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

   1 //
   2 // System.Web.UI.WebControls.BaseDataBoundControl.cs
   3 //
   4 // Authors:
   5 //      Lluis Sanchez Gual (lluis@novell.com)
   6 //
   7 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 #if NET_2_0
  30 using System.Collections;
  31 using System.ComponentModel;
  32 using System.Security.Permissions;
  33
  34 namespace System.Web.UI.WebControls {
  35
  36         // CAS
  37         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  38         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  39         // attributes
  40         [DefaultProperty ("DataSourceID")]
  41         [DesignerAttribute ("System.Web.UI.Design.WebControls.BaseDataBoundControlDesigner, " + Consts.AssemblySystem_Design, "System.ComponentModel.Design.IDesigner")]
  42         public abstract class BaseDataBoundControl: WebControl
  43         {
  44                 public event EventHandler DataBound;
  45
  46                 object dataSource;
  47                 bool initialized;
  48                 bool requiresDataBinding;
  49
  50                 protected BaseDataBoundControl ()
  51                 {
  52                 }
  53
  54                 /* Used for controls that used to inherit from
  55                  * WebControl, so the tag can propagate upwards
  56                  */
  57                 internal BaseDataBoundControl (HtmlTextWriterTag tag) : base (tag)
  58                 {
  59                 }
  60
  61                 [BindableAttribute (true)]
  62                 [ThemeableAttribute (false)]
  63                 [DefaultValueAttribute (null)]
  64                 [DesignerSerializationVisibilityAttribute (DesignerSerializationVisibility.Hidden)]
  65                 public virtual object DataSource {
  66                         get {
  67                                 return dataSource;
  68                         }
  69                         set {
  70                                 ValidateDataSource (value);
  71                                 dataSource = value;
  72                                 if (initialized)
  73                                         OnDataPropertyChanged ();
  74                         }
  75                 }
  76
  77                 [DefaultValueAttribute ("")]
  78                 [ThemeableAttribute (false)]
  79                 public virtual string DataSourceID {
  80                         get {
  81                                 return ViewState.GetString ("DataSourceID", "");
  82                         }
  83                         set {
  84                                 ViewState["DataSourceID"] = value;
  85                                 if (initialized)
  86                                         OnDataPropertyChanged ();
  87                         }
  88                 }
  89
  90                 protected bool Initialized {
  91                         get { return initialized; }
  92                 }
  93
  94                 protected bool IsBoundUsingDataSourceID {
  95                         get { return DataSourceID.Length > 0; }
  96                 }
  97
  98                 protected bool RequiresDataBinding {
  99                         get { return requiresDataBinding; }
 100                         set { requiresDataBinding = value; }
 101                 }
 102
 103                 protected void ConfirmInitState ()
 104                 {
 105                         initialized = true;
 106                 }
 107
 108                 public override void DataBind ()
 109                 {
 110                         RequiresDataBinding = false;
 111                         PerformSelect ();
 112                 }
 113
 114                 protected virtual void EnsureDataBound ()
 115                 {
 116                         if (RequiresDataBinding && IsBoundUsingDataSourceID)
 117                                 DataBind ();
 118                 }
 119
 120                 protected virtual void OnDataBound (EventArgs e)
 121                 {
 122                         if (DataBound != null)
 123                                 DataBound (this, e);
 124                 }
 125
 126                 protected virtual void OnDataPropertyChanged ()
 127                 {
 128                         RequiresDataBinding = true;
 129                 }
 130
 131                 protected internal override void OnInit (EventArgs e)
 132                 {
 133                         base.OnInit (e);
 134                         Page.PreLoad += new EventHandler (OnPagePreLoad);
 135                 }
 136
 137                 protected virtual void OnPagePreLoad (object sender, EventArgs e)
 138                 {
 139                         ConfirmInitState ();
 140                 }
 141
 142                 protected internal override void OnPreRender (EventArgs e)
 143                 {
 144                         EnsureDataBound ();
 145                         base.OnPreRender (e);
 146                 }
 147
 148                 protected abstract void PerformSelect ();
 149
 150                 protected abstract void ValidateDataSource (object dataSource);
 151
 152         }
 153 }
 154
 155 #endif
 156