305 lines
8.8 KiB
C#
305 lines
8.8 KiB
C#
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//
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// ColumnReference.cs
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//
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// Author:
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// Juraj Skripsky (juraj@hotfeet.ch)
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//
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// (C) 2004 HotFeet GmbH (http://www.hotfeet.ch)
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//
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//
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// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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using System;
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using System.Collections;
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using System.Data;
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using System.ComponentModel;
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namespace Mono.Data.SqlExpressions {
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internal enum ReferencedTable {
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Self,
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Parent,
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Child
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}
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internal class ColumnReference : BaseExpression {
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ReferencedTable refTable;
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string relationName, columnName;
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DataColumn _cachedColumn;
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DataRelation _cachedRelation;
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public ColumnReference (string columnName) : this (ReferencedTable.Self, null, columnName) {}
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public ColumnReference (ReferencedTable refTable, string relationName, string columnName)
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{
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this.refTable = refTable;
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this.relationName = relationName;
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this.columnName = columnName;
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}
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public override bool Equals(object obj)
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{
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if (!base.Equals (obj))
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return false;
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if (!(obj is ColumnReference))
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return false;
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ColumnReference other = (ColumnReference) obj;
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if (other.refTable != refTable)
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return false;
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if (other.columnName != columnName)
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return false;
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if (other.relationName != relationName)
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return false;
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return true;
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}
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public override int GetHashCode()
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{
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int hashCode = base.GetHashCode ();
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hashCode ^= refTable.GetHashCode ();
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hashCode ^= columnName.GetHashCode ();
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hashCode ^= relationName.GetHashCode ();
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return hashCode;
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}
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public ReferencedTable ReferencedTable {
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get { return refTable; }
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}
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private DataRelation GetRelation (DataRow row)
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{
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if (_cachedRelation == null) {
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DataTable table = row.Table;
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DataRelationCollection relations;
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if (relationName != null) {
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relations = table.DataSet.Relations;
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_cachedRelation = relations [relations.IndexOf (relationName)];
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}
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else {
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if (refTable == ReferencedTable.Parent)
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relations = table.ParentRelations;
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else
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relations = table.ChildRelations;
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if (relations.Count > 1)
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throw new EvaluateException (String.Format (
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"The table [{0}] is involved in more than one relation." +
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"You must explicitly mention a relation name.",
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table.TableName));
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else
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_cachedRelation = relations [0];
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}
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_cachedRelation.DataSet.Relations.CollectionChanged += new CollectionChangeEventHandler (OnRelationRemoved);
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}
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return _cachedRelation;
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}
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private DataColumn GetColumn (DataRow row)
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{
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if (_cachedColumn == null) {
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DataTable table = row.Table;
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switch (refTable) {
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case ReferencedTable.Parent:
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table = GetRelation (row).ParentTable;
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break;
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case ReferencedTable.Child:
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table = GetRelation (row).ChildTable;
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break;
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}
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_cachedColumn = table.Columns [columnName];
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if (_cachedColumn == null)
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throw new EvaluateException (String.Format ("Cannot find column [{0}].", columnName));
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_cachedColumn.PropertyChanged += new PropertyChangedEventHandler (OnColumnPropertyChanged);
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_cachedColumn.Table.Columns.CollectionChanged += new CollectionChangeEventHandler (OnColumnRemoved);
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}
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return _cachedColumn;
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}
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public DataRow GetReferencedRow (DataRow row)
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{
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// Verify the column reference is valid
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GetColumn (row);
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switch (refTable) {
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case ReferencedTable.Self:
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default:
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return row;
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case ReferencedTable.Parent:
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return row.GetParentRow (GetRelation (row));
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case ReferencedTable.Child:
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return row.GetChildRows (GetRelation (row)) [0];
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}
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}
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public DataRow[] GetReferencedRows (DataRow row)
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{
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// Verify the column reference is valid
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GetColumn (row);
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switch (refTable) {
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case ReferencedTable.Self:
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default:
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DataRow[] rows = row.Table.NewRowArray(row.Table.Rows.Count);
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row.Table.Rows.CopyTo (rows, 0);
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return rows;
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case ReferencedTable.Parent:
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return row.GetParentRows (GetRelation (row));
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case ReferencedTable.Child:
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return row.GetChildRows (GetRelation (row));
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}
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}
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public object[] GetValues (DataRow[] rows)
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{
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object[] values = new object [rows.Length];
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for (int i = 0; i < rows.Length; i++)
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values [i] = Unify (rows [i][GetColumn (rows [i])]);
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return values;
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}
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private object Unify (object val) {
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if (Numeric.IsNumeric (val))
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return Numeric.Unify ((IConvertible)val);
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if (val == null || val == DBNull.Value)
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return null;
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if (val is bool || val is string || val is DateTime || val is Guid || val is char)
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return val;
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if (val is Enum)
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return (int)val;
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throw new EvaluateException (String.Format ("Cannot handle data type found in column '{0}'.", columnName));
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}
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public override object Eval (DataRow row)
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{
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DataRow referencedRow = GetReferencedRow (row);
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if (referencedRow == null)
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return null;
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object val;
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try {
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referencedRow._inExpressionEvaluation = true;
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val = referencedRow [GetColumn (row)];
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referencedRow._inExpressionEvaluation = false;
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} catch (IndexOutOfRangeException) {
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throw new EvaluateException (String.Format ("Cannot find column [{0}].", columnName));
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}
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return Unify (val);
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}
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public override bool EvalBoolean (DataRow row)
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{
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DataColumn col = GetColumn (row);
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if (col.DataType != typeof (bool))
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throw new EvaluateException ("Not a Boolean Expression");
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object result = Eval (row);
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if (result == null || result == DBNull.Value)
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return false;
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else
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return (bool)result;
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}
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override public bool DependsOn(DataColumn other)
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{
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return refTable == ReferencedTable.Self && columnName == other.ColumnName;
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}
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private void DropCached (DataColumnCollection columnCollection, DataRelationCollection relationCollection)
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{
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if (_cachedColumn != null) {
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// unregister column listener
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_cachedColumn.PropertyChanged -= new PropertyChangedEventHandler (OnColumnPropertyChanged);
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// unregister column collection listener
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if (columnCollection != null)
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columnCollection.CollectionChanged -= new CollectionChangeEventHandler (OnColumnRemoved);
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else if (_cachedColumn.Table != null)
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_cachedColumn.Table.Columns.CollectionChanged -= new CollectionChangeEventHandler (OnColumnRemoved);
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_cachedColumn = null;
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}
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if (_cachedRelation != null) {
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// unregister relation collection listener
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if (relationCollection != null)
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relationCollection.CollectionChanged -= new CollectionChangeEventHandler (OnRelationRemoved);
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else if (_cachedRelation.DataSet != null)
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_cachedRelation.DataSet.Relations.CollectionChanged -= new CollectionChangeEventHandler (OnRelationRemoved);
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_cachedRelation = null;
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}
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}
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private void OnColumnPropertyChanged (object sender, PropertyChangedEventArgs args)
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{
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if (!(sender is DataColumn))
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return;
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DataColumn dc = (DataColumn) sender;
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if ((dc == _cachedColumn) && args.PropertyName == "ColumnName")
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DropCached (null, null);
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}
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private void OnColumnRemoved (object sender, CollectionChangeEventArgs args)
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{
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if (!(args.Element is DataColumnCollection))
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return;
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if (args.Action != CollectionChangeAction.Remove)
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return;
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DataColumnCollection columnCollection = (DataColumnCollection) args.Element;
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if (_cachedColumn != null && columnCollection != null && (columnCollection.IndexOf (_cachedColumn)) == -1)
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DropCached (columnCollection, null);
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}
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private void OnRelationRemoved (object sender, CollectionChangeEventArgs args)
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{
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if (!(args.Element is DataRelationCollection))
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return;
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if (args.Action != CollectionChangeAction.Remove)
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return;
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DataRelationCollection relationCollection = (DataRelationCollection) args.Element;
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if (_cachedRelation != null && relationCollection != null && (relationCollection.IndexOf (_cachedRelation)) == -1)
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DropCached (null, relationCollection);
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}
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}
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}
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