Bind Dropdown List

bind dropdown with for loop

            ddlPaymentTerms.Items.Clear();
            ddlPaymentTerms.Items.Add("Select...");
            ddlPaymentTerms.Items.Add("NA");
            dt = objGeneral.Common_GetDetails();
            ddlPaymentTerms.DataTextField = "paytypes";
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                ddlPaymentTerms.Items.Add(dt.Rows[i][0].ToString());
                ddlPaymentTerms.DataBind();
            }

After binding display selected item in drop down

ddlPaymentTerms.SelectedIndex = 5;

bind dropdown with text field and value field

for (int i = 0; dt.Rows.Count > i; i++)
        {
            tdscategory.Items.Clear();
            tdscategory.DataTextField = "TDSCategoryName";
            tdscategory.DataValueField = "LedgerCode";
            tdscategory.DataSource = dt;
            tdscategory.DataBind();
          
        }