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 preRendered;
  49                 bool requiresDataBinding;
  50
  51                 protected BaseDataBoundControl ()
  52                 {
  53                 }
  54
  55                 /* Used for controls that used to inherit from
  56                  * WebControl, so the tag can propagate upwards
  57                  */
  58                 internal BaseDataBoundControl (HtmlTextWriterTag tag) : base (tag)
  59                 {
  60                 }
  61
  62                 [BindableAttribute (true)]
  63                 [ThemeableAttribute (false)]
  64                 [DefaultValueAttribute (null)]
  65                 [DesignerSerializationVisibilityAttribute (DesignerSerializationVisibility.Hidden)]
  66                 public virtual object DataSource {
  67                         get {
  68                                 return dataSource;
  69                         }
  70                         set {
  71                                 ValidateDataSource (value);
  72                                 dataSource = value;
  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                                 OnDataPropertyChanged ();
  86                         }
  87                 }
  88
  89                 protected bool Initialized {
  90                         get { return initialized; }
  91                 }
  92
  93                 protected bool IsBoundUsingDataSourceID {
  94                         get { return DataSourceID.Length > 0; }
  95                 }
  96
  97                 protected bool RequiresDataBinding {
  98                         get { return requiresDataBinding; }
  99                         set {
 100                                 requiresDataBinding = value;
 101                                 if (value && preRendered && IsBoundUsingDataSourceID && Page != null && !Page.IsCallback)
 102                                         EnsureDataBound ();
 103                         }
 104                 }
 105
 106                 protected void ConfirmInitState ()
 107                 {
 108                         initialized = true;
 109                 }
 110
 111                 public override void DataBind ()
 112                 {
 113                         RequiresDataBinding = false;
 114                         PerformSelect ();
 115                 }
 116
 117                 protected virtual void EnsureDataBound ()
 118                 {
 119                         if (RequiresDataBinding && IsBoundUsingDataSourceID)
 120                                 DataBind ();
 121                 }
 122
 123                 protected virtual void OnDataBound (EventArgs e)
 124                 {
 125                         if (DataBound != null)
 126                                 DataBound (this, e);
 127                 }
 128
 129                 protected virtual void OnDataPropertyChanged ()
 130                 {
 131                         RequiresDataBinding = true;
 132                 }
 133
 134                 protected internal override void OnInit (EventArgs e)
 135                 {
 136                         base.OnInit (e);
 137                         Page.PreLoad += new EventHandler (OnPagePreLoad);
 138
 139                         if (!IsViewStateEnabled && Page != null && Page.IsPostBack)
 140                                 RequiresDataBinding = true;
 141                 }
 142
 143                 protected virtual void OnPagePreLoad (object sender, EventArgs e)
 144                 {
 145                         ConfirmInitState ();
 146                 }
 147
 148                 protected internal override void OnPreRender (EventArgs e)
 149                 {
 150                         preRendered = true;
 151                         EnsureDataBound ();
 152                         base.OnPreRender (e);
 153                 }
 154
 155                 protected abstract void PerformSelect ();
 156
 157                 protected abstract void ValidateDataSource (object dataSource);
 158
 159         }
 160 }
 161
 162 #endif
 163