How to filter duplicate values from a grid ?

public DataTable SelectDistinct(DataTable SourceTable, string FieldName)
{
    // Create a Datatable  datatype same as FieldName
    DataTable dt = new DataTable(SourceTable.TableName);
    dt.Columns.Add(FieldName, SourceTable.Columns[FieldName].DataType);
    // Loop each row & compare each value with one another
    // Add it to datatable if the values are mismatch
    object LastValue = null;
    foreach (DataRow dr in SourceTable.Select("", FieldName))
    {
        if (LastValue == null || !(ColumnEqual(LastValue,dr[FieldName])))
        {
            LastValue = dr[FieldName];
           dt.Rows.Add(new object[] { LastValue });
        }
    }
    return dt;
}