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) 2004-2010 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 using System.Collections;
  34 using System.Collections.Specialized;
  35 using System.Text;
  36 using System.Web.Util;
  37 using System.ComponentModel;
  38 using System.Security.Permissions;
  39 using System.Web.UI.WebControls.Adapters;
  40
  41 namespace System.Web.UI.WebControls
  42 {
  43         // CAS
  44         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  45         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  46         // attributes
  47         [DesignerAttribute ("System.Web.UI.Design.WebControls.DataBoundControlDesigner, " + Consts.AssemblySystem_Design, "System.ComponentModel.Design.IDesigner")]
  48         public abstract class DataBoundControl : BaseDataBoundControl
  49         {
  50                 DataSourceSelectArguments selectArguments;
  51                 DataSourceView currentView;
  52
  53                 protected DataBoundControl ()
  54                 {
  55                 }
  56
  57                 /* Used for controls that used to inherit from
  58                  * WebControl, so the tag can propagate upwards
  59                  */
  60                 internal DataBoundControl (HtmlTextWriterTag tag) : base (tag)
  61                 {
  62                 }
  63
  64                 protected virtual IDataSource GetDataSource ()
  65                 {
  66                         if (IsBoundUsingDataSourceID) {
  67                                 Control ctrl = FindDataSource ();
  68
  69                                 if (ctrl == null)
  70                                         throw new HttpException (string.Format ("A control with ID '{0}' could not be found.", DataSourceID));
  71                                 if (!(ctrl is IDataSource))
  72                                         throw new HttpException (string.Format ("The control with ID '{0}' is not a control of type IDataSource.", DataSourceID));
  73                                 return (IDataSource) ctrl;
  74                         }
  75
  76                         IDataSource ds = DataSource as IDataSource;
  77                         if (ds != null)
  78                                 return ds;
  79
  80                         IEnumerable ie = DataSourceResolver.ResolveDataSource (DataSource, DataMember);
  81                         return new CollectionDataSource (ie);
  82                 }
  83
  84                 protected virtual DataSourceView GetData ()
  85                 {
  86                         if (currentView == null)
  87                                 UpdateViewData ();
  88                         return currentView;
  89                 }
  90
  91                 DataSourceView InternalGetData ()
  92                 {
  93                         if (currentView != null)
  94                                 return currentView;
  95
  96                         if (DataSource != null && IsBoundUsingDataSourceID)
  97                                 throw new HttpException ("Control bound using both DataSourceID and DataSource properties.");
  98
  99                         IDataSource ds = GetDataSource ();
 100                         if (ds != null)
 101                                 return ds.GetView (DataMember);
 102                         else
 103                                 return null;
 104                 }
 105
 106                 protected override void OnDataPropertyChanged ()
 107                 {
 108                         base.OnDataPropertyChanged ();
 109                         currentView = null;
 110                 }
 111
 112                 protected virtual void OnDataSourceViewChanged (object sender, EventArgs e)
 113                 {
 114                         RequiresDataBinding = true;
 115                 }
 116
 117                 // MSDN: The OnPagePreLoad method is overridden by the DataBoundControl class
 118                 // to set the BaseDataBoundControl.RequiresDataBinding property to true in
 119                 // cases where the HTTP request is a postback and view state is enabled but
 120                 // the data-bound control has not yet been bound.
 121                 //
 122                 // LAMESPEC: RequiresDataBinding is also set when http request is NOT a postback -
 123                 // no matter whether view state is enabled. The correct description should be:
 124                 //
 125                 // The OnPagePreLoad method is override by the DataBoundControl class
 126                 // to set the BaseDataBoundControl.RequiresDataBinding property to true in
 127                 // cases where the HTTP request is not a postback or it is a postback and view state
 128                 // is enabled but the data-bound control has not yet been bound.
 129                 protected override void OnPagePreLoad (object sender, EventArgs e)
 130                 {
 131                         base.OnPagePreLoad (sender, e);
 132
 133                         Initialize ();
 134                 }
 135
 136                 void Initialize ()
 137                 {
 138                         Page page = Page;
 139                         if (page != null && !IsDataBound) {
 140                                 // LAMESPEC: see the comment above OnPagePreLoad
 141                                 if (!page.IsPostBack)
 142                                         RequiresDataBinding = true;
 143                                 else if (IsViewStateEnabled)
 144                                         RequiresDataBinding = true;
 145                         }
 146
 147                 }
 148
 149                 void UpdateViewData ()
 150                 {
 151                         if (currentView != null)
 152                                 currentView.DataSourceViewChanged -= new EventHandler (OnDataSourceViewChanged);
 153
 154                         DataSourceView view = InternalGetData ();
 155                         if (view != currentView)
 156                                 currentView = view;
 157
 158                         if (currentView != null)
 159                                 currentView.DataSourceViewChanged += new EventHandler (OnDataSourceViewChanged);
 160                 }
 161
 162                 protected internal override void OnLoad (EventArgs e)
 163                 {
 164                         UpdateViewData ();
 165                         if (!Initialized) {
 166                                 Initialize ();
 167
 168                                 // MSDN: The ConfirmInitState method sets the initialized state of the data-bound
 169                                 // control. The method is called by the DataBoundControl class in its OnLoad
 170                                 // method.
 171                                 ConfirmInitState ();
 172                         }
 173
 174                         base.OnLoad(e);
 175                 }
 176
 177                 protected internal virtual void PerformDataBinding (IEnumerable data)
 178                 {
 179                 }
 180
 181                 protected override void ValidateDataSource (object dataSource)
 182                 {
 183                         if (dataSource == null || dataSource is IListSource || dataSource is IEnumerable || dataSource is IDataSource)
 184                                 return;
 185                         throw new ArgumentException ("Invalid data source source type. The data source must be of type IListSource, IEnumerable or IDataSource.");
 186                 }
 187
 188                 [ThemeableAttribute (false)]
 189                 [DefaultValueAttribute ("")]
 190                 [WebCategoryAttribute ("Data")]
 191                 public virtual string DataMember {
 192                         get { return ViewState.GetString ("DataMember", String.Empty); }
 193                         set { ViewState["DataMember"] = value; }
 194                 }
 195
 196                 [IDReferencePropertyAttribute (typeof(DataSourceControl))]
 197                 public override string DataSourceID {
 198                         get { return ViewState.GetString ("DataSourceID", String.Empty); }
 199                         set {
 200                                 ViewState ["DataSourceID"] = value;
 201                                 base.DataSourceID = value;
 202                         }
 203                 }
 204
 205                 [Browsable (false)]
 206                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
 207                 public IDataSource DataSourceObject {
 208                         get { return GetDataSource (); }
 209                 }
 210
 211                 //
 212                 // See DataBoundControl.MarkAsDataBound msdn doc for the code example
 213                 //
 214                 protected override void PerformSelect ()
 215                 {
 216                         // Call OnDataBinding here if bound to a data source using the
 217                         // DataSource property (instead of a DataSourceID), because the
 218                         // databinding statement is evaluated before the call to GetData.
 219                         if (!IsBoundUsingDataSourceID)
 220                                 OnDataBinding (EventArgs.Empty);
 221
 222                         // prevent recursive calls
 223                         RequiresDataBinding = false;
 224                         SelectArguments = CreateDataSourceSelectArguments ();
 225                         GetData ().Select (SelectArguments, new DataSourceViewSelectCallback (OnSelect));
 226
 227                         // The PerformDataBinding method has completed.
 228                         MarkAsDataBound ();
 229
 230                         // Raise the DataBound event.
 231                         OnDataBound (EventArgs.Empty);
 232                 }
 233
 234                 void OnSelect (IEnumerable data)
 235                 {
 236                         // Call OnDataBinding only if it has not already been
 237                         // called in the PerformSelect method.
 238                         if (IsBoundUsingDataSourceID)
 239                                 OnDataBinding (EventArgs.Empty);
 240                         // The PerformDataBinding method binds the data in the
 241                         // retrievedData collection to elements of the data-bound control.
 242                         InternalPerformDataBinding (data);
 243                 }
 244
 245                 internal void InternalPerformDataBinding (IEnumerable data)
 246                 {
 247                         DataBoundControlAdapter adapter = Adapter as DataBoundControlAdapter;
 248                         if (adapter != null)
 249                                 adapter.PerformDataBinding (data);
 250                         else
 251                                 PerformDataBinding (data);
 252                 }
 253
 254                 protected virtual DataSourceSelectArguments CreateDataSourceSelectArguments ()
 255                 {
 256                         return DataSourceSelectArguments.Empty;
 257                 }
 258
 259                 protected DataSourceSelectArguments SelectArguments {
 260                         get {
 261                                 if (selectArguments == null)
 262                                         selectArguments = CreateDataSourceSelectArguments ();
 263                                 return selectArguments;
 264                         }
 265                         private set {
 266                                 selectArguments = value;
 267                         }
 268                 }
 269
 270                 bool IsDataBound {
 271                         get {
 272                                 object dataBound = ViewState ["DataBound"];
 273                                 return dataBound != null ? (bool) dataBound : false;
 274                         }
 275                         set {
 276                                 ViewState ["DataBound"] = value;
 277                         }
 278                 }
 279
 280                 protected void MarkAsDataBound ()
 281                 {
 282                         IsDataBound = true;
 283                 }
 284         }
 285 }
 286
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