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
- CompilerTypeWithParams.cs
- Int32.cs
- SafeNativeMethodsMilCoreApi.cs
- HttpCapabilitiesSectionHandler.cs
- DPTypeDescriptorContext.cs
- ElementNotEnabledException.cs
- TemplateFactory.cs
- StorageInfo.cs
- ResourcePool.cs
- EditorBrowsableAttribute.cs
- ErrorInfoXmlDocument.cs
- BStrWrapper.cs
- ApplicationFileCodeDomTreeGenerator.cs
- Int16AnimationBase.cs
- CustomValidator.cs
- ProfileBuildProvider.cs
- ControlPropertyNameConverter.cs
- XmlSchemaIdentityConstraint.cs
- ControlLocalizer.cs
- DayRenderEvent.cs
- SessionIDManager.cs
- WinInetCache.cs
- TextBoxRenderer.cs
- WorkflowPersistenceService.cs
- KeyProperty.cs
- AsyncOperation.cs
- ZipIOZip64EndOfCentralDirectoryBlock.cs
- SctClaimSerializer.cs
- StorageComplexPropertyMapping.cs
- DataGridViewAutoSizeModeEventArgs.cs
- Peer.cs
- AppSecurityManager.cs
- RouteParametersHelper.cs
- OAVariantLib.cs
- CompilerScope.Storage.cs
- CodeSnippetCompileUnit.cs
- TypeSource.cs
- BindingCompleteEventArgs.cs
- XmlSiteMapProvider.cs
- Subset.cs
- PrinterResolution.cs
- Stylesheet.cs
- DocumentReferenceCollection.cs
- linebase.cs
- KeyToListMap.cs
- ComponentSerializationService.cs
- ConfigurationSectionCollection.cs
- SecurityKeyIdentifier.cs
- XmlTextWriter.cs
- RequestQueue.cs
- _Rfc2616CacheValidators.cs
- BamlLocalizerErrorNotifyEventArgs.cs
- HttpListenerRequestUriBuilder.cs
- InheritanceUI.cs
- PersonalizationProvider.cs
- AssemblyResourceLoader.cs
- CodeTypeParameterCollection.cs
- ComboBoxRenderer.cs
- BitStream.cs
- TableLayoutColumnStyleCollection.cs
- DataReceivedEventArgs.cs
- SystemTcpConnection.cs
- SqlFunctionAttribute.cs
- ConfigurationManagerHelperFactory.cs
- OptimalTextSource.cs
- ConfigurationValidatorBase.cs
- _BasicClient.cs
- EntityParameterCollection.cs
- ObjectConverter.cs
- AppSettings.cs
- TargetPerspective.cs
- DataGridViewColumnCollection.cs
- MaskedTextBox.cs
- ServiceX509SecurityTokenProvider.cs
- Table.cs
- GuidConverter.cs
- AnonymousIdentificationModule.cs
- Triplet.cs
- Ref.cs
- BulletChrome.cs
- SqlDataSourceSelectingEventArgs.cs
- ResXFileRef.cs
- _DisconnectOverlappedAsyncResult.cs
- ClaimTypeElement.cs
- FunctionImportMapping.cs
- DynamicActivityXamlReader.cs
- ReferencedCollectionType.cs
- Tablet.cs
- CommonDialog.cs
- TagPrefixCollection.cs
- WindowsPrincipal.cs
- UdpMessageProperty.cs
- WebPartHeaderCloseVerb.cs
- ProgressBarRenderer.cs
- WebPartAddingEventArgs.cs
- OleDbConnectionPoolGroupProviderInfo.cs
- FaultImportOptions.cs
- Drawing.cs
- VirtualPathUtility.cs
- SetterBase.cs