How to add dropdown list in excel For particular column's all the rows.

A   B    C  
1  aaa  DDL  
.  bbb  DDL
.  ccc	DDL	
.
.
.
1000

int iRowCount = Table1.Tables[0].Rows.Count;

        string[] ddl_item = { "Answers", "Autos", "Finance", "Games", "Groups" };

        for (int j = 2; j < iRowCount; j++)
        {
            xlsRange = xlWorkSheet.get_Range("A" + j, "A" + j);
            Excel.DropDowns xlDropDowns;
            Excel.DropDown xlDropDown;
            xlDropDowns = ((Excel.DropDowns)(xlWorkSheet.DropDowns(oMissing)));
            xlDropDown = xlDropDowns.Add((double)xlsRange.Left, (double)xlsRange.Top, (double)xlsRange.Width, (double)xlsRange.Height, true);

            for (int i = 0; i < ddl_item.Length; i++)
            {
                xlDropDown.AddItem(ddl_item[i], i + 1);
            }
        }