Code sample like as follows
Markup
<asp:dropdownlist id="ddlDays" runat="server" xmlns:asp="#unknown">
<asp:button id="btnSave" text="Save" runat="server" onclick="btnSave_Click" xmlns:asp="#unknown">
CodeBehind
Page load event
protected void Page_Load(object sender, EventArgs e)
{
if (!base.IsPostBack)
{
ddlDays.DataSource = GetDataTable();
ddlDays.DataTextField = "DelayDays";
ddlDays.DataValueField = "ID";
ddlDays.DataBind();
}
}
Save button click event handler
protected void btnSave_Click(object sender, EventArgs e)
{
int selectedId = int.Parse(ddlDays.SelectedValue);
}
sample data provider method
private DataTable GetDataTable()
{
var dt = new DataTable("DataTabl1");
dt.Columns.Add("ID", typeof(Int32));
dt.Columns.Add("DelayDays", typeof(Int32));
DataRow row1 = dt.NewRow();
row1["ID"] = 6;
row1["DelayDays"] = 0;
dt.Rows.Add(row1);
row1 = dt.NewRow();
row1["ID"] = 8;
row1["DelayDays"] = 3;
dt.Rows.Add(row1);
row1 = dt.NewRow();
row1["ID"] = 9;
row1["DelayDays"] = 7;
dt.Rows.Add(row1);
return dt;
}