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