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

   1 //
   2 // System.Web.UI.WebControls.DropDownList.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 //\r
  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 \r
  33 using System;\r
  34 using System.Collections.Specialized;\r
  35 using System.ComponentModel;\r
  36 using System.Drawing;\r
  37 using System.Web;\r
  38 using System.Web.UI;\r
  39 \r
  40 namespace System.Web.UI.WebControls\r
  41 {\r
  42         [ValidationProperty("SelectedItem")]\r
  43         public class DropDownList : ListControl, IPostBackDataHandler\r
  44         {\r
  45                 public DropDownList(): base()\r
  46                 {\r
  47                 }\r
  48
  49                 [Browsable (false)]\r
  50                 public override Color BorderColor\r
  51                 {\r
  52                         get\r
  53                         {\r
  54                                 return base.BorderColor;\r
  55                         }\r
  56                         set\r
  57                         {\r
  58                                 base.BorderColor = value;\r
  59                         }\r
  60                 }\r
  61
  62                 [Browsable (false)]\r
  63                 public override BorderStyle BorderStyle\r
  64                 {\r
  65                         get\r
  66                         {\r
  67                                 return base.BorderStyle;\r
  68                         }\r
  69                         set\r
  70                         {\r
  71                                 base.BorderStyle = value;\r
  72                         }\r
  73                 }\r
  74
  75                 [Browsable (false)]\r
  76                 public override Unit BorderWidth\r
  77                 {\r
  78                         get\r
  79                         {\r
  80                                 return base.BorderWidth;\r
  81                         }\r
  82                         set\r
  83                         {\r
  84                                 base.BorderWidth = value;\r
  85                         }\r
  86                 }\r
  87
  88                 [DefaultValue (0), WebCategory ("Misc")]
  89                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  90                 [WebSysDescription ("The index number of the currently selected ListItem.")]\r
  91                 public override int SelectedIndex\r
  92                 {\r
  93                         get\r
  94                         {\r
  95                                 int index  = base.SelectedIndex;\r
  96                                 if (index < 0 && Items.Count > 0) {\r
  97                                         index = 0;\r
  98                                         Items [0].Selected = true;\r
  99                                 }\r
 100                                 return index;\r
 101                         }\r
 102                         set\r
 103                         {\r
 104                                 base.SelectedIndex = value;\r
 105                         }\r
 106                 }\r
 107
 108                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
 109                 [Bindable (false), EditorBrowsable (EditorBrowsableState.Never)]\r
 110                 public override string ToolTip\r
 111                 {\r
 112                         // MS ignores the tooltip for this one\r
 113                         get {\r
 114                                 return String.Empty;\r
 115                         }\r
 116                         set {\r
 117                         }\r
 118                 }\r
 119 \r
 120                 protected override void AddAttributesToRender(HtmlTextWriter writer)\r
 121                 {\r
 122                         if(Page != null)\r
 123                         {\r
 124                                 Page.VerifyRenderingInServerForm(this);\r
 125                         }\r
 126                         writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID);\r
 127                         base.AddAttributesToRender(writer);\r
 128 \r
 129                         if(AutoPostBack && Page != null)\r
 130                         {\r
 131                                 writer.AddAttribute(HtmlTextWriterAttribute.Onchange, Page.GetPostBackClientEvent(this,""));\r
 132                                 writer.AddAttribute("language", "javascript");\r
 133                         }\r
 134                 }\r
 135 \r
 136                 protected override ControlCollection CreateControlCollection()\r
 137                 {\r
 138                         return new EmptyControlCollection(this);\r
 139                 }\r
 140 \r
 141                 protected override void RenderContents(HtmlTextWriter writer)\r
 142                 {\r
 143                         if(Items != null)\r
 144                         {\r
 145                                 bool selected = false;\r
 146                                 foreach(ListItem current in Items)\r
 147                                 {\r
 148                                         writer.WriteBeginTag("option");\r
 149                                         if(current.Selected)\r
 150                                         {\r
 151                                                 if(selected)\r
 152                                                 {\r
 153                                                         throw new HttpException(HttpRuntime.FormatResourceString("Cannot_Multiselect_In_DropDownList"));\r
 154                                                 }\r
 155                                                 selected = true;\r
 156                                                 writer.WriteAttribute("selected", "selected", false);\r
 157                                         }\r
 158                                         writer.WriteAttribute("value", current.Value, true);\r
 159                                         writer.Write('>');\r
 160                                         HttpUtility.HtmlEncode(current.Text, writer);\r
 161                                         writer.WriteEndTag("option");\r
 162                                         writer.WriteLine();\r
 163                                 }\r
 164                         }\r
 165                 }\r
 166 \r
 167                 bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)\r
 168                 {\r
 169                         string[] vals = postCollection.GetValues(postDataKey);\r
 170                         if(vals != null)\r
 171                         {\r
 172                                 int index = Items.FindByValueInternal(vals[0]);\r
 173                                 if(index != SelectedIndex)\r
 174                                 {\r
 175                                         SelectedIndex = index;\r
 176                                         return true;\r
 177                                 }\r
 178                         }\r
 179                         return false;\r
 180                 }\r
 181 \r
 182                 void IPostBackDataHandler.RaisePostDataChangedEvent()\r
 183                 {\r
 184                         OnSelectedIndexChanged(EventArgs.Empty);\r
 185                 }\r
 186         }\r
 187 }\r