Compare two data tables for differences in C #?

You can use LINQ to combine two objects DataTablecorresponding to each column. Then grab IQueryableand find all the lines in the first two objects DataTablethat are not in IQueryable.

An example :

private void SampleSolution(DataTable dt1, DataTable dt2)
{
    //If you have primary keys:
    var results = from table1 in dt1.AsEnumerable()
                    join table2 in dt2.AsEnumerable() on table1.Field<int>("id") equals table2.Field<int>("id")
                    where table1.Field<int>("ColumnA") != table2.Field<int>("ColumnA") || table1.Field<int>("ColumnB") != table2.Field<int>("ColumnB") || table1.Field<String>("ColumnC") != table2.Field<String>("ColumnC")
                    select table1;
    //This will give you the rows in dt1 which do not match the rows in dt2.  You will need to expand the where clause to include all your columns.


    //If you do not have primarry keys then you will need to match up each column and then find the missing.
    var matched = from table1 in dt1.AsEnumerable()
                    join table2 in dt2.AsEnumerable() on table1.Field<int>("ColumnA") equals table2.Field<int>("ColumnA")
                    where table1.Field<int>("ColumnB") == table2.Field<int>("ColumnB") || table1.Field<string>("ColumnC") == table2.Field<string>("ColumnC") || table1.Field<object>("ColumnD") == table2.Field<object>("ColumnD")
                    select table1;
    var missing = from table1 in dt1.AsEnumerable()
                    where !matched.Contains(table1)
                    select table1;
    //This should give you the rows which do not have a match.  You will need to expand the where clause to include all your columns.
}

The code above should work, although I have not tested it.

LINQ DataTable, LINQ DataTables.
LINQ, LINQ.