Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / 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
- CTreeGenerator.cs
- Debug.cs
- GridViewRowCollection.cs
- XmlSchemaSimpleTypeRestriction.cs
- Identity.cs
- XmlValueConverter.cs
- WhitespaceSignificantCollectionAttribute.cs
- unitconverter.cs
- Matrix.cs
- TargetControlTypeCache.cs
- DataServiceRequestException.cs
- ProvidePropertyAttribute.cs
- SafeRightsManagementHandle.cs
- MenuItem.cs
- PageThemeCodeDomTreeGenerator.cs
- OdbcErrorCollection.cs
- CodeTypeConstructor.cs
- SafeRightsManagementEnvironmentHandle.cs
- MatrixAnimationBase.cs
- FileSecurity.cs
- SortDescription.cs
- Helper.cs
- ComponentGlyph.cs
- UnsafeNativeMethods.cs
- RtfFormatStack.cs
- QilUnary.cs
- GrammarBuilderRuleRef.cs
- XmlSchemaAny.cs
- CompileLiteralTextParser.cs
- WindowsListViewItemStartMenu.cs
- DetailsViewUpdatedEventArgs.cs
- TransactionException.cs
- DefaultProxySection.cs
- TraceSource.cs
- StringPropertyBuilder.cs
- StylusShape.cs
- ValueUnavailableException.cs
- LoginStatusDesigner.cs
- Normalization.cs
- Ops.cs
- PathParser.cs
- BindingEntityInfo.cs
- AttributeExtensions.cs
- WebBrowserHelper.cs
- DataGridItemEventArgs.cs
- Literal.cs
- AbstractSvcMapFileLoader.cs
- OutputBuffer.cs
- CommittableTransaction.cs
- FontInfo.cs
- Timeline.cs
- MultipleViewPattern.cs
- TextFindEngine.cs
- PropertyEntry.cs
- FrameworkReadOnlyPropertyMetadata.cs
- RichTextBox.cs
- LOSFormatter.cs
- ProviderConnectionPoint.cs
- DataServiceRequestOfT.cs
- ExpressionStringBuilder.cs
- CharAnimationUsingKeyFrames.cs
- NavigationWindowAutomationPeer.cs
- SequentialActivityDesigner.cs
- ToolStripRenderEventArgs.cs
- ScrollProviderWrapper.cs
- CreateParams.cs
- SystemIPv4InterfaceProperties.cs
- NavigationPropertyEmitter.cs
- WindowsGraphicsWrapper.cs
- sqlser.cs
- ViewManagerAttribute.cs
- ErrorHandler.cs
- StrokeNodeOperations.cs
- RenderTargetBitmap.cs
- CustomLineCap.cs
- MachineKeySection.cs
- ContainerTracking.cs
- ResourceManager.cs
- _UriSyntax.cs
- ValidatorCompatibilityHelper.cs
- LinkLabel.cs
- HttpServerUtilityBase.cs
- XmlSecureResolver.cs
- ConfigXmlText.cs
- HtmlFormAdapter.cs
- SchemaRegistration.cs
- SafeBitVector32.cs
- InkPresenter.cs
- StrongNameIdentityPermission.cs
- HtmlInputReset.cs
- PluralizationServiceUtil.cs
- CacheOutputQuery.cs
- HttpModuleAction.cs
- MasterPageParser.cs
- NeedSkipTokenVisitor.cs
- StateManagedCollection.cs
- CommentGlyph.cs
- AppSettingsReader.cs
- Attributes.cs
- CodeBinaryOperatorExpression.cs