Code:
/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / ndp / fx / src / DataSet / System / Data / DataRowComparer.cs / 1 / DataRowComparer.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //spather //----------------------------------------------------------------------------- using System; using System.Data; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Data.DataSetExtensions; namespace System.Data { ////// This class implements IEqualityComparer using value based semantics /// when comparing DataRows. /// public static class DataRowComparer { ////// Gets the singleton instance of the data row comparer. /// public static DataRowComparerDefault { get { return DataRowComparer .Default; } } internal static bool AreEqual(object a, object b) { if (Object.ReferenceEquals(a, b)) { // same reference or (null, null) or (DBNull.Value, DBNull.Value) return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(a, DBNull.Value) || Object.ReferenceEquals(b, null) || Object.ReferenceEquals(b, DBNull.Value)) { // (null, non-null) or (null, DBNull.Value) or vice versa return false; } return (a.Equals(b) || (a.GetType().IsArray && CompareArray((Array)a, b as Array))); } private static bool AreElementEqual(object a, object b) { if (Object.ReferenceEquals(a, b)) { // same reference or (null, null) or (DBNull.Value, DBNull.Value) return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(a, DBNull.Value) || Object.ReferenceEquals(b, null) || Object.ReferenceEquals(b, DBNull.Value)) { // (null, non-null) or (null, DBNull.Value) or vice versa return false; } return a.Equals(b); } private static bool CompareArray(Array a, Array b) { if ((null == b) || (1 != a.Rank) || (1 != b.Rank) || (a.Length != b.Length)) { // automatically consider array's with Rank>1 not-equal return false; } int index1 = a.GetLowerBound(0); int index2 = b.GetLowerBound(0); if (a.GetType() == b.GetType() && (0 == index1) && (0 == index2)) { switch (Type.GetTypeCode(a.GetType().GetElementType())) { case TypeCode.Byte: return DataRowComparer.CompareEquatableArray ((Byte[])a, (Byte[])b); case TypeCode.Int16: return DataRowComparer.CompareEquatableArray ((Int16[])a, (Int16[])b); case TypeCode.Int32: return DataRowComparer.CompareEquatableArray ((Int32[])a, (Int32[])b); case TypeCode.Int64: return DataRowComparer.CompareEquatableArray ((Int64[])a, (Int64[])b); case TypeCode.String: return DataRowComparer.CompareEquatableArray ((String[])a, (String[])b); } } //Compare every element. But don't recurse if we have Array of array. int length = index1 + a.Length; for (; index1 < length; ++index1, ++index2) { if (!AreElementEqual(a.GetValue(index1), b.GetValue(index2))) { return false; } } return true; } private static bool CompareEquatableArray (TElem[] a, TElem[] b) where TElem : IEquatable { if (Object.ReferenceEquals(a, b)) { return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(b, null)) { return false; } if (a.Length != b.Length) { return false; } for (int i = 0; i < a.Length; ++i) { if (!a[i].Equals(b[i])) { return false; } } return true; } } /// /// This class implements IEqualityComparer using value based semantics /// when comparing DataRows. /// public sealed class DataRowComparer: IEqualityComparer where TRow : DataRow { /// /// Private constructor to prevent initialization outside of Default singleton instance. /// private DataRowComparer() { } private static DataRowComparer_instance = new DataRowComparer (); /// /// Gets the singleton instance of the data row comparer. /// public static DataRowComparerDefault { get { return _instance; } } /// /// This method compares to DataRows by doing a column by column value based /// comparision. /// /// /// The first input DataRow /// /// /// The second input DataRow /// ////// True if rows are equal, false if not. /// public bool Equals(TRow leftRow, TRow rightRow) { if (Object.ReferenceEquals(leftRow, rightRow)) { return true; } if (Object.ReferenceEquals(leftRow, null) || Object.ReferenceEquals(rightRow, null)) { return false; } if (leftRow.RowState == DataRowState.Deleted || rightRow.RowState == DataRowState.Deleted) { throw DataSetUtil.InvalidOperation(Strings.DataSetLinq_CannotCompareDeletedRow); } int count = leftRow.Table.Columns.Count; if (count != rightRow.Table.Columns.Count) { return false; } for (int i = 0; i < count; ++i) { if (!DataRowComparer.AreEqual(leftRow[i], rightRow[i])) { return false; } } return true; } ////// This mtheod retrieves a hash code for the source row. /// /// /// The source DataRow /// ////// HashCode for row based on values in the row. /// public int GetHashCode(TRow row) { DataSetUtil.CheckArgumentNull(row, "row"); if (row.RowState == DataRowState.Deleted) { throw DataSetUtil.InvalidOperation(Strings.DataSetLinq_CannotCompareDeletedRow); } int hash = 0; Debug.Assert(row.Table != null); if (row.Table.Columns.Count > 0) { // if the row has at least one column, then use the first column value object value = row[0]; Type valueType = value.GetType(); if (valueType.IsArray) { Array array = value as Array; if (array.Rank > 1) { hash = value.GetHashCode(); } else if (array.Length > 0) { hash = array.GetValue(array.GetLowerBound(0)).GetHashCode(); } } else { System.ValueType vt = value as System.ValueType; // have to unbox value types. if (vt != null) { hash = vt.GetHashCode(); } else { hash = value.GetHashCode(); } } } // if table has no columns, the hash code is 0 return hash; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. //------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //[....] //spather //----------------------------------------------------------------------------- using System; using System.Data; using System.Collections; using System.Collections.Generic; using System.Diagnostics; using System.Data.DataSetExtensions; namespace System.Data { ////// This class implements IEqualityComparer using value based semantics /// when comparing DataRows. /// public static class DataRowComparer { ////// Gets the singleton instance of the data row comparer. /// public static DataRowComparerDefault { get { return DataRowComparer .Default; } } internal static bool AreEqual(object a, object b) { if (Object.ReferenceEquals(a, b)) { // same reference or (null, null) or (DBNull.Value, DBNull.Value) return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(a, DBNull.Value) || Object.ReferenceEquals(b, null) || Object.ReferenceEquals(b, DBNull.Value)) { // (null, non-null) or (null, DBNull.Value) or vice versa return false; } return (a.Equals(b) || (a.GetType().IsArray && CompareArray((Array)a, b as Array))); } private static bool AreElementEqual(object a, object b) { if (Object.ReferenceEquals(a, b)) { // same reference or (null, null) or (DBNull.Value, DBNull.Value) return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(a, DBNull.Value) || Object.ReferenceEquals(b, null) || Object.ReferenceEquals(b, DBNull.Value)) { // (null, non-null) or (null, DBNull.Value) or vice versa return false; } return a.Equals(b); } private static bool CompareArray(Array a, Array b) { if ((null == b) || (1 != a.Rank) || (1 != b.Rank) || (a.Length != b.Length)) { // automatically consider array's with Rank>1 not-equal return false; } int index1 = a.GetLowerBound(0); int index2 = b.GetLowerBound(0); if (a.GetType() == b.GetType() && (0 == index1) && (0 == index2)) { switch (Type.GetTypeCode(a.GetType().GetElementType())) { case TypeCode.Byte: return DataRowComparer.CompareEquatableArray ((Byte[])a, (Byte[])b); case TypeCode.Int16: return DataRowComparer.CompareEquatableArray ((Int16[])a, (Int16[])b); case TypeCode.Int32: return DataRowComparer.CompareEquatableArray ((Int32[])a, (Int32[])b); case TypeCode.Int64: return DataRowComparer.CompareEquatableArray ((Int64[])a, (Int64[])b); case TypeCode.String: return DataRowComparer.CompareEquatableArray ((String[])a, (String[])b); } } //Compare every element. But don't recurse if we have Array of array. int length = index1 + a.Length; for (; index1 < length; ++index1, ++index2) { if (!AreElementEqual(a.GetValue(index1), b.GetValue(index2))) { return false; } } return true; } private static bool CompareEquatableArray (TElem[] a, TElem[] b) where TElem : IEquatable { if (Object.ReferenceEquals(a, b)) { return true; } if (Object.ReferenceEquals(a, null) || Object.ReferenceEquals(b, null)) { return false; } if (a.Length != b.Length) { return false; } for (int i = 0; i < a.Length; ++i) { if (!a[i].Equals(b[i])) { return false; } } return true; } } /// /// This class implements IEqualityComparer using value based semantics /// when comparing DataRows. /// public sealed class DataRowComparer: IEqualityComparer where TRow : DataRow { /// /// Private constructor to prevent initialization outside of Default singleton instance. /// private DataRowComparer() { } private static DataRowComparer_instance = new DataRowComparer (); /// /// Gets the singleton instance of the data row comparer. /// public static DataRowComparerDefault { get { return _instance; } } /// /// This method compares to DataRows by doing a column by column value based /// comparision. /// /// /// The first input DataRow /// /// /// The second input DataRow /// ////// True if rows are equal, false if not. /// public bool Equals(TRow leftRow, TRow rightRow) { if (Object.ReferenceEquals(leftRow, rightRow)) { return true; } if (Object.ReferenceEquals(leftRow, null) || Object.ReferenceEquals(rightRow, null)) { return false; } if (leftRow.RowState == DataRowState.Deleted || rightRow.RowState == DataRowState.Deleted) { throw DataSetUtil.InvalidOperation(Strings.DataSetLinq_CannotCompareDeletedRow); } int count = leftRow.Table.Columns.Count; if (count != rightRow.Table.Columns.Count) { return false; } for (int i = 0; i < count; ++i) { if (!DataRowComparer.AreEqual(leftRow[i], rightRow[i])) { return false; } } return true; } ////// This mtheod retrieves a hash code for the source row. /// /// /// The source DataRow /// ////// HashCode for row based on values in the row. /// public int GetHashCode(TRow row) { DataSetUtil.CheckArgumentNull(row, "row"); if (row.RowState == DataRowState.Deleted) { throw DataSetUtil.InvalidOperation(Strings.DataSetLinq_CannotCompareDeletedRow); } int hash = 0; Debug.Assert(row.Table != null); if (row.Table.Columns.Count > 0) { // if the row has at least one column, then use the first column value object value = row[0]; Type valueType = value.GetType(); if (valueType.IsArray) { Array array = value as Array; if (array.Rank > 1) { hash = value.GetHashCode(); } else if (array.Length > 0) { hash = array.GetValue(array.GetLowerBound(0)).GetHashCode(); } } else { System.ValueType vt = value as System.ValueType; // have to unbox value types. if (vt != null) { hash = vt.GetHashCode(); } else { hash = value.GetHashCode(); } } } // if table has no columns, the hash code is 0 return hash; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- HandleCollector.cs
- DBSqlParserTable.cs
- BufferedGraphics.cs
- IBuiltInEvidence.cs
- TreeNodeConverter.cs
- XamlValidatingReader.cs
- IndentTextWriter.cs
- XmlSchemaDatatype.cs
- XpsS0ValidatingLoader.cs
- PageAsyncTaskManager.cs
- TextTreeDeleteContentUndoUnit.cs
- PageEventArgs.cs
- ExpressionNode.cs
- BinaryMethodMessage.cs
- QfeChecker.cs
- HotSpotCollectionEditor.cs
- MatrixTransform3D.cs
- SystemFonts.cs
- ToolStripLocationCancelEventArgs.cs
- TextServicesHost.cs
- ToggleButton.cs
- CallContext.cs
- ProjectionCamera.cs
- FilteredAttributeCollection.cs
- DictionaryKeyPropertyAttribute.cs
- ByteConverter.cs
- EventMappingSettingsCollection.cs
- Pen.cs
- Perspective.cs
- DeclarationUpdate.cs
- XmlEncodedRawTextWriter.cs
- ListViewContainer.cs
- sitestring.cs
- RealizationDrawingContextWalker.cs
- Subtree.cs
- ListViewUpdatedEventArgs.cs
- PointConverter.cs
- ConfigXmlElement.cs
- WebBrowserBase.cs
- NamedPipeTransportElement.cs
- SqlGenerator.cs
- SeverityFilter.cs
- SqlTopReducer.cs
- HostedImpersonationContext.cs
- CompilerScope.Storage.cs
- SchemaType.cs
- DataGridColumnCollectionEditor.cs
- DataGridViewHitTestInfo.cs
- RemotingServices.cs
- IPPacketInformation.cs
- LazyTextWriterCreator.cs
- AnimationLayer.cs
- PackagePartCollection.cs
- RegisteredExpandoAttribute.cs
- ReadOnlyKeyedCollection.cs
- UserNamePasswordServiceCredential.cs
- DbResourceAllocator.cs
- AdapterUtil.cs
- DataGridViewHitTestInfo.cs
- XmlSchemas.cs
- XPathAncestorQuery.cs
- StreamResourceInfo.cs
- ThicknessAnimationBase.cs
- BindingOperations.cs
- DiscriminatorMap.cs
- WinInetCache.cs
- PasswordRecovery.cs
- Point4DValueSerializer.cs
- Pkcs7Signer.cs
- PeerName.cs
- CodeTypeDelegate.cs
- ContentElement.cs
- Keyboard.cs
- AuthenticationModuleElement.cs
- FixedDocumentPaginator.cs
- DataGridRelationshipRow.cs
- UshortList2.cs
- StatusBarDrawItemEvent.cs
- OpenFileDialog.cs
- IssuedTokenServiceElement.cs
- EventRouteFactory.cs
- MULTI_QI.cs
- RequestSecurityToken.cs
- Vector.cs
- XmlSchemaAnnotated.cs
- MetaType.cs
- TextEditorTables.cs
- CDSsyncETWBCLProvider.cs
- ErrorInfoXmlDocument.cs
- translator.cs
- TextEndOfLine.cs
- ExpressionNormalizer.cs
- StatementContext.cs
- ProfileParameter.cs
- FontEditor.cs
- CngProvider.cs
- HostnameComparisonMode.cs
- Binding.cs
- Point4D.cs
- DataGridViewAddColumnDialog.cs