I want to show datagrid view column header name on form load.After button click data should be binded on that column

grvVouchers.Columns.Add("SlNo", "#");
           grvVouchers.Columns.Add("Col1", "Name1");
           grvVouchers.Columns.Add("Col2", "Name2");
           grvVouchers.Columns.Add("colName", "Name5");
           grvVouchers.Columns.Add("Col3 ", "Name3");
           grvVouchers.Columns.Add("Col4", "Name4");
}

BtnClick
{
 DataTable dtGetList = new DataTable();
            dtGetList.Columns.Add("Sl No").AutoIncrement = true; //For sorting numeric values set by typeof(int), default sorting is string.
            dtGetList.Columns.Add("Columns1");
            dtGetList.Columns.Add("Columns2");
            dtGetList.Columns.Add("Columns3");
            dtGetList.Columns.Add("Columns4");
            int SlCount = 1;
            
            foreach (DataRow dr in dsGetlist.Tables["GetList"].Rows)
            {
                DataRow drGetList = dtGetList.NewRow();
                drGetList["Sl No"] = SlCount;
                drGetList["Columns1"] = dr["x1"];
                drGetList["Columns2"] = dr["x2"];
                drGetList["Columns3"] = dr["x3"];
                drGetList["Columns4"] = Convert.ToDecimal(dr["x4"]);

                dtGetList.Rows.Add(drGetList);
                SlCount++;
     
            }

            grvVouchers.DataSource = dtGetList;
}