javascript - 将属性添加到 TextBox 后，ListView 不会触发 ItemInserting

Question

我有一个 ListView 来将新联系人输入到我们的数据库中，在我将自定义属性添加到 InsertItemTemplate 中的文本框中以提供一些 JavaScript 功能之前，它工作得很好。

这是 ListView 的片段:

    <asp:ListView ID="lvContacts" runat="server" InsertItemPosition="LastItem">
        <LayoutTemplate>
            <div id="itemPlaceholder" runat="server">
            </div>
        </LayoutTemplate>
        <ItemTemplate>
            ...
        </ItemTemplate>
        <InsertItemTemplate>
            <div class="borderedBox">
                <h3>
                    ADD OTHER CONTACT</h3>
                <div>
                    <div class="leftFields">
                        <asp:Label ID="astContactType" runat="server" CssClass="fieldLabel">Contact Type *</asp:Label><br />
                        <asp:TextBox ID="txtContactType" runat="server"></asp:TextBox><br />
                    </div>
                    <div class="rightFields">
                        <asp:Button ID="btnAdd" runat="server" Text="ADD NEW" Style="width: 150px; margin-top: 27px; margin-left: 0px;" CommandName="Insert" />
                    </div>
                    <br style="clear: both;" />
                </div>
            </div>
            ...
        </InsertItemTemplate>
    </asp:ListView>

这工作得很好，btnAdd 命中了 ItemInserting 函数，其声明如下:

Protected Sub lvContacts_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewInsertEventArgs) Handles lvContacts.ItemInserting
    ...
End Sub

在 ItemCreated 函数中，我通过添加带有 JavaScript 函数的属性来“初始化”文本框，该代码可以有效地将虚拟文本添加到控件中，当用户单击该控件时该文本就会消失。但是，如果我保留此代码，则将不再达到 ItemInserting 功能。这是 ItemCreated 函数:

Protected Sub lvContacts_ItemCreated(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) Handles lvContacts.ItemCreated
    Dim txtContactType As TextBox = e.Item.FindControl("txtContactType")

    ControlHelper.InitialiseTextbox(txtContactType, "Contact Type")
End Sub

(This next part is in a separate file in the App_Code folder)
Public Class ControlHelper
    Public Shared Sub InitialiseTextbox(ByVal Text As TextBox, ByVal DefaultValue As String)
        Text.Text = DefaultValue
        Text.Attributes.Add("onfocus", "textFocus('" & Text.ClientID & "', '" & DefaultValue & "')")
        Text.Attributes.Add("onblur", "textBlur('" & Text.ClientID & "', '" & DefaultValue & "')")
    End Sub
End Class

通过向 TextBox 添加属性，这种初始化 TextBox 的方法可以正常工作，并且也可以正常工作。任何想法为什么当我这样做时 ItemInserting 不再起作用？

Answer 1

在 ListView 控件上添加两个事件属性，如下所示:

 <asp:ListView ID="lvContacts" runat="server" InsertItemPosition="LastItem" 
          OnItemInserting="lvContacts_ItemInserting"
          OnItemEditing="lvContacts_ItemEditing" 
          OnPreRender="lvContacts_PreRender" >

并像这样更改您的代码:

首先在类作用域中设置一个整数变量，然后在 ItemEditing 事件中将索引值设置为变量，并使用 pre_render 事件在控件上设置属性:

Private itemIndex As Integer = -1

Protected Sub lvContacts_ItemEditing(sender As Object, e As ListViewEditEventArgs)
     itemIndex = e.NewEditIndex
End Sub

Protected Sub lvContacts_PreRender(sender As Object, e As EventArgs)
    Dim txtContactType As TextBox
    If itemIndex <> -1 Then
        txtContactType = DirectCast(ListView1.Items(itemIndex).FindControl("txtContactType"), TextBox)
        ControlHelper.InitialiseTextbox(txtContactType, "Contact Type")
    End If
End Sub