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                 protected virtual IDataSource GetDataSource ()
  66                 {
  67                         if (IsBoundUsingDataSourceID) {
  68
  69                                 Control ctrl = FindDataSource ();
  70
  71                                 if (ctrl == null)
  72                                         throw new HttpException (string.Format ("A control with ID '{0}' could not be found.", DataSourceID));
  73                                 if (!(ctrl is IDataSource))
  74                                         throw new HttpException (string.Format ("The control with ID '{0}' is not a control of type IDataSource.", DataSourceID));
  75                                 return (IDataSource) ctrl;
  76                         }
  77
  78                         IDataSource ds = DataSource as IDataSource;
  79                         if (ds != null) return ds;
  80
  81                         IEnumerable ie = DataSourceResolver.ResolveDataSource (DataSource, DataMember);
  82                         return new CollectionDataSource (ie);
  83                 }
  84
  85                 protected virtual DataSourceView GetData ()
  86                 {
  87                         if (currentView == null)
  88                                 UpdateViewData ();
  89                         return currentView;
  90                 }
  91
  92                 DataSourceView InternalGetData ()
  93                 {
  94                         if (currentView != null)
  95                                 return currentView;
  96
  97                         if (DataSource != null && IsBoundUsingDataSourceID)
  98                                 throw new HttpException ("Control bound using both DataSourceID and DataSource properties.");
  99
 100                         IDataSource ds = GetDataSource ();
 101                         if (ds != null)
 102                                 return ds.GetView (DataMember);
 103                         else
 104                                 return null;
 105                 }
 106
 107                 protected override void OnDataPropertyChanged ()
 108                 {
 109                         base.OnDataPropertyChanged ();
 110                         currentView = null;
 111                 }
 112
 113                 protected virtual void OnDataSourceViewChanged (object sender, EventArgs e)
 114                 {
 115                         RequiresDataBinding = true;
 116                 }
 117
 118                 // MSDN: The OnPagePreLoad method is overridden by the DataBoundControl class
 119                 // to set the BaseDataBoundControl.RequiresDataBinding property to true in
 120                 // cases where the HTTP request is a postback and view state is enabled but
 121                 // the data-bound control has not yet been bound.
 122                 //
 123                 // LAMESPEC: RequiresDataBinding is also set when http request is NOT a postback -
 124                 // no matter whether view state is enabled. The correct description should be:
 125                 //
 126                 // The OnPagePreLoad method is override by the DataBoundControl class
 127                 // to set the BaseDataBoundControl.RequiresDataBinding property to true in
 128                 // cases where the HTTP request is not a postback or it is a postback and view state
 129                 // is enabled but the data-bound control has not yet been bound.
 130                 protected override void OnPagePreLoad (object sender, EventArgs e)
 131                 {
 132                         base.OnPagePreLoad (sender, e);
 133
 134                         Initialize ();
 135                 }
 136
 137                 void Initialize ()
 138                 {
 139                         Page page = Page;
 140                         if (page != null) {
 141                                 // LAMESPEC: see the comment above OnPagePreLoad
 142                                 if (!page.IsPostBack || (!IsDataBound && IsViewStateEnabled))
 143                                         RequiresDataBinding = true;
 144                         }
 145
 146                 }
 147
 148                 void UpdateViewData ()
 149                 {
 150                         if (currentView != null)
 151                                 currentView.DataSourceViewChanged -= new EventHandler (OnDataSourceViewChanged);
 152
 153                         DataSourceView view = InternalGetData ();
 154                         if (view != currentView)
 155                                 currentView = view;
 156
 157                         if (currentView != null)
 158                                 currentView.DataSourceViewChanged += new EventHandler (OnDataSourceViewChanged);
 159                 }
 160
 161                 protected internal override void OnLoad (EventArgs e)
 162                 {
 163                         UpdateViewData ();
 164                         if (!Initialized) {
 165                                 Initialize ();
 166
 167                                 // MSDN: The ConfirmInitState method sets the initialized state of the data-bound
 168                                 // control. The method is called by the DataBoundControl class in its OnLoad
 169                                 // method.
 170                                 ConfirmInitState ();
 171                         }
 172
 173                         base.OnLoad(e);
 174                 }
 175
 176                 protected internal virtual void PerformDataBinding (IEnumerable data)
 177                 {
 178                 }
 179
 180                 protected override void ValidateDataSource (object dataSource)
 181                 {
 182                         if (dataSource == null || dataSource is IListSource || dataSource is IEnumerable || dataSource is IDataSource)
 183                                 return;
 184                         throw new ArgumentException ("Invalid data source source type. The data source must be of type IListSource, IEnumerable or IDataSource.");
 185                 }
 186
 187                 [ThemeableAttribute (false)]
 188                 [DefaultValueAttribute ("")]
 189                 [WebCategoryAttribute ("Data")]
 190                 public virtual string DataMember {
 191                         get { return ViewState.GetString ("DataMember", ""); }
 192                         set { ViewState["DataMember"] = value; }
 193                 }
 194
 195                 [IDReferencePropertyAttribute (typeof(DataSourceControl))]
 196                 public override string DataSourceID {
 197                         get { return ViewState.GetString ("DataSourceID", ""); }
 198                         set {
 199                                 ViewState ["DataSourceID"] = value;
 200                                 base.DataSourceID = value;
 201                         }
 202                 }
 203
 204 #if NET_4_0
 205                 [Browsable (false)]
 206                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
 207                 public
 208 #else
 209                 internal
 210 #endif
 211                 IDataSource DataSourceObject {
 212                         get { return GetDataSource (); }
 213                 }
 214
 215                 //
 216                 // See DataBoundControl.MarkAsDataBound msdn doc for the code example
 217                 //
 218                 protected override void PerformSelect ()
 219                 {
 220                         // Call OnDataBinding here if bound to a data source using the
 221                         // DataSource property (instead of a DataSourceID), because the
 222                         // databinding statement is evaluated before the call to GetData.
 223                         if (!IsBoundUsingDataSourceID)
 224                                 OnDataBinding (EventArgs.Empty);
 225
 226                         // prevent recursive calls
 227                         RequiresDataBinding = false;
 228                         SelectArguments = CreateDataSourceSelectArguments ();
 229                         GetData ().Select (SelectArguments, new DataSourceViewSelectCallback (OnSelect));
 230
 231                         // The PerformDataBinding method has completed.
 232                         MarkAsDataBound ();
 233
 234                         // Raise the DataBound event.
 235                         OnDataBound (EventArgs.Empty);
 236                 }
 237
 238                 void OnSelect (IEnumerable data)
 239                 {
 240                         // Call OnDataBinding only if it has not already been
 241                         // called in the PerformSelect method.
 242                         if (IsBoundUsingDataSourceID) {
 243                                 OnDataBinding (EventArgs.Empty);
 244                         }
 245                         // The PerformDataBinding method binds the data in the
 246                         // retrievedData collection to elements of the data-bound control.
 247                         InternalPerformDataBinding (data);
 248                 }
 249
 250 #if NET_4_0
 251                 internal
 252 #else
 253                 protected
 254 #endif
 255                 void InternalPerformDataBinding (IEnumerable data)
 256                 {
 257                         DataBoundControlAdapter adapter = Adapter as DataBoundControlAdapter;
 258                         if (adapter != null)
 259                                 adapter.PerformDataBinding (data);
 260                         else
 261                                 PerformDataBinding (data);
 262                 }
 263
 264                 protected virtual DataSourceSelectArguments CreateDataSourceSelectArguments ()
 265                 {
 266                         return DataSourceSelectArguments.Empty;
 267                 }
 268
 269                 protected DataSourceSelectArguments SelectArguments {
 270                         get {
 271                                 if (selectArguments == null)
 272                                         selectArguments = CreateDataSourceSelectArguments ();
 273                                 return selectArguments;
 274                         }
 275                         private set {
 276                                 selectArguments = value;
 277                         }
 278                 }
 279
 280                 bool IsDataBound {
 281                         get {
 282                                 object dataBound = ViewState ["DataBound"];
 283                                 return dataBound != null ? (bool) dataBound : false;
 284                         }
 285                         set {
 286                                 ViewState ["DataBound"] = value;
 287                         }
 288                 }
 289
 290                 protected void MarkAsDataBound ()
 291                 {
 292                         IsDataBound = true;
 293                 }
 294         }
 295 }
 296 #endif
 297
 298
 299
 300
 301