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

   1 /**
   2  * Namespace: System.Web.UI.WebControls
   3  * Class:     Button
   4  *
   5  * Author:  Gaurav Vaish
   6  * Maintainer: gvaish@iitk.ac.in
   7  * Contact: <my_scripts2001@yahoo.com>, <gvaish@iitk.ac.in>
   8  * Implementation: yes
   9  * Status:  100%
  10  *
  11  * (C) Gaurav Vaish (2001)
  12  */
  13
  14 using System;
  15 using System.ComponentModel;
  16 using System.Web;
  17 using System.Web.UI;
  18
  19 namespace System.Web.UI.WebControls
  20 {
  21         [DefaultEvent("Click")]
  22         [DefaultProperty("Text")]
  23         //TODO: [Designer("??")]
  24         //TODO: [DataBindingHandler("??UI.Design.TextDataBindingHandler??")]
  25         [ToolboxData("<{0}:Button runat=\"server\" Text=\"Button\"></{0}:Button>")]
  26         public class Button : WebControl, IPostBackEventHandler
  27         {
  28                 private static readonly object ClickEvent   = new object();
  29                 private static readonly object CommandEvent = new object();
  30
  31                 //private EventHandlerList ehList;
  32
  33                 public Button(): base (HtmlTextWriterTag.Input)
  34                 {
  35                 }
  36
  37                 public bool CausesValidation
  38                 {
  39                         get
  40                         {
  41                                 Object cv = ViewState["CausesValidation"];
  42                                 if(cv!=null)
  43                                         return (Boolean)cv;
  44                                 return true;
  45                         }
  46                         set
  47                         {
  48                                 ViewState["CausesValidation"] = value;
  49                         }
  50                 }
  51
  52                 public string CommandArgument
  53                 {
  54                         get
  55                         {
  56                                 string ca = (string) ViewState["CommandArgument"];
  57                                 if(ca!=null)
  58                                         return ca;
  59                                 return String.Empty;
  60                         }
  61                         set
  62                         {
  63                                 ViewState["CommandArgument"] = value;
  64                         }
  65                 }
  66
  67                 public string CommandName
  68                 {
  69                         get
  70                         {
  71                                 string cn = (string)ViewState["CommandName"];
  72                                 if(cn!=null)
  73                                         return cn;
  74                                 return String.Empty;
  75                         }
  76                         set
  77                         {
  78                                 ViewState["CommandName"] = value;
  79                         }
  80                 }
  81
  82                 public string Text
  83                 {
  84                         get
  85                         {
  86                                 string text = (string)ViewState["Text"];
  87                                 if(text!=null)
  88                                         return text;
  89                                 return String.Empty;
  90                         }
  91                         set
  92                         {
  93                                 ViewState["Text"] = value;
  94                         }
  95                 }
  96
  97                 public event EventHandler Click
  98                 {
  99                         add
 100                         {
 101                                 Events.AddHandler(ClickEvent, value);
 102                         }
 103                         remove
 104                         {
 105                                 Events.RemoveHandler(ClickEvent, value);
 106                         }
 107                 }
 108
 109                 public event CommandEventHandler Command
 110                 {
 111                         add
 112                         {
 113                                 Events.AddHandler(CommandEvent, value);
 114                         }
 115                         remove
 116                         {
 117                                 Events.RemoveHandler(CommandEvent, value);
 118                         }
 119                 }
 120
 121                 protected virtual void OnClick(EventArgs e)
 122                 {
 123                         if(Events != null)
 124                         {
 125                                 EventHandler eh = (EventHandler)(Events[ClickEvent]);
 126                                 if(eh!= null)
 127                                         eh(this,e);
 128                         }
 129                 }
 130
 131                 protected virtual void OnCommand(CommandEventArgs e)
 132                 {
 133                         if(Events != null)
 134                         {
 135                                 CommandEventHandler eh = (CommandEventHandler)(Events[CommandEvent]);
 136                                 if(eh!= null)
 137                                         eh(this,e);
 138                         }
 139                         RaiseBubbleEvent(this, e);
 140                 }
 141
 142                 void IPostBackEventHandler.RaisePostBackEvent (string eventArgument)
 143                 {
 144                         if (CausesValidation)
 145                                 Page.Validate ();
 146
 147                         OnClick (EventArgs.Empty);
 148                         OnCommand (new CommandEventArgs (CommandName, CommandArgument));
 149                 }
 150
 151                 protected override void AddAttributesToRender (HtmlTextWriter writer)
 152                 {
 153                         if (Page != null)
 154                                 Page.VerifyRenderingInServerForm (this);
 155
 156                         writer.AddAttribute (HtmlTextWriterAttribute.Type, "submit");
 157                         writer.AddAttribute (HtmlTextWriterAttribute.Name, base.UniqueID);
 158                         writer.AddAttribute (HtmlTextWriterAttribute.Value, Text);
 159                         if (Page != null && CausesValidation && Page.Validators.Count > 0) {
 160                                 writer.AddAttribute (System.Web.UI.HtmlTextWriterAttribute.Onclick,
 161                                                      Utils.GetClientValidatedEvent (Page));
 162                                 writer.AddAttribute ("language", "javascript");
 163                         }
 164                         base.AddAttributesToRender (writer);
 165                 }
 166
 167                 protected override void RenderContents(HtmlTextWriter writer)
 168                 {
 169                         // Preventing base classes to do anything
 170                 }
 171         }
 172 }