compare datatable and return unmatched rows

To compare two DataTables and return the unmatched rows, you can use LINQ in C#. LINQ provides a powerful way to query data and perform set operations like finding the differences between two collections. Here's an example of how to compare two DataTables and return the rows that are present in one DataTable but not in the other:

Assuming you have two DataTables named table1 and table2, and both have the same schema (same columns):

csharpCopy code
using System;
using System.Data;
using System.Linq;

public class Program
{
    public static void Main()
    {
        // Sample DataTables
        DataTable table1 = GetSampleDataTable1();
        DataTable table2 = GetSampleDataTable2();

        // Compare DataTables and get unmatched rows from table1
        DataTable unmatchedRows = GetUnmatchedRows(table1, table2);

        // Print unmatched rows
        PrintDataTable(unmatchedRows);
    }

    // Sample DataTable 1
    private static DataTable GetSampleDataTable1()
    {
        DataTable table = new DataTable();
        table.Columns.Add("ID", typeof(int));
        table.Columns.Add("Name", typeof(string));

        table.Rows.Add(1, "John");
        table.Rows.Add(2, "Alice");
        table.Rows.Add(3, "Bob");

        return table;
    }

    // Sample DataTable 2
    private static DataTable GetSampleDataTable2()
    {
        DataTable table = new DataTable();
        table.Columns.Add("ID", typeof(int));
        table.Columns.Add("Name", typeof(string));

        table.Rows.Add(1, "John");
        table.Rows.Add(3, "Bob");
        table.Rows.Add(4, "Eve");

        return table;
    }

    // Compare DataTables and get unmatched rows from table1
    private static DataTable GetUnmatchedRows(DataTable table1, DataTable table2)
    {
        // LINQ query to get unmatched rows from table1
        var unmatchedRows = table1.AsEnumerable()
            .Where(row1 => !table2.AsEnumerable().Any(row2 =>
                row1.ItemArray.SequenceEqual(row2.ItemArray)))
            .CopyToDataTable();

        return unmatchedRows;
    }

    // Print DataTable
    private static void PrintDataTable(DataTable table)
    {
        foreach (DataRow row in table.Rows)
        {
            foreach (var item in row.ItemArray)
            {
                Console.Write(item + " ");
            }
            Console.WriteLine();
        }
    }
}

In this example, we have two sample DataTables table1 and table2. We compare them using LINQ's Any and SequenceEqual methods to find the unmatched rows in table1. The result is then stored in the unmatchedRows DataTable, which contains the rows that are present in table1 but not in table2. The PrintDataTable method is used to print the unmatched rows.