datatable create On fly and datatable Fill data by funcation

  private DataTable CreateDataTable()
        {//---Create datatable with datatype
            DataTable myDataTable = new DataTable();

            DataColumn myDataColumn;
            ///id//Specification/SpId/SelectBK/QtyGWt/Unit//TotalLess/Netwt
            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.Int32");
            myDataColumn.ColumnName = "id";
            myDataTable.Columns.Add(myDataColumn);


            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.String");
            myDataColumn.ColumnName = "Specification";
            myDataTable.Columns.Add(myDataColumn);

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.String");
            myDataColumn.ColumnName = "SpId";
            myDataTable.Columns.Add(myDataColumn);

         

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.String");
            myDataColumn.ColumnName = "SelectBK";
            myDataTable.Columns.Add(myDataColumn);

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.Double");
            myDataColumn.ColumnName = "QtyGWt";
            myDataTable.Columns.Add(myDataColumn);

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.String");
            myDataColumn.ColumnName = "Unit";
            myDataTable.Columns.Add(myDataColumn);


            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.Double");
            myDataColumn.ColumnName = "TotalLess";
            myDataTable.Columns.Add(myDataColumn);

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.Double");
            myDataColumn.ColumnName = "Netwt";
            myDataTable.Columns.Add(myDataColumn);

            myDataColumn = new DataColumn();
            myDataColumn.DataType = Type.GetType("System.String");
            myDataColumn.ColumnName = "NUnit";
            myDataTable.Columns.Add(myDataColumn);


            return myDataTable;
        }

then use this data table call this on load form

datatable GridTable=new Datatable();
Gridtable=CreateDataTable();

Then You want to fill the value in table then use

AddDataToTable(this.ddlSpecification.Text.ToString(), this.ddlSpecification.SelectedValue.ToString(), this.ddlSelectBK.Text.ToString(), this.txtQTYgrosswt.Text.Trim(), this.ddlUnit.Text.Trim(), this.txtLessWt1.Text.Trim(), this.txtLessWt2.Text.Trim(), this.txtLessWt3.Text.Trim(), this.txtLessWt4.Text.Trim(), this.txtLessWt5.Text.Trim(), this.txtTotalLessWt.Text.Trim(), this.txtNetWt.Text.Trim(), this.ddlNUnit.Text.Trim(), GridTable);

above function pass the value in table  after that use blow funation

 private void AddDataToTable(string Specification, string SpId, string SelectBK, string QtyGWt, string Unit, string lesswt1, string lesswt2, string lesswt3, string lesswt4, string lesswt5, string TotalLess, string Netwt, string NUnit, DataTable myTable)
        {
            try
            {
                DataRow row;
                row = myTable.NewRow();
                //row["id"] = Guid.NewGuid().ToString();

                row["id"] = myTable.Rows.Count + 1;
                row["Specification"] = Specification;
                row["SpId"] = Convert.ToInt32(SpId);
                row["SelectBK"] = SelectBK;
                row["QtyGWt"] = QtyGWt;
                row["Unit"] = Unit;
                row["Lesswt1"] = lesswt1; row["Lesswt2"] = lesswt2; row["Lesswt3"] = lesswt3; row["Lesswt4"] = lesswt4; row["Lesswt5"] = lesswt5;
                row["TotalLess"] = TotalLess;
                row["Netwt"] = Netwt;
                row["NUnit"] = NUnit;
                myTable.Rows.Add(row);
            }
            catch (Exception)
            {
               
               // throw;
            }

          

        }

Thanks u for use this code any problem mail me
mhshry@gmail.com