Question

我将DetailsView绑定到一个对象。调用ItemUpdating时（单击更新时）OldValues为空，NewValues包含旧值（与更新前相同）。

<asp:DetailsView ID="CustomerDetailsView" runat="server"
    DefaultMode="Edit"
    AutoGenerateRows="false"
    OnItemUpdating="CustomerDetailsView_ItemUpdating"
    >
    <Fields>
        <asp:BoundField DataField="LastName" HeaderText="Last name" ReadOnly="True" />
        <asp:BoundField DataField="FirstName" HeaderText="First name" ReadOnly="True" />
        <%-- Other fields ... --%>
        <asp:CommandField ShowEditButton="true" />
    </Fields>
</asp:DetailsView>

代码背后：

private Customer customer;
protected void Page_Load(object sender, EventArgs e)
{
    using (var context = new CustomersContext())
    {
        customer = context.Logins.First();
    }

    CustomerDetailsView.DataSource = new List<Customer>() { customer };
    CustomerDetailsView.DataBind();
}

protected void CustomerDetailsView_ItemUpdating(object sender, DetailsViewUpdateEventArgs e)
{
    // e.OldValues.Count == 0
    // e.NewValues["FirstName"] - is same as taken from database
}

Answer 1

请参阅此答案：OldValues collection in event "ItemUpdating" of DetailsView is always empty

看来这只有在使用绑定到数据源控件的DataSourceID属性时才有效。

Answer 2

愚蠢的我，每次重新加载页面时我都会设置新的DataSource，即使它是回发的。

应该是：

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        using (var context = new CustomersContext())
        {
            customer = context.Logins.First();
        }

        CustomerDetailsView.DataSource = new List<Customer>() { customer };
        CustomerDetailsView.DataBind();
    }
}

无法看到OldValues但NewValues看起来是正确的。

DetailsView - ItemUpdating中不更改的值

2 个答案: