mcs/class/System.Web/System.Web.UI.WebControls/DropDownList.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
   2 // a copy of this software and associated documentation files (the
   3 // "Software"), to deal in the Software without restriction, including
   4 // without limitation the rights to use, copy, modify, merge, publish,
   5 // distribute, sublicense, and/or sell copies of the Software, and to
   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2005-2010 Novell, Inc. (http://www.novell.com)
  21 //
  22 // Authors:
  23 //      Peter Bartok    (pbartok@novell.com)
  24 //
  25 //
  26
  27 using System.Collections.Specialized;
  28 using System.ComponentModel;
  29 using System.Drawing;
  30 using System.Security.Permissions;
  31
  32 namespace System.Web.UI.WebControls
  33 {
  34         // CAS
  35         [AspNetHostingPermissionAttribute (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  36         [AspNetHostingPermissionAttribute (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  37         // attributes
  38         [ValidationProperty("SelectedItem")]
  39         [SupportsEventValidation]
  40         public class DropDownList : ListControl, IPostBackDataHandler
  41         {
  42                 #region Public Constructors
  43                 public DropDownList() {
  44                 }
  45                 #endregion      // Public Constructors
  46
  47                 #region Public Instance Properties
  48                 [Browsable(false)]
  49                 public override Color BorderColor {
  50                         get { return base.BorderColor; }
  51                         set { base.BorderColor = value; }
  52                 }
  53
  54                 [Browsable(false)]
  55                 public override BorderStyle BorderStyle {
  56                         get { return base.BorderStyle; }
  57                         set { base.BorderStyle = value; }
  58                 }
  59
  60                 [Browsable(false)]
  61                 public override Unit BorderWidth {
  62                         get { return base.BorderWidth; }
  63                         set { base.BorderWidth = value; }
  64                 }
  65
  66                 [DefaultValue(0)]
  67                 [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  68                 [WebSysDescription ("")]
  69                 [WebCategory ("Misc")]
  70                 public override int SelectedIndex {
  71                         get {
  72                                 int selected;
  73
  74                                 selected = base.SelectedIndex;
  75                                 if ((selected != -1) || (Items.Count == 0))
  76                                         return selected;
  77
  78                                 Items[0].Selected = true;
  79                                 return 0;
  80                         }
  81
  82                         set { base.SelectedIndex = value; }
  83                 }
  84                 public override bool SupportsDisabledAttribute {
  85                         get { return RenderingCompatibilityLessThan40; }
  86                 }
  87                 #endregion      // Public Instance Properties
  88
  89                 #region Protected Instance Methods
  90                 protected override void AddAttributesToRender(HtmlTextWriter writer)
  91                 {
  92                         Page page = Page;
  93                         if (page != null)
  94                                 page.VerifyRenderingInServerForm (this);
  95
  96                         if (writer == null)
  97                                 return;
  98                         if (!String.IsNullOrEmpty (UniqueID))
  99                                 writer.AddAttribute (HtmlTextWriterAttribute.Name, this.UniqueID, true);
 100
 101                         if (!IsEnabled && SelectedIndex == -1)
 102                                 SelectedIndex = 1;
 103
 104                         if (AutoPostBack) {
 105                                 string onchange = page != null ? page.ClientScript.GetPostBackEventReference (GetPostBackOptions (), true) : String.Empty;
 106                                 onchange = String.Concat ("setTimeout('", onchange.Replace ("\\", "\\\\").Replace ("'", "\\'"), "', 0)");
 107                                 writer.AddAttribute (HtmlTextWriterAttribute.Onchange, BuildScriptAttribute ("onchange", onchange));
 108                         }
 109
 110                         base.AddAttributesToRender(writer);
 111                 }
 112
 113                 PostBackOptions GetPostBackOptions ()
 114                 {
 115                         PostBackOptions options = new PostBackOptions (this);
 116                         options.ActionUrl = null;
 117                         options.ValidationGroup = null;
 118                         options.Argument = String.Empty;
 119                         options.RequiresJavaScriptProtocol = false;
 120                         options.ClientSubmit = true;
 121
 122                         Page page = Page;
 123                         options.PerformValidation = CausesValidation && page != null && page.AreValidatorsUplevel (ValidationGroup);
 124                         if (options.PerformValidation)
 125                                 options.ValidationGroup = ValidationGroup;
 126
 127                         return options;
 128                 }
 129
 130                 protected override ControlCollection CreateControlCollection ()
 131                 {
 132                         return base.CreateControlCollection();
 133                 }
 134
 135                 protected internal override void VerifyMultiSelect ()
 136                 {
 137                         throw new HttpException ("DropDownList only may have a single selected item");
 138                 }
 139                 #endregion      // Protected Instance Methods
 140
 141                 #region Interface Methods
 142                 protected virtual bool LoadPostData (string postDataKey, NameValueCollection postCollection)
 143                 {
 144                         EnsureDataBound ();
 145                         int index = Items.IndexOf(postCollection[postDataKey]);
 146                         ValidateEvent (postDataKey, postCollection [postDataKey]);
 147                         if (index != this.SelectedIndex) {
 148                                 SelectedIndex = index;
 149                                 return true;
 150                         }
 151
 152                         return false;
 153                 }
 154
 155                 protected virtual void RaisePostDataChangedEvent ()
 156                 {
 157                         if (CausesValidation) {
 158                                 Page page = Page;
 159                                 if (page != null)
 160                                         page.Validate (ValidationGroup);
 161                         }
 162
 163                         OnSelectedIndexChanged(EventArgs.Empty);
 164                 }
 165
 166                 bool IPostBackDataHandler.LoadPostData (string postDataKey, NameValueCollection postCollection)
 167                 {
 168                         return LoadPostData (postDataKey, postCollection);
 169                 }
 170
 171                 void IPostBackDataHandler.RaisePostDataChangedEvent ()
 172                 {
 173                         RaisePostDataChangedEvent ();
 174                 }
 175                 #endregion      // Interface Methods
 176         }
 177 }