DetailsView - ItemUpdating 中的值未更改

Question

我将 DetailsView 绑定到一个对象。当调用 ItemUpdating 时（当我点击更新时）OldValues 为空并且 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>

后面的代码：

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

看到这个答案：OldValues collection in event "ItemUpdating" of DetailsView is always empty

这似乎只有在您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在设置新的数据源，即使它是 post-back。

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();
    }
}

看不到旧值，但新值看起来是正确的。

DetailsView - ItemUpdating 中的值未更改

DetailsView - Values not changing in ItemUpdating

.net

c#

asp.net

webforms