Remove Duplicate entries from data table c#

by Ravi Tuvar 4:48 AM 0 comments

hi friends coming with new trick to remove the duplicate records from the datatable in csharp

private static void RemoveDuplicates(DataTable tbl, DataColumn[] keyColumns)

        {

            int rowNdx = 0;

            while (rowNdx < tbl.Rows.Count - 1)

            {

                DataRow[] dups = FindDups(tbl, rowNdx, keyColumns);

                if (dups.Length > 0)

                {

                    foreach (DataRow dup in dups)

                    {

                        tbl.Rows.Remove(dup);

                    }

                }

                else

                {

                    rowNdx++;

                }

            }

        }

private static DataRow[] FindDups(DataTable tbl,

                                             int sourceNdx,

                                             DataColumn[] keyColumns)

        {

            ArrayList retVal = new ArrayList();

            DataRow sourceRow = tbl.Rows[sourceNdx];

            for (int i = sourceNdx + 1; i < tbl.Rows.Count; i++)

            {

                DataRow targetRow = tbl.Rows[i];

                if (IsDup(sourceRow, targetRow, keyColumns))

                {

                    retVal.Add(targetRow);

                }

            }

            return (DataRow[])retVal.ToArray(typeof(DataRow));

        }

private static bool IsDup(DataRow sourceRow,

                                  DataRow targetRow,

                                  DataColumn[] keyColumns)

        {

            bool retVal = true;

            foreach (DataColumn column in keyColumns)

            {

                retVal = retVal && sourceRow[column].Equals(targetRow[column]);

                if (!retVal) break;

            }

            return retVal;

        }

 

 

 

Now pass the datatable and key columns in RemoveDuplicates as below:

DataColumn[] keyColumns =

                                  new DataColumn[]{dt.Columns["VisitorId"],

                                               dt.Columns["Name"],dt.Columns["FaceId"]};

                    RemoveDuplicates(dt, keyColumns);