//******************************************************************************************************//  DataSetEqualityComparer.cs - Gbtc////  Copyright © 2013, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  08/09/2013 - Stephen C. Wills//       Generated original version of source code.////****************************************************************************************************** using System;using System.Collections.Generic;using System.Data;using System.Diagnostics.CodeAnalysis; namespace GSF.Data{    /// <summary>    /// Equality comparer for <see cref="T:System.Data.DataSet"/> objects.    /// </summary>    public class DataSetEqualityComparer : IEqualityComparer<DataSet>    {        private DataSetEqualityComparer()        {        }         /// <summary>        /// Determines whether the specified objects are equal.        /// </summary>        /// <returns>        /// true if the specified objects are equal; otherwise, false.        /// </returns>        /// <param name="x">The first object of type <see cref="T:System.Data.DataSet"/> to compare.</param>        /// <param name="y">The second object of type <see cref="T:System.Data.DataSet"/> to compare.</param>        public bool Equals(DataSet x, DataSet y)        {            // If the two data sets are the same object, they are equal            if (ReferenceEquals(x, y))                return true;             // Test for null            if (x is null || y is null)                return false;             // Check that the number of tables match            if (x.Tables.Count != y.Tables.Count)                return false;             foreach (DataTable xTable in x.Tables)            {                // Check that both data sets have this table defined                if (!y.Tables.Contains(xTable.TableName))                    return false;                 DataTable yTable = y.Tables[xTable.TableName];                 // Check that both tables have the same number of rows                if (xTable.Rows.Count != yTable.Rows.Count)                    return false;                 // Check that both tables have the same number of columns                if (xTable.Columns.Count != yTable.Columns.Count)                    return false;                 for (int i = 0; i < xTable.Rows.Count; i++)                {                    foreach (DataColumn column in xTable.Columns)                    {                        // Check that both tables contain this particular column                        if (!yTable.Columns.Contains(column.ColumnName))                            return false;                         object xField = xTable.Rows[i][column.ColumnName];                        object yField = yTable.Rows[i][column.ColumnName];                         if (xField == DBNull.Value || yField == DBNull.Value)                        {                            // At least one value is DBNull,                            // so this checks if they are both DBNull                            if (xField != yField)                                return false;                        }                        else if (!xField.Equals(yField))                        {                            // The values are not equal                            return false;                        }                    }                }            }             return true;        }         /// <summary>        /// Returns a hash code for the specified object.        /// </summary>        /// <returns>        /// A hash code for the specified object.        /// </returns>        /// <param name="obj">The <see cref="T:System.Data.DataSet"/> for which a hash code is to be returned.</param>        /// <exception cref="T:System.ArgumentNullException">The type of <paramref name="obj"/> is a reference type and <paramref name="obj"/> is null.</exception>        public int GetHashCode(DataSet obj)        {            int hashCode = 0;             if (obj is null)                throw new ArgumentNullException(nameof(obj));             // This method is required by IEqualityComparer<T> - although the following             // should work, this is not likely the most efficient way to do this...            foreach (DataTable table in obj.Tables)            {                foreach (DataRow row in table.Rows)                {                    foreach (DataColumn column in table.Columns)                    {                        object field = row[column];                         if (field is null)                            continue;                                                hashCode ^= field.GetHashCode();                    }                }            }             return hashCode;        }         /// <summary>        /// Default instance of the <see cref="DataSetEqualityComparer"/> class.        /// </summary>        [SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]        public static readonly DataSetEqualityComparer Default = new DataSetEqualityComparer();    }}