!String.IsNullOrEmpty(filterMarkets)) {
      asrs = asrs.Where(a => a.FullName.Contains(filterMarkets.ToString()));
    }
    else if (!String.IsNullOrEmpty(filterMarkets))
    {
    markets = markets.Where(m => m.MarketName.ToUpper().Contains(filterMarkets.ToUpper()));
    }
    return View(asrs.ToList());
  }

• • Reply
  CarCancelo

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  0 Points

  26 Posts

  Re: Filter data using a drop down

  Jan 25, 2019 07:21 PM|CarCancelo|LINK

  It should return the asrs. However, the filter should return the filtered asrs results. If you think it should return something other than that, let me know. I am also going to look at the previous response, it mentioned logic errors, I'll see what that's about.

• • Reply
  Yuki Tao

  Contributor

  3710 Points

  1431 Posts

  Re: Filter data using a drop down

  Jan 28, 2019 09:35 AM|Yuki Tao|LINK

  Hi CarCancelo,

  CarCancelo

  I want to filter the result set from table 1 table with the assigned entities of table 2. I can't seem to get the filter to work properly.

  if (!String.IsNullOrEmpty(filterMarkets))
  	{
  		asrs = asrs.Where(a => a.FullName.Contains(filterMarkets.ToString())); //line1
  	}
  	else if (!String.IsNullOrEmpty(filterMarkets))
  	{
  		markets = markets.Where(m => m.MarketName.ToUpper().Contains(filterMarkets.ToUpper())); //line2
  	}
  	return View(asrs.ToList());

  According to your code,this does have a logic error.

  Both line1 and line2 will run,but you only return asrs so that it makes line2 invalid.

  I know you would like to make line1 and line2 contact and filter the data between them.

  And there may be duplicate data.

  So,Since I do not know what is your source,I suggest you could combine use .Intersect(), . Except(),.Add(),.Distinct()...

  They will help you handle data.

  Best Regards.

  Yuki Tao

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