Variable in Switch-Case in Razor? RSS

• • Reply
  jj819

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  65 Points

  250 Posts

  Variable in Switch-Case in Razor?

  Sep 21, 2018 02:24 PM|jj819|LINK

  Hi, I have A-Z switch case loop. Just wondering if the following code can be simplified? Got error message that case has to be a constant.

  @for (char c = 'A'; c < 'Z'; c++)
      {
  		@Html.Raw("<tr><td class=first-child>")@c @Html.Raw("</td>")
  				 
          switch (c)
          {		 
                case 'A':
                    
                         @Html.Raw("<td> <a name='A'></a><ul>")
                          foreach (var exp in A)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							 break;
  							 @Html.Raw("</ul></td>")
  			case 'B':
                    
                         @Html.Raw("<td> <a name='B'></a><ul>")
                          foreach (var exp in B)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							 break;
  							 @Html.Raw("</ul></td>")
  			case 'C':
                    
                         @Html.Raw("<td> <a name='C'></a><ul>")
                          foreach (var exp in C)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							 break;
  							 @Html.Raw("</ul></td>")		
  			case 'D':
                    
                         @Html.Raw("<td> <a name='D'></a><ul>")
                          foreach (var exp in D)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							 break;
  							 @Html.Raw("</ul></td>")
  ...
  }
   @Html.Raw("</tr>")
  }

• • Reply
  mgebhard

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  23259 Posts

  Re: Variable in Switch-Case in Razor?

  Sep 21, 2018 02:32 PM|mgebhard|LINK

  You've over complicated the design and do not need a switch at all just a loop since you know the char value.

• • Reply
  ryanbesko

  Contributor

  7048 Points

  2187 Posts

  Re: Variable in Switch-Case in Razor?

  Sep 21, 2018 02:32 PM|ryanbesko|LINK

  One issue I see is that these lines:

  @Html.Raw("</ul></td>")

  will never get hit because they're after the break statement.  You should see a warning about "Unreachable code detected".

  Mark all posts that give the desired result the answer. If you only mark the last that gave you clarification because you misread an earlier post others will be confused. Some of us are here to help others and our point to post ratio matters.
• • Reply
  jj819

  Member

  65 Points

  250 Posts

  Re: Variable in Switch-Case in Razor?

  Sep 21, 2018 03:03 PM|jj819|LINK

  Here my A, B , C.. is also a list of string. I couldn't use char variable c cast to string list c.

  <table class="ExpertiseTable">
      <tr>
          
              @for (char c = 'A'; c < 'Z'; c++)
              {
  									 <th>
                  <a href="#@c">@c</a>
  				</th>
              }
        
          
      </tr>
      @{
          List<string> A = new List<string>();
          List<string> B = new List<string>();
          List<string> C = new List<string>();
          List<string> D = new List<string>();
          List<string> E = new List<string>();
          List<string> F = new List<string>();
          List<string> G = new List<string>();
          List<string> H = new List<string>();
          List<string> I = new List<string>();
          List<string> J = new List<string>();
          List<string> K = new List<string>();
          List<string> L = new List<string>();
          List<string> M = new List<string>();
          List<string> N = new List<string>();
          List<string> O = new List<string>();
          List<string> P = new List<string>();
          List<string> Q = new List<string>();
          List<string> R = new List<string>();
          List<string> S = new List<string>();
          List<string> T = new List<string>();
          List<string> U = new List<string>();
          List<string> V = new List<string>();
          List<string> W = new List<string>();
          List<string> X = new List<string>();
          List<string> Y = new List<string>();
          List<string> Z = new List<string>();
          Dictionary<char, List<string>> names = new Dictionary<char, List<string>>();
      }
  
  
      @foreach (var item in ViewBag.Expertises)
      {
          switch (char.ToUpper(item[0]))
          {
              case 'A':
                  A.Add(item);
                  break;
              case 'B':
                  B.Add(item);
                  break;
              case 'C':
                  C.Add(item);
                  break;
              case 'D':
                  D.Add(item);
                  break;
              case 'E':
                  E.Add(item);
                  break;
              case 'F':
                  F.Add(item);
                  break;
              case 'G':
                  G.Add(item);
                  break;
              case 'H':
                  H.Add(item);
                  break;
              case 'I':
                  I.Add(item);
                  break;
              case 'J':
                  J.Add(item);
                  break;
              case 'K':
                  K.Add(item);
                  break;
              case 'L':
                  L.Add(item);
                  break;
              case 'S':
                  S.Add(item);
                  break;
              case 'T':
                  T.Add(item);
                  break;
              case 'P':
                  P.Add(item);
                  break;
  
          }
         
  
  
      }
  @for (char c = 'A'; c < 'Z'; c++)
      {
  		switch (c)
          {		 
                case 'A':
                    
                         @Html.Raw("<td> <a name='A'></a><ul>")
                          foreach (var exp in A)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							@Html.Raw("</ul></td>")
  							 break;
  							 
  			case 'B':
                    
                         @Html.Raw("<td> <a name='B'></a><ul>")
                          foreach (var exp in B)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							 @Html.Raw("</ul></td>")
  							 break;
  							
  			case 'C':
                    
                         @Html.Raw("<td> <a name='C'></a><ul>")
                          foreach (var exp in C)
                          {
                             @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { Keywords = @exp }) @Html.Raw("</li>")
                          }
  							  @Html.Raw("</ul></td>")
  							 break;		
  ...
  }
          
  		 @Html.Raw("</tr>")
      }
  </table>

• • Reply
  mgebhard

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  23259 Posts

  Re: Variable in Switch-Case in Razor?

  Sep 21, 2018 03:48 PM|mgebhard|LINK

  IMHO, still overly complicated.  Sort the results in the controller action not the View.   As far as I can tell there is no reason for the switch as a simple loop will do fine as long as you format the View Model in the controller first.

• • Reply
  Nan Yu

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  Re: Variable in Switch-Case in Razor?

  Sep 24, 2018 02:19 AM|Nan Yu|LINK

  Hi jj819,

  The question you meet may be how to find the list by local variables :

    foreach (var exp in A)

  You can use a data structure that's designed for it - in this case, a Dictionary<string, List<string>>. This will allow you to set a name as a key to access an object:

  List<string> A = new List<string>();
  List<string> B = new List<string>();
  List<string> C = new List<string>();
  List<string> D = new List<string>();
  List<string> E = new List<string>();
  List<string> F = new List<string>();
  
  
  Dictionary<string, List<string>> lists = new Dictionary<string, List<string>>();
  lists.Add("A", A);
  lists.Add("B", B);
  lists.Add("C", C);
  lists.Add("D", D);
  
  ........
  

  Then you can access a specific list by name through the Dictionary's indexer property:

  var cList = lists["A"];

  Then your loop will like something as :

  @for ()
  {
      .....
      var cList = lists[c.ToString()];
      foreach (var exp in cList )
      {
          @Html.Raw("<li>") @Html.ActionLink(@exp, "SearchResults", new { 
                Keywords = @exp }) @Html.Raw("</li>")
      }
  
  
      .....
  }

  But i would suggest re-design your logic , put the complicated logic on server side .

  Best Regards,

  Nan Yu