html:
省份<asp:DropDownList ID="dropProvince"
runat="server" AutoPostBack="True"
onselectedindexchanged="dropProvince_SelectedIndexChanged">
<asp:ListItem Text="湖南" Value="1"></asp:ListItem>
<asp:ListItem Text="湖北" Value="2"></asp:ListItem>
</asp:DropDownList>
城市<asp:DropDownList ID="dropCity" runat="server">
</asp:DropDownList>
后台代码:
加一个方法
protected void dropProvince_SelectedIndexChanged(object sender, EventArgs e)
{
dropCity.Items.Clear();
if (dropProvince.SelectedValue == "1")
{
dropCity.Items.Add(new ListItem { Text = "长沙", Value = "1" });
dropCity.Items.Add(new ListItem { Text = "株洲", Value = "2" });
}
else if (dropProvince.SelectedValue == "2")
{
dropCity.Items.Add(new ListItem { Text = "武昌", Value = "3" });
dropCity.Items.Add(new ListItem { Text = "汉口", Value = "4" });
}
}