Code:
/ Dotnetfx_Win7_3.5.1 / Dotnetfx_Win7_3.5.1 / 3.5.1 / DEVDIV / depot / DevDiv / releases / Orcas / NetFXw7 / ndp / fx / src / DataSet / System / Data / EnumerableRowCollection.cs / 1 / EnumerableRowCollection.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //[....] //----------------------------------------------------------------------------- using System; using System.Collections.Generic; using System.Collections; using System.Text; using System.Data; using System.Linq; using System.Diagnostics; using System.Linq.Expressions; using System.Collections.ObjectModel; using System.Data.DataSetExtensions; namespace System.Data { ////// Provides an entry point so that Cast operator call can be intercepted within an extension method. /// public abstract class EnumerableRowCollection : IEnumerable { internal abstract Type ElementType { get; } internal abstract DataTable Table { get; } internal EnumerableRowCollection() { } IEnumerator IEnumerable.GetEnumerator() { return null; } } ////// This class provides a wrapper for DataTables to allow for querying via LINQ. /// public class EnumerableRowCollection: EnumerableRowCollection, IEnumerable { private readonly DataTable _table; private readonly IEnumerable _enumerableRows; private readonly List > _listOfPredicates; // Stores list of sort expression in the order provided by user. E.g. order by, thenby, thenby descending.. private readonly SortExpressionBuilder _sortExpression; private readonly Func _selector; #region Properties internal override Type ElementType { get { return typeof(TRow); } } internal IEnumerable EnumerableRows { get { return _enumerableRows; } } internal override DataTable Table { get { return _table; } } #endregion Properties #region Constructors /// /// This constructor is used when Select operator is called with output Type other than input row Type. /// Basically fail on GetLDV(), but other LINQ operators must work. /// internal EnumerableRowCollection(IEnumerableenumerableRows, bool isDataViewable, DataTable table) { Debug.Assert(!isDataViewable || table != null, "isDataViewable bug table is null"); _enumerableRows = enumerableRows; if (isDataViewable) { _table = table; } _listOfPredicates = new List >(); _sortExpression = new SortExpressionBuilder (); } /// /// Basic Constructor /// internal EnumerableRowCollection(DataTable table) { _table = table; _enumerableRows = table.Rows.Cast(); _listOfPredicates = new List >(); _sortExpression = new SortExpressionBuilder (); } /// /// Copy Constructor that sets the input IEnumerable as enumerableRows /// Used to maintain IEnumerable that has linq operators executed in the same order as the user /// internal EnumerableRowCollection(EnumerableRowCollectionsource, IEnumerable enumerableRows, Func selector) { Debug.Assert(null != enumerableRows, "null enumerableRows"); _enumerableRows = enumerableRows; _selector = selector; if (null != source) { if (null == source._selector) { _table = source._table; } _listOfPredicates = new List >(source._listOfPredicates); _sortExpression = source._sortExpression.Clone(); //deep copy the List } else { _listOfPredicates = new List >(); _sortExpression = new SortExpressionBuilder (); } } #endregion Constructors #region PublicInterface IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } /// /// This method returns an strongly typed iterator /// for the underlying DataRow collection. /// ////// A strongly typed iterator. /// public IEnumeratorGetEnumerator() { return _enumerableRows.GetEnumerator(); } #endregion PublicInterface /// /// Evaluates filter and sort if necessary and returns /// a LinqDataView representing the LINQ query this class has collected. /// ///LinqDataView repesenting the LINQ query internal LinqDataView GetLinqDataView() //Called by AsLinqDataView { if ((null == _table) || !typeof(DataRow).IsAssignableFrom(typeof(TRow))) { throw DataSetUtil.NotSupported(Strings.ToLDVUnsupported); } LinqDataView view = null; #region BuildSinglePredicate FuncfinalPredicate = null; //Conjunction of all .Where(..) predicates if ((null != _selector) && (0 < _listOfPredicates.Count)) { // Hook up all individual predicates into one predicate // This delegate is a conjunction of multiple predicates set by the user // Note: This is a Short-Circuit Conjunction finalPredicate = delegate(DataRow row) { if (!Object.ReferenceEquals(row, _selector((TRow)(object)row))) { throw DataSetUtil.NotSupported(Strings.ToLDVUnsupported); } foreach (Func pred in _listOfPredicates) { if (!pred((TRow)(object)row)) { return false; } } return true; }; } else if (null != _selector) { finalPredicate = delegate(DataRow row) { if (!Object.ReferenceEquals(row, _selector((TRow)(object)row))) { throw DataSetUtil.NotSupported(Strings.ToLDVUnsupported); } return true; }; } else if (0 < _listOfPredicates.Count) { finalPredicate = delegate(DataRow row) { foreach (Func pred in _listOfPredicates) { if (!pred((TRow)(object)row)) { return false; } } return true; }; } #endregion BuildSinglePredicate #region Evaluate Filter/Sort // All of this mess below is because we want to create index only once. // // If we only have filter, we set _view.Predicate - 1 index creation // If we only have sort, we set _view.SortExpression() - 1 index creation // If we have BOTH, we set them through the constructor - 1 index creation // // Filter AND Sort if ((null != finalPredicate) && (0 < _sortExpression.Count)) { // A lot more work here because constructor does not know type K, // so the responsibility to create appropriate delegate comparers // is outside of the constructor. view = new LinqDataView( _table, finalPredicate, //Func() Predicate delegate(DataRow row) //System.Predicate { return finalPredicate(row); }, delegate(DataRow a, DataRow b) //Comparison for DV for Index creation { return _sortExpression.Compare( _sortExpression.Select((TRow)(object)a), _sortExpression.Select((TRow)(object)b) ); }, delegate(object key, DataRow row) //Comparison_K_T for DV's Find() { return _sortExpression.Compare( (List
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- ReadOnlyTernaryTree.cs
- LocatorPartList.cs
- SchemaImporterExtensionElementCollection.cs
- CodeMemberField.cs
- ButtonChrome.cs
- SqlServices.cs
- Line.cs
- SafeReadContext.cs
- XmlDataCollection.cs
- TextChangedEventArgs.cs
- NotificationContext.cs
- MenuItemCollection.cs
- XpsPackagingException.cs
- FullTextLine.cs
- ComponentDispatcherThread.cs
- BitmapCodecInfoInternal.cs
- ContainerControl.cs
- DefaultAutoFieldGenerator.cs
- FixedFlowMap.cs
- ActivityMarkupSerializationProvider.cs
- OleDbParameter.cs
- FontInfo.cs
- HijriCalendar.cs
- URLMembershipCondition.cs
- WeakRefEnumerator.cs
- EventTask.cs
- BaseDataBoundControl.cs
- ExtensionSimplifierMarkupObject.cs
- InstanceHandleReference.cs
- XmlDataSource.cs
- AssemblyContextControlItem.cs
- StrokeNodeOperations2.cs
- XamlRtfConverter.cs
- ExpressionDumper.cs
- CngKey.cs
- SizeAnimation.cs
- RuntimeIdentifierPropertyAttribute.cs
- UInt64Storage.cs
- PropertyDescriptorCollection.cs
- BuildProviderCollection.cs
- GenericUriParser.cs
- WindowsListView.cs
- TableColumn.cs
- RNGCryptoServiceProvider.cs
- ExpressionsCollectionEditor.cs
- DoWhileDesigner.xaml.cs
- OneOfConst.cs
- BaseCodeDomTreeGenerator.cs
- SchemaHelper.cs
- Stroke.cs
- ToolBarPanel.cs
- ManualResetEvent.cs
- TextRunTypographyProperties.cs
- FileDialogCustomPlacesCollection.cs
- ParseNumbers.cs
- QilInvoke.cs
- ButtonBaseAdapter.cs
- FunctionMappingTranslator.cs
- QuaternionConverter.cs
- RemotingConfigParser.cs
- basenumberconverter.cs
- PolyLineSegmentFigureLogic.cs
- TableLayoutPanelCodeDomSerializer.cs
- WebAdminConfigurationHelper.cs
- DataControlPagerLinkButton.cs
- WebRequest.cs
- SecurityUtils.cs
- Button.cs
- StaticFileHandler.cs
- GradientStop.cs
- CodeCompiler.cs
- Byte.cs
- Interlocked.cs
- OpCodes.cs
- XPathParser.cs
- OperationContext.cs
- LinkUtilities.cs
- GridViewUpdateEventArgs.cs
- InputBinding.cs
- XslCompiledTransform.cs
- ClickablePoint.cs
- RealProxy.cs
- QuaternionIndependentAnimationStorage.cs
- Lease.cs
- TemplateManager.cs
- WebPartEditorApplyVerb.cs
- QuadraticEase.cs
- SafeSerializationManager.cs
- AsymmetricSignatureFormatter.cs
- OperationResponse.cs
- FixedHyperLink.cs
- TextBox.cs
- SqlDataSourceCustomCommandEditor.cs
- precedingsibling.cs
- SyndicationDeserializer.cs
- Overlapped.cs
- OrderByExpression.cs
- DataGridCommandEventArgs.cs
- ActivityMarkupSerializer.cs
- SessionPageStatePersister.cs