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

   1 //
   2 // System.Web.UI.WebControls.ListBox.cs
   3 //
   4 // Authors:
   5 //   Gaurav Vaish (gvaish@iitk.ac.in)
   6 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   7 //
   8 // (C) Gaurav Vaish (2002)
   9 // (C) 2003 Andreas Nahr
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.Drawing;
  35 using System.Collections;
  36 using System.Collections.Specialized;
  37 using System.ComponentModel;
  38 using System.Globalization;
  39 using System.Web;
  40 using System.Web.UI;
  41
  42 namespace System.Web.UI.WebControls
  43 {
  44         [ValidationProperty("SelectedItem")]
  45         public class ListBox : ListControl, IPostBackDataHandler
  46         {
  47                 public ListBox () : base ()
  48                 {
  49                 }
  50
  51                 [Browsable (false)]
  52                 public override Color BorderColor
  53                 {
  54                         get { return base.BorderColor; }
  55                         set { base.BorderColor = value; }
  56                 }
  57
  58                 [Browsable (false)]
  59                 public override BorderStyle BorderStyle
  60                 {
  61                         get { return base.BorderStyle; }
  62                         set { base.BorderStyle = value; }
  63                 }
  64
  65                 [Browsable (false)]
  66                 public override Unit BorderWidth
  67                 {
  68                         get { return base.BorderWidth; }
  69                         set { base.BorderWidth = value; }
  70                 }
  71
  72
  73                 [DefaultValue (4), Bindable (true), WebCategory ("Appearance")]
  74                 [WebSysDescription ("The number of rows displayed by the control.")]
  75                 public virtual int Rows
  76                 {
  77                         get {
  78                                 object o = ViewState ["Rows"];
  79                                 return (o == null) ? 4 : (int) o;
  80                         }
  81
  82                         set {
  83                                 if (value < 1 || value > 2000)
  84                                         throw new ArgumentOutOfRangeException ("value", "Rows value has to be >= 0 and <= 2000.");
  85
  86                                 ViewState ["Rows"] = value;
  87                         }
  88                 }
  89
  90                 [DefaultValue (typeof (ListSelectionMode), "Single"), WebCategory ("Behavior")]
  91                 [WebSysDescription ("The mode describing how the entries can be selected.")]
  92                 public virtual ListSelectionMode SelectionMode
  93                 {
  94                         get
  95                         {
  96                                 object o = ViewState ["SelectionMode"];
  97                                 return (o == null) ? ListSelectionMode.Single : (ListSelectionMode) o;
  98                         }
  99                         set
 100                         {
 101                                 if (!Enum.IsDefined (typeof (ListSelectionMode), value))
 102                                         throw new ArgumentOutOfRangeException ("value", "Only valid enumeration members are allowed");
 103                                 ViewState ["SelectionMode"] = value;
 104                         }
 105                 }
 106
 107                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
 108                 [Bindable (false), EditorBrowsable (EditorBrowsableState.Never)]
 109                 public override string ToolTip
 110                 {
 111                         get { return String.Empty; }
 112                         set { /* Don't do anything. */ }
 113                 }
 114
 115                 protected override void AddAttributesToRender (HtmlTextWriter writer)
 116                 {
 117                         if (Page != null)
 118                                 Page.VerifyRenderingInServerForm (this);
 119
 120                         writer.AddAttribute (HtmlTextWriterAttribute.Name, UniqueID);
 121                         base.AddAttributesToRender (writer);
 122                         writer.AddAttribute (HtmlTextWriterAttribute.Size,
 123                                              Rows.ToString (NumberFormatInfo.InvariantInfo));
 124
 125                         if (SelectionMode == ListSelectionMode.Multiple)
 126                                 writer.AddAttribute (HtmlTextWriterAttribute.Multiple, "multiple");
 127
 128                         if (AutoPostBack && Page != null){
 129                                 writer.AddAttribute (HtmlTextWriterAttribute.Onchange,
 130                                                      Page.GetPostBackClientEvent (this, ""));
 131                                 writer.AddAttribute ("language", "javascript");
 132                         }
 133                 }
 134
 135                 protected override void OnPreRender (EventArgs e)
 136                 {
 137                         base.OnPreRender (e);
 138                         if (Page != null && SelectionMode == ListSelectionMode.Multiple && Enabled)
 139                                 Page.RegisterRequiresPostBack(this);
 140                 }
 141
 142                 protected override void RenderContents (HtmlTextWriter writer)
 143                 {
 144                         bool isMultAllowed = (SelectionMode == ListSelectionMode.Multiple);
 145                         bool selMade = false;
 146                         foreach (ListItem current in Items){
 147                                 writer.WriteBeginTag ("option");
 148                                 if (current.Selected){
 149                                         if (!isMultAllowed && selMade)
 150                                                 throw new HttpException ("Cannot_MultiSelect_In_Single_Mode");
 151                                         selMade = true;
 152                                         writer.WriteAttribute ("selected", "selected");
 153                                 }
 154                                 writer.WriteAttribute ("value", current.Value, true);
 155                                 writer.Write ('>');
 156                                 writer.Write (HttpUtility.HtmlEncode (current.Text));
 157                                 writer.WriteEndTag ("option");
 158                                 writer.WriteLine ();
 159                         }
 160                 }
 161
 162                 bool IPostBackDataHandler.LoadPostData (string postDataKey,
 163                                                         NameValueCollection postCollection)
 164                 {
 165                         string[] vals = postCollection.GetValues (postDataKey);
 166                         bool updated = false;
 167                         if (vals != null){
 168                                 if (SelectionMode == ListSelectionMode.Single){
 169                                         int index = Items.FindByValueInternal (vals [0]);
 170                                         if (SelectedIndex != index){
 171                                                 SelectedIndex = index;
 172                                                 updated       = true;
 173                                         }
 174                                 } else {
 175                                         ArrayList indices = SelectedIndices;
 176                                         int length = vals.Length;
 177                                         ArrayList final = new ArrayList (length);
 178                                         foreach (string current in vals)
 179                                                 final.Add (Items.FindByValueInternal (current));
 180
 181                                         if (indices.Count == length) {
 182                                                 for (int ctr = 0; ctr < length; ctr++){
 183                                                         if (((int) final [ctr]) != ((int) indices [ctr])){
 184                                                                 updated = true;
 185                                                                 break;
 186                                                         }
 187                                                 }
 188                                         } else {
 189                                                 updated = true;
 190                                         }
 191                                         if (updated)
 192                                                 Select (final);
 193                                 }
 194                         } else {
 195                                 if (SelectedIndex != -1)
 196                                         SelectedIndex = -1;
 197                                 updated = true;
 198                         }
 199                         return updated;
 200                 }
 201
 202                 void IPostBackDataHandler.RaisePostDataChangedEvent ()
 203                 {
 204                         OnSelectedIndexChanged (EventArgs.Empty);
 205                 }
 206         }
 207 }