How can I add an item to a SelectList in ASP net MVC

Question

Basically I am looking to insert an item at the beginning of a SelectList with the default value of 0 and the Text Value of   -- Select One --   Something like  SelectList list   new SelectList repository func ToList     ListItem li   new ListItem value  value   list items add li     Can this be done

User · Answer

Okay I like clean code so I made this an extension method

static public class SelectListHelper
{
    static public SelectList Add(this SelectList list, string text, string value = "", ListPosition listPosition = ListPosition.First)
    {
        if (string.IsNullOrEmpty(value))
        {
            value = text;
        }
        var listItems = list.ToList();
        var lp = (int)listPosition;
        switch (lp)
        {
            case -1:
                lp = list.Count();
                break;
            case -2:
                lp = list.Count() / 2;
                break;
            case -3:
                var random = new Random();
                lp = random.Next(0, list.Count());
                break;
        }
        listItems.Insert(lp, new SelectListItem { Value = value, Text = text });
        list = new SelectList(listItems, "Value", "Text");
        return list;
    }

    public enum ListPosition
    {
        First = 0,
        Last = -1,
        Middle = -2,
        Random = -3
    }
}

Usage (by example):

var model = new VmRoutePicker
    {
     Routes =
     new SelectList(_dataSource.Routes.Select(r => r.RouteID).Distinct())
     };                                     
  model.Routes = model.Routes.Add("All", "All", SelectListHelper.ListPosition.Random);
//or
  model.Routes = model.Routes.Add("All");

User · Answer

May not sound very elegant  but I usually do something like this       var items   repository func ToList        items Insert 0  new funcItem   ID   0  TextValue     None           ViewBag MyData   new SelectList items

User · Answer

Here html helper for you  public static SelectList IndividualNamesOrAll this SelectList Object        MedicalVarianceViewsDataContext LinqCtx   new MedicalVarianceViewsDataContext           not correct need individual view      var IndividualsListBoxRaw      from x in LinqCtx ViewIndividualsNames                                   orderby x FullName                                  select x        List lt SelectListItem gt  items   new SelectList                                  IndividualsListBoxRaw                                  First Hospital Case Nbr                                   FullName                                   ToList         items Insert 0   new SelectListItem   Text    All Individuals                                            Value    0 0                                            Selected   true           Object   new SelectList  items  Value   Text         return Object

User · Answer

The  ToList   Insert     method puts an element into your List  Any position can be specified  After ToList just add  Insert 0   quot - - First Item - - quot   Your code SelectList list   new SelectList repository func ToList      New Code SelectList list   new SelectList repository func ToList   Insert 0   quot - - First Item - - quot

User · Answer

I got this to work by Populating a SelectListItem  converting to an List  and adding a value at index 0     List lt SelectListItem gt  items   new SelectList CurrentViewSetups   SetupId    SetupName   setupid  ToList     items Insert 0   new SelectListItem   Text     None    Value    0       ViewData  SetupsSelectList     items

User · Answer

A work-around is to use  tvanfosson s answer  the selected answer  and use JQuery  or Javascript  to set the option s value to 0     document  ready function                  DropDownListId option first   val  0              Hope this helps

User · Answer

There really isn t a need to do this unless you insist on the value of 0   The HtmlHelper DropDownList extension allows you to set an option label that shows up as the initial value in the select with a null value   Simply use one of the DropDownList signatures that has the option label    lt    Html DropDownList   DropDownValue                           IEnumerable lt SelectListItem gt  ViewData  Menu                             -- Select One --      gt

User · Answer

This is possible     Create the select list item you want to add SelectListItem selListItem   new SelectListItem     Value    null   Text    Select One        Create a list of select list items - this will be returned as your select list List lt SelectListItem gt  newList   new List lt SelectListItem gt        Add select list item to list of selectlistitems newList Add selListItem      Return the list of selectlistitems as a selectlist return new SelectList newList   Value    Text   null

User · Answer

As this option may need in many different manners  i reached to conclusion to develop an object so that it can be used in different scenarios and in future projects  first add this class to your project  public class SelectListDefaults       private IList lt SelectListItem gt  getDefaultItems   new List lt SelectListItem gt          public SelectListDefaults                 this AddDefaultItem   All     -1              public SelectListDefaults string text  string value                this AddDefaultItem text  value             public IList lt SelectListItem gt  GetDefaultItems               get                                       return getDefaultItems                       public void AddDefaultItem string text  string value                        getDefaultItems Add new SelectListItem     Text   text  Value   value                                   Now in Controller Action you can do like this         Now you can do like this     ViewBag MainCategories   new SelectListDefaults   GetDefaultItems Concat new SelectList db MainCategories   MainCategoryID    Name   Request  DropDownListMainCategory       -1            Or can change it by such a simple way     ViewBag MainCategories   new SelectListDefaults  Any   0   GetDefaultItems Concat new SelectList db MainCategories   MainCategoryID    Name   Request  DropDownListMainCategory       0            And even can add more options     SelectListDefaults listDefaults   new SelectListDefaults        listDefaults AddDefaultItme   Top 5     -5           If Top 5 selected by user  you may need to do something here with db MainCategories  or pass in parameter to method      ViewBag MainCategories   listDefaults GetDefaultItems Concat new SelectList db MainCategories   MainCategoryID    Name   Request  DropDownListMainCategory       -1       And finally in View you will code like this    Html DropDownList  DropDownListMainCategory    IEnumerable lt SelectListItem gt  ViewBag MainCategories  new    class    form-control   onchange    this form submit

User · Answer

private SelectList AddFirstItem SelectList list                        List lt SelectListItem gt   list   list ToList                 list Insert 0  new SelectListItem     Value    -1   Text    This Is First Item                  return new SelectList  IEnumerable lt SelectListItem gt   list   Value    Text                This Should do what you need  just send your selectlist and it will return a select list with an item in index 0  You can custome the text value or even the index of the item you need to insert

User · Answer

I liked  AshOoO s answer but like  Rajan Rawal I needed to preserve selected item state  if any   So I added my customization to his method AddFirstItem    public static SelectList AddFirstItem SelectList origList  SelectListItem firstItem        List lt SelectListItem gt  newList   origList ToList        newList Insert 0  firstItem        var selectedItem   newList FirstOrDefault item   gt  item Selected       var selectedItemValue   String Empty      if  selectedItem    null                selectedItemValue   selectedItem Value             return new SelectList newList   Value    Text   selectedItemValue

User · Answer

I don t if anybody else has a better option      lt   if  Model VariableName          Model VariableName   null      gt      lt    html DropDpwnList  ListName     SelectList  ViewData  viewName                 new stlye        gt   lt     else    gt   lt    html DropDpwnList  ListName     SelectList  ViewData  viewName             Model VariableName  new stlye        gt   lt     gt

User · Answer

Try something like the following code    MyDAO MyDAO   new MyDAO        List lt MyViewModel gt   MyDefault   new List lt MyViewModel gt                      new MyViewModel                      Prop1   All                       Prop2    Select all                                               ViewBag MyViewBag                   new SelectList MyDAO                  MyList   Union                       MyDefault                         Prop1    Prop2

[asp.net-mvc] How can I add an item to a SelectList in ASP.net MVC

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