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                 bool initialized;
  45                 bool requiresDataBinding;
  46
  47                 protected BaseDataBoundControl ()
  48                 {
  49                 }
  50
  51                 /* Used for controls that used to inherit from
  52                  * WebControl, so the tag can propagate upwards
  53                  */
  54                 internal BaseDataBoundControl (HtmlTextWriterTag tag) : base (tag)
  55                 {
  56                 }
  57
  58                 [BindableAttribute (true)]
  59                 [ThemeableAttribute (false)]
  60                 [DefaultValueAttribute (null)]
  61                 [DesignerSerializationVisibilityAttribute (DesignerSerializationVisibility.Hidden)]
  62                 public virtual object DataSource {
  63                         get {
  64                                 return dataSource;
  65                         }
  66                         set {
  67                                 ValidateDataSource (value);
  68                                 dataSource = value;
  69                                 if (initialized)
  70                                         OnDataPropertyChanged ();
  71                         }
  72                 }
  73
  74                 [DefaultValueAttribute ("")]
  75                 [ThemeableAttribute (false)]
  76                 public virtual string DataSourceID {
  77                         get {
  78                                 return ViewState.GetString ("DataSourceID", "");
  79                         }
  80                         set {
  81                                 ViewState["DataSourceID"] = value;
  82                                 if (initialized)
  83                                         OnDataPropertyChanged ();
  84                         }
  85                 }
  86
  87                 protected bool Initialized {
  88                         get { return initialized; }
  89                 }
  90
  91                 protected bool IsBoundUsingDataSourceID {
  92                         get { return DataSourceID.Length > 0; }
  93                 }
  94
  95                 protected bool RequiresDataBinding {
  96                         get { return requiresDataBinding; }
  97                         set { requiresDataBinding = value; }
  98                 }
  99
 100                 protected void ConfirmInitState ()
 101                 {
 102                         initialized = true;
 103                 }
 104
 105                 public override void DataBind ()
 106                 {
 107                         RequiresDataBinding = false;
 108                         PerformSelect ();
 109                 }
 110
 111                 protected virtual void EnsureDataBound ()
 112                 {
 113                         if (RequiresDataBinding && IsBoundUsingDataSourceID)
 114                                 DataBind ();
 115                 }
 116
 117                 protected virtual void OnDataBound (EventArgs e)
 118                 {
 119                         if (DataBound != null)
 120                                 DataBound (this, e);
 121                 }
 122
 123                 protected virtual void OnDataPropertyChanged ()
 124                 {
 125                         RequiresDataBinding = true;
 126                 }
 127
 128                 protected internal override void OnInit (EventArgs e)
 129                 {
 130                         base.OnInit (e);
 131                         Page.PreLoad += new EventHandler (OnPagePreLoad);
 132                 }
 133
 134                 protected virtual void OnPagePreLoad (object sender, EventArgs e)
 135                 {
 136                         ConfirmInitState ();
 137                 }
 138
 139                 protected internal override void OnPreRender (EventArgs e)
 140                 {
 141                         EnsureDataBound ();
 142                         base.OnPreRender (e);
 143                 }
 144
 145                 protected abstract void PerformSelect ();
 146
 147                 protected abstract void ValidateDataSource (object dataSource);
 148
 149         }
 150 }
 151
 152 #endif
 153