What can be most efficient way of filtering data in DataTable?

Question

The performance is not good, taking so much time. How can I improve the performance of the following code that gives me the same result? for (int i = 0; i { DataTable dtFiltered = dtWorkExp.Clone(); foreach (DataRow drr in dtWorkExp.Rows) { if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString()) { dtFiltered.ImportRow(drr); } } DataTable dtFilteredAward= dtAwards.Clone(); foreach (DataRow drr in dtAwards.Rows) { if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString()) { dtFilteredAward.ImportRow(drr); } } DataTable dtFilteredOtherQual = dtOtherQual.Clone(); foreach (DataRow drr in dtOtherQual.Rows) { if (drr["UserId"].ToString() == dsResult.Tables[0].Rows[l]["Registration NO."].ToString()) { dtFilteredOtherQual.ImportRow(drr); } } //Do some operation with filtered Data Tables }

Pankaj Patel · Answer

Hi Zulqadar Idrishi, One of the most efficient way of filtering data in DataTable is with using LINQ to Inner join of DataTables in C# as like following: var dtFilteredWorkExpNew = from table1 in dtResult.AsEnumerable() join table2 in dtWorkExp.AsEnumerable() on ( int )table1[ "RegistrationNO" ] equals ( int )table2[ "UserId" ] select new { UserId = (Int32)table2[ "UserId" ], Exp = ( string )table2[ "Exp" ] }; foreach (var item in dtFilteredWorkExpNew) { Console.WriteLine(String.Format( "UserId = {0}, Exp = {1}" , item.UserId, item.Exp)); } Here, with this reply I have also attached sample example with output. For more details: https://stackoverflow.com/questions/665754/inner-join-of-datatables-in-c-sharp Hope, this will help you!