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

   1 //
   2 // System.Web.UI.WebControls.Button.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 using System;
  13 using System.ComponentModel;
  14 using System.ComponentModel.Design;
  15 using System.Web;
  16 using System.Web.UI;
  17
  18 namespace System.Web.UI.WebControls
  19 {
  20         [DefaultEvent("Click")]
  21         [DefaultProperty("Text")]
  22         [Designer("System.Web.UI.Design.WebControls.ButtonDesigner, " + Consts.AssemblySystem_Design, typeof (IDesigner))]\r
  23         [DataBindingHandler("System.Web.UI.Design.TextDataBindingHandler, " + Consts.AssemblySystem_Design)]
  24         [ToolboxData("<{0}:Button runat=\"server\" Text=\"Button\"></{0}:Button>")]
  25         public class Button : WebControl, IPostBackEventHandler
  26         {
  27                 private static readonly object ClickEvent   = new object();
  28                 private static readonly object CommandEvent = new object();
  29
  30                 //private EventHandlerList ehList;
  31
  32                 public Button(): base (HtmlTextWriterTag.Input)
  33                 {
  34                 }
  35
  36                 [DefaultValue (true), Bindable (false), WebCategory ("Behavior")]
  37                 [WebSysDescription ("Determines if validation is performed when clicked.")]
  38                 public bool CausesValidation
  39                 {
  40                         get
  41                         {
  42                                 Object cv = ViewState["CausesValidation"];
  43                                 if(cv!=null)
  44                                         return (Boolean)cv;
  45                                 return true;
  46                         }
  47                         set
  48                         {
  49                                 ViewState["CausesValidation"] = value;
  50                         }
  51                 }
  52
  53                 [DefaultValue (""), Bindable (true), WebCategory ("Behavior")]
  54                 [WebSysDescription ("An argument for the Command of this control.")]
  55                 public string CommandArgument
  56                 {
  57                         get
  58                         {
  59                                 string ca = (string) ViewState["CommandArgument"];
  60                                 if(ca!=null)
  61                                         return ca;
  62                                 return String.Empty;
  63                         }
  64                         set
  65                         {
  66                                 ViewState["CommandArgument"] = value;
  67                         }
  68                 }
  69
  70                 [DefaultValue (""), WebCategory ("Behavior")]
  71                 [WebSysDescription ("The name of the Command of this control.")]
  72                 public string CommandName
  73                 {
  74                         get
  75                         {
  76                                 string cn = (string)ViewState["CommandName"];
  77                                 if(cn!=null)
  78                                         return cn;
  79                                 return String.Empty;
  80                         }
  81                         set
  82                         {
  83                                 ViewState["CommandName"] = value;
  84                         }
  85                 }
  86
  87                 [DefaultValue (""), Bindable (true), WebCategory ("Appearance")]
  88                 [WebSysDescription ("The text that should be shown on this Button.")]
  89                 public string Text
  90                 {
  91                         get
  92                         {
  93                                 string text = (string)ViewState["Text"];
  94                                 if(text!=null)
  95                                         return text;
  96                                 return String.Empty;
  97                         }
  98                         set
  99                         {
 100                                 ViewState["Text"] = value;
 101                         }
 102                 }
 103
 104                 [WebCategory ("Action")]
 105                 [WebSysDescription ("Raised when the Button is clicked.")]
 106                 public event EventHandler Click
 107                 {
 108                         add
 109                         {
 110                                 Events.AddHandler(ClickEvent, value);
 111                         }
 112                         remove
 113                         {
 114                                 Events.RemoveHandler(ClickEvent, value);
 115                         }
 116                 }
 117
 118                 [WebCategory ("Action")]
 119                 [WebSysDescription ("Raised when a Button Command is executed.")]
 120                 public event CommandEventHandler Command
 121                 {
 122                         add
 123                         {
 124                                 Events.AddHandler(CommandEvent, value);
 125                         }
 126                         remove
 127                         {
 128                                 Events.RemoveHandler(CommandEvent, value);
 129                         }
 130                 }
 131
 132                 protected virtual void OnClick(EventArgs e)
 133                 {
 134                         if(Events != null)
 135                         {
 136                                 EventHandler eh = (EventHandler)(Events[ClickEvent]);
 137                                 if(eh!= null)
 138                                         eh(this,e);
 139                         }
 140                 }
 141
 142                 protected virtual void OnCommand(CommandEventArgs e)
 143                 {
 144                         if(Events != null)
 145                         {
 146                                 CommandEventHandler eh = (CommandEventHandler)(Events[CommandEvent]);
 147                                 if(eh!= null)
 148                                         eh(this,e);
 149                         }
 150                         RaiseBubbleEvent(this, e);
 151                 }
 152
 153                 void IPostBackEventHandler.RaisePostBackEvent (string eventArgument)
 154                 {
 155                         if (CausesValidation)
 156                                 Page.Validate ();
 157
 158                         OnClick (EventArgs.Empty);
 159                         OnCommand (new CommandEventArgs (CommandName, CommandArgument));
 160                 }
 161
 162                 protected override void AddAttributesToRender (HtmlTextWriter writer)
 163                 {
 164                         if (Page != null)
 165                                 Page.VerifyRenderingInServerForm (this);
 166
 167                         writer.AddAttribute (HtmlTextWriterAttribute.Type, "submit");
 168                         writer.AddAttribute (HtmlTextWriterAttribute.Name, base.UniqueID);
 169                         writer.AddAttribute (HtmlTextWriterAttribute.Value, Text);
 170                         if (Page != null && CausesValidation && Page.Validators.Count > 0) {
 171                                 writer.AddAttribute (System.Web.UI.HtmlTextWriterAttribute.Onclick,
 172                                                      Utils.GetClientValidatedEvent (Page));
 173                                 writer.AddAttribute ("language", "javascript");
 174                         }
 175                         base.AddAttributesToRender (writer);
 176                 }
 177
 178                 protected override void RenderContents(HtmlTextWriter writer)
 179                 {
 180                         // Preventing base classes to do anything
 181                 }
 182         }
 183 }