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

   1 //
   2 // System.Web.UI.WebControls.DataBoundControl
   3 //
   4 // Authors:
   5 //      Ben Maurer (bmaurer@users.sourceforge.net)
   6 //      Sanjay Gupta (gsanjay@novell.com)
   7 //
   8 // (C) 2003 Ben Maurer
   9 // (C) 2004 Novell, Inc. (http://www.novell.com)
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 #if NET_2_0
  34 using System.Collections;
  35 using System.Collections.Specialized;
  36 using System.Text;
  37 using System.Web.Util;
  38 using System.ComponentModel;
  39 using System.Security.Permissions;
  40 using System.Web.UI.WebControls.Adapters;
  41
  42 namespace System.Web.UI.WebControls {
  43
  44         // CAS
  45         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  46         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  47         // attributes
  48         [DesignerAttribute ("System.Web.UI.Design.WebControls.DataBoundControlDesigner, " + Consts.AssemblySystem_Design, "System.ComponentModel.Design.IDesigner")]
  49         public abstract class DataBoundControl : BaseDataBoundControl
  50         {
  51                 DataSourceSelectArguments selectArguments;
  52                 DataSourceView currentView;
  53
  54                 protected DataBoundControl ()
  55                 {
  56                 }
  57
  58                 /* Used for controls that used to inherit from
  59                  * WebControl, so the tag can propagate upwards
  60                  */
  61                 internal DataBoundControl (HtmlTextWriterTag tag) : base (tag)
  62                 {
  63                 }
  64
  65
  66                 protected virtual IDataSource GetDataSource ()
  67                 {
  68                         if (IsBoundUsingDataSourceID) {
  69
  70                                 Control ctrl = FindDataSource ();
  71
  72                                 if (ctrl == null)
  73                                         throw new HttpException (string.Format ("A control with ID '{0}' could not be found.", DataSourceID));
  74                                 if (!(ctrl is IDataSource))
  75                                         throw new HttpException (string.Format ("The control with ID '{0}' is not a control of type IDataSource.", DataSourceID));
  76                                 return (IDataSource) ctrl;
  77                         }
  78
  79                         IDataSource ds = DataSource as IDataSource;
  80                         if (ds != null) return ds;
  81
  82                         IEnumerable ie = DataSourceResolver.ResolveDataSource (DataSource, DataMember);
  83                         return new CollectionDataSource (ie);
  84                 }
  85
  86                 protected virtual DataSourceView GetData ()
  87                 {
  88                         if (currentView == null)
  89                                 UpdateViewData ();
  90                         return currentView;
  91                 }
  92
  93                 DataSourceView InternalGetData ()
  94                 {
  95                         if (DataSource != null && IsBoundUsingDataSourceID)
  96                                 throw new HttpException ("Control bound using both DataSourceID and DataSource properties.");
  97
  98                         IDataSource ds = GetDataSource ();
  99                         if (ds != null)
 100                                 return ds.GetView (DataMember);
 101                         else
 102                                 return null;
 103                 }
 104
 105                 protected override void OnDataPropertyChanged ()
 106                 {
 107                         base.OnDataPropertyChanged ();
 108                         currentView = null;
 109                 }
 110
 111                 protected virtual void OnDataSourceViewChanged (object sender, EventArgs e)
 112                 {
 113                         RequiresDataBinding = true;
 114                 }
 115
 116                 // MSDN: The OnPagePreLoad method is overridden by the DataBoundControl class
 117                 // to set the BaseDataBoundControl.RequiresDataBinding property to true in
 118                 // cases where the HTTP request is a postback and view state is enabled but
 119                 // the data-bound control has not yet been bound.
 120                 protected override void OnPagePreLoad (object sender, EventArgs e)
 121                 {
 122                         base.OnPagePreLoad (sender, e);
 123
 124                         Initialize ();
 125                 }
 126
 127                 private void Initialize ()
 128                 {
 129                         if (!IsDataBound)
 130                                 RequiresDataBinding = true;
 131
 132                         UpdateViewData ();
 133                 }
 134
 135                 void UpdateViewData ()
 136                 {
 137                         DataSourceView view = InternalGetData ();
 138                         if (view == currentView) return;
 139
 140                         if (currentView != null)
 141                                 currentView.DataSourceViewChanged -= new EventHandler (OnDataSourceViewChanged);
 142
 143                         currentView = view;
 144
 145                         if (view != null)
 146                                 view.DataSourceViewChanged += new EventHandler (OnDataSourceViewChanged);
 147                 }
 148
 149                 protected internal override void OnLoad (EventArgs e)
 150                 {
 151                         if (!Initialized) {
 152
 153                                 Initialize ();
 154
 155                                 // MSDN: The ConfirmInitState method sets the initialized state of the data-bound
 156                                 // control. The method is called by the DataBoundControl class in its OnLoad method.
 157                                 ConfirmInitState ();
 158                         }
 159                         base.OnLoad(e);
 160                 }
 161
 162                 protected internal virtual void PerformDataBinding (IEnumerable data)
 163                 {
 164                 }
 165
 166                 protected override void ValidateDataSource (object dataSource)
 167                 {
 168                         if (dataSource == null || dataSource is IListSource || dataSource is IEnumerable || dataSource is IDataSource)
 169                                 return;
 170                         throw new ArgumentException ("Invalid data source source type. The data source must be of type IListSource, IEnumerable or IDataSource.");
 171                 }
 172
 173                 [ThemeableAttribute (false)]
 174                 [DefaultValueAttribute ("")]
 175                 [WebCategoryAttribute ("Data")]
 176                 public virtual string DataMember {
 177                         get { return ViewState.GetString ("DataMember", ""); }
 178                         set { ViewState["DataMember"] = value; }
 179                 }
 180
 181                 [IDReferencePropertyAttribute (typeof(DataSourceControl))]
 182                 public override string DataSourceID {
 183                         get { return ViewState.GetString ("DataSourceID", ""); }
 184                         set {
 185                                 ViewState ["DataSourceID"] = value;
 186                                 base.DataSourceID = value;
 187                         }
 188                 }
 189
 190                 //
 191                 // See DataBoundControl.MarkAsDataBound msdn doc for the code example
 192                 //
 193                 protected override void PerformSelect ()
 194                 {
 195                         // Call OnDataBinding here if bound to a data source using the
 196                         // DataSource property (instead of a DataSourceID), because the
 197                         // databinding statement is evaluated before the call to GetData.
 198                         if (!IsBoundUsingDataSourceID)
 199                                 OnDataBinding (EventArgs.Empty);
 200
 201                         // prevent recursive calls
 202                         RequiresDataBinding = false;
 203                         SelectArguments = CreateDataSourceSelectArguments ();
 204                         GetData ().Select (SelectArguments, new DataSourceViewSelectCallback (OnSelect));
 205
 206                         // The PerformDataBinding method has completed.
 207                         MarkAsDataBound ();
 208
 209                         // Raise the DataBound event.
 210                         OnDataBound (EventArgs.Empty);
 211                 }
 212
 213                 void OnSelect (IEnumerable data)
 214                 {
 215                         // Call OnDataBinding only if it has not already been
 216                         // called in the PerformSelect method.
 217                         if (IsBoundUsingDataSourceID) {
 218                                 OnDataBinding (EventArgs.Empty);
 219                         }
 220                         // The PerformDataBinding method binds the data in the
 221                         // retrievedData collection to elements of the data-bound control.
 222                         InternalPerformDataBinding (data);
 223                 }
 224
 225                 protected void InternalPerformDataBinding (IEnumerable data)
 226                 {
 227                         DataBoundControlAdapter adapter = (DataBoundControlAdapter)Adapter;
 228                         if (adapter != null)
 229                                 adapter.PerformDataBinding (data);
 230                         else
 231                                 PerformDataBinding (data);
 232                 }
 233
 234                 protected virtual DataSourceSelectArguments CreateDataSourceSelectArguments ()
 235                 {
 236                         return DataSourceSelectArguments.Empty;
 237                 }
 238
 239                 protected DataSourceSelectArguments SelectArguments {
 240                         get {
 241                                 if (selectArguments == null)
 242                                         selectArguments = CreateDataSourceSelectArguments ();
 243                                 return selectArguments;
 244                         }
 245                         private set {
 246                                 selectArguments = value;
 247                         }
 248                 }
 249
 250                 bool IsDataBound {
 251                         get {
 252                                 object dataBound = ViewState ["DataBound"];
 253                                 return dataBound != null ? (bool) dataBound : false;
 254                         }
 255                         set {
 256                                 ViewState ["DataBound"] = value;
 257                         }
 258                 }
 259
 260                 protected void MarkAsDataBound ()
 261                 {
 262                         IsDataBound = true;
 263                 }
 264         }
 265 }
 266 #endif
 267
 268
 269
 270
 271