C DropDownList with a Dictionary as DataSource

Question

I want to set DataTextField and DataValueField of a Dropdownlist  languageList  using a Dictionary  list  of languageCod  en-gb  as key and language name  english  as the text to display   Relevant Code   string   languageCodsList  service LanguagesAvailable    Dictionary lt string  string gt  list                       new Dictionary lt string  string gt  languageCodsList Length    foreach  string cod in languageCodsList        CultureInfo cul   new CultureInfo cod       list Add cod  cul DisplayName     languageList DataSource   list  languageList DataBind      How can I set DataTextField and DataValueField

User · Accepted Answer

Like that you can set DataTextField and DataValueField of DropDownList using  Key  and  Value  texts         Dictionary lt string  string gt  list   new Dictionary lt string  string gt         list Add  item 1    Item 1        list Add  item 2    Item 2        list Add  item 3    Item 3        list Add  item 4    Item 4         ddl DataSource   list      ddl DataTextField    Value       ddl DataValueField    Key       ddl DataBind

User · Answer

When a dictionary is enumerated  it will yield KeyValuePair lt TKey TValue gt  objects    so you just need to specify  Value  and  Key  for DataTextField and DataValueField respectively  to select the Value Key properties   Thanks to Joe s comment  I reread the question to get these the right way round  Normally I d expect the  key  in the dictionary to be the text that s displayed  and the  value  to be the value fetched  Your sample code uses them the other way round though  Unless you really need them to be this way  you might want to consider writing your code as   list Add cul DisplayName  cod      And then changing the binding to use  Key  for DataTextField and  Value  for DataValueField  of course    In fact  I d suggest that as it seems you really do want a list rather than a dictionary  you might want to reconsider using a dictionary in the first place  You could just use a List lt KeyValuePair lt string  string gt  gt    string   languageCodsList   service LanguagesAvailable    var list   new List lt KeyValuePair lt string  string gt  gt      foreach  string cod in languageCodsList        CultureInfo cul   new CultureInfo cod       list Add new KeyValuePair lt string  string gt  cul DisplayName  cod        Alternatively  use a list of plain CultureInfo values  LINQ makes this really easy   var cultures   service LanguagesAvailable                          Select language   gt  new CultureInfo language    languageList DataTextField    DisplayName   languageList DataValueField    Name   languageList DataSource   cultures  languageList DataBind      If you re not using LINQ  you can still use a normal foreach loop   List lt CultureInfo gt  cultures   new List lt CultureInfo gt     foreach  string cod in service LanguagesAvailable          cultures Add new CultureInfo cod      languageList DataTextField    DisplayName   languageList DataValueField    Name   languageList DataSource   cultures  languageList DataBind

User · Answer

If the DropDownList is declared in your aspx page and not in the codebehind  you can do it like this    aspx    lt asp DropDownList ID  ddlStatus  runat  server  DataSource   lt    Statuses   gt        DataValueField  Key  DataTextField  Value  gt  lt  asp DropDownList gt     aspx cs   protected void Page Load object sender  EventArgs e        ddlStatus DataBind           or use Page DataBind   to bind everything    public Dictionary lt int  string gt  Statuses       get                   do database webservice lookup here to populate Dictionary

User · Answer

Just use  Key  and  Value

[c#] C# DropDownList with a Dictionary as DataSource

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