Asp.Net RadioButtonList 选定的 ListItem 在页面重新访问时无法识别

Question

在我的送货地址页面上有两个 RadioButtonList ListItems（代码如下所示），它们根据用户输入写入数据库 true 或 false。

用户第一次选择一个值并进入结账流程的下一步时，他们的送货地址类型会正确（真/假）存储在数据库中。如果他们返回送货地址页面，选择相反的 ListItem 并转到下一个结账页面，则数据库中更新后的送货类型不会更改。就好像在重新访问页面时 ListItem 无法识别用户的单选按钮选择已更改一样。

有人可以帮忙解决这个问题吗？

ShippingAddress.ascx

<asp:RadioButtonList id="ShipToAddressType" runat="server">
    <asp:ListItem Value="0" id="businessShipping">My shipping address is a business.</asp:ListItem>
    <asp:ListItem Value="1" id="residenceShipping">My shipping address is a residence.</asp:ListItem>
</asp:RadioButtonList>

ShippingAddress.ascx.cs

if (residenceShipping.Selected == true)
    shippingAddress.Residence = true;
else
    shippingAddress.Residence = false;

ShippingAddress.ascx.cs Page_Load

protected void Page_Load(object sender, EventArgs e)
{
    User user = Token.Instance.User;

    Address shipAddress = null;

    foreach (Address tempAddress in user.Addresses) if (tempAddress.Nickname == "Shipping") shipAddress = tempAddress;

    // sets radio button of return users previously selected ship type
    if (shipAddress != null)
    {
        if (shipAddress.Residence == false)
        {
            ShipToAddressType.SelectedIndex = 0;
        }
        else
        {
            ShipToAddressType.SelectedIndex = 1;
        }
    }
}

Answer 1

您需要将Page_Load中的代码移至Page_Init。否则 ViewState 将无法工作，并且您将不会收到更改事件。视图状态在 Init 之后、PreLoad 之前加载。

您还应该将初始化代码包装在 IsPostBack 检查中。尽管我可能会误解你在这里所做的事情。

protected void Page_Init(EventArgs e)
{
    if (!IsPostBack)
    {
        User user = Token.Instance.User;

        Address shipAddress = null;

        foreach (Address tempAddress in user.Addresses)
        {
            if (tempAddress.Nickname != "Shipping")
            {
                continue;
            }
            ShipToAddressType.SelectedIndex = 1;
        }
    }
    ShipToAddressType.SelectedIndexChanged += ShipToAddressType_SelectedIndexChanged;
}

void ShipToAddressType_SelectedIndexChanged(object sender, EventArgs e)
{
    // save the new state to database

    // redirect to enforce refresh of saved state
    Response.Redirect(Request.RawUrl);
}