<asp:DropDownList ID="DropDownList1" runat="server">
    <asp:ListItem Value="設計家園">設計家園</asp:ListItem>
    <asp:ListItem Value="網頁設計">網頁設計</asp:ListItem>
    <asp:ListItem Value="網絡編程">網絡編程</asp:ListItem>
    <asp:ListItem Value="酷站欣賞">酷站欣賞</asp:ListItem>
</asp:DropDownList>

SqlConnection conn = system.Configuration.ConfigurationSettings.AppSettings["SqlConnection"].ToString();
string strSQL = "select * from CompanyType";
SqlDataAdapter ada = new SqlDataAdapter(strSQL, conn);
DataSet ds = new DataSet();
ada.Fill(ds, "CompanyType");
DropDownList1.DataSource = ds.Tables["CompanyType"].DefaultView;
DropDownList1.DataValueField = ds.Tables["CompanyType"].Columns[1].ColumnName;
DropDownList1.DataTextField = ds.Tables["CompanyType"].Columns[1].ColumnName;
DropDownList1.DataBind();
ds.Dispose();

//其中datavaluefield屬性是控件的一個關鍵屬性，cs頁面通過value值獲??；
//而datatextfield是顯示在視圖頁面的文本。

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        SqlConnection conn = system.Configuration.ConfigurationSettings.AppSettings["SqlConnection"].ToString();
        try
        {
conn.Open();
this.DropDownList1.Items.Add("");
string strSQL = "select CompanyType from CompanyType";
SqlCommand com = new SqlCommand(strSQL, conn);
SqlDataReader dr = com.ExecuteReader();
while (dr.Read())
        {
        this.DropDownList1.Items.Add(dr["CompanyType"].ToString());
        //或者
        //DropDownList_name.Items.Add(new ListItem(TEXT, Value));
    }
}
catch (Exception ex)
{
    Response.Write("<scirpt>alert('" + ex.Message.ToString() + "')</script>");
}
finally
{
    conn.Close();
}
}
}

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DropDownList2.Items.Clear();
        if (DropDownList1.Items[0].Selected)
        {
DropDownList2.Items.Add("陸小鳳");
DropDownList2.Items.Add("楚留香");
        }
        else
        {
DropDownList2.Items.Add("楊過");
DropDownList2.Items.Add("小龍女");
        }
    }

DataSet Ds = null;
string SqlStr = null;
SqlServer sqlserverDB = new SqlServer();
SqlStr = "select name,account from qdvc_usersimple";
Ds = sqlserverDB.DataSetRun(null, SqlStr, "qdvc_usersimple");
foreach (DataRow dataRow in Ds.Tables[0].Rows)
{
    object[] itemArray = dataRow.ItemArray; //獲取dataRow的所有的單元格里的數據Array
    // itemArray[0].ToString()是"name",itemArray[1].ToString()是"account"
    DropDownList_name.Items.Add(new ListItem(itemArray[0].ToString(), itemArray[1].ToString()));
}