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, System.Design, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", "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                 [BindableAttribute (true)]
  49                 [ThemeableAttribute (false)]
  50                 [DefaultValueAttribute (null)]
  51                 [DesignerSerializationVisibilityAttribute (DesignerSerializationVisibility.Hidden)]
  52                 public virtual object DataSource {
  53                         get {
  54                                 return dataSource;
  55                         }
  56                         set {
  57                                 ValidateDataSource (value);
  58                                 dataSource = value;
  59                                 if (initialized)
  60                                         OnDataPropertyChanged ();
  61                         }
  62                 }
  63
  64                 [DefaultValueAttribute ("")]
  65                 [ThemeableAttribute (false)]
  66                 public virtual string DataSourceID {
  67                         get {
  68                                 return dataSourceId != null ? dataSourceId : string.Empty;
  69                         }
  70                         set {
  71                                 dataSourceId = value;
  72                                 if (initialized)
  73                                         OnDataPropertyChanged ();
  74                         }
  75                 }
  76
  77                 protected bool Initialized {
  78                         get { return initialized; }
  79                 }
  80
  81                 protected bool IsBoundUsingDataSourceID {
  82                         get { return DataSourceID.Length > 0; }
  83                 }
  84
  85                 protected bool RequiresDataBinding {
  86                         get { return requiresDataBinding; }
  87                         set { requiresDataBinding = value; }
  88                 }
  89
  90                 protected void ConfirmInitState ()
  91                 {
  92                         initialized = true;
  93                 }
  94
  95                 public override void DataBind ()
  96                 {
  97                         RequiresDataBinding = false;
  98                         PerformSelect ();
  99                         base.DataBind ();
 100                         OnDataBound (EventArgs.Empty);
 101                 }
 102
 103                 protected virtual void EnsureDataBound ()
 104                 {
 105                         if (RequiresDataBinding && IsBoundUsingDataSourceID)
 106                                 DataBind ();
 107                 }
 108
 109                 protected virtual void OnDataBound (EventArgs e)
 110                 {
 111                         if (DataBound != null)
 112                                 DataBound (this, e);
 113                 }
 114
 115                 protected virtual void OnDataPropertyChanged ()
 116                 {
 117                         RequiresDataBinding = true;
 118                 }
 119
 120                 protected override void OnInit (EventArgs e)
 121                 {
 122                         base.OnInit (e);
 123                         Page.PreLoad += new EventHandler (OnPagePreLoad);
 124                 }
 125
 126                 protected virtual void OnPagePreLoad (object sender, EventArgs e)
 127                 {
 128                         ConfirmInitState ();
 129                 }
 130
 131                 protected override void OnPreRender (EventArgs e)
 132                 {
 133                         EnsureDataBound ();
 134                         base.OnPreRender (e);
 135                 }
 136
 137                 protected abstract void PerformSelect ();
 138
 139                 protected abstract void ValidateDataSource (object dataSource);
 140
 141         }
 142 }
 143
 144 #endif
 145