回发后如何获取动态控件的值？
我有一个在 ItemDataBound 事件中添加控件的列表视图。当回发发生时，我找不到新的控件。经过一番研究，我发现 ASP .NET 每次都需要创建这些控件，即使在回发之后也是如此。从那里，我将函数移至 if (!Page.IsPostBack) 条件之外绑定 ListView。现在我得到了动态控件值，但我拥有的静态控件被设置为默认值。以下是我想要完成的任务的示例：
为了简洁起见，我在这个示例中省略了一些明显的事情。
<asp:ListView runat="server" ID="MyList" OnItemDataBound="MyList_ItemDataBound">
<LayoutTemplate>
<asp:PlaceHolder runat="server" ID="itemPlaceholder" />
</LayoutTemplate>
<ItemTemplate>
<asp:PlaceHolder runat="server" ID="ProductPlaceHolder">
<asp:TextBox runat="server" ID="StaticField" Text="DefaultText" />
<asp:PlaceHolder ID="DynamicItems" runat="server" />
</asp:PlaceHolder>
</ItemTemplate>
</asp:ListView>
这是隐藏的代码：
protected void MyList_ItemDataBound(object sender, System.Web.UI.WebControls.ListViewItemEventArgs e) {
PlaceHolder DynamicItems = (PlaceHolder)e.Item.FindControl("DynamicItems");
DynamicItems.Controls.Add(textbox);
}
所以，就像我说的，如果我只在 Page != PostBack 时进行数据绑定，那么我无法在回发时找到动态控件。如果我每次加载页面时都进行绑定，那么我的静态字段就会设置为其默认文本。
I have a listview that adds controls in the ItemDataBound Event. When the postback occurs, I cannot find the new controls. After a bit of research, I found that ASP .NET needs these controls created every time, even after postback. From there I moved the function to bind the ListView outside of the if (!Page.IsPostBack) conditional. Now I get the dynamic controls values but the static controls I have are set to their defaults. Here is a sample of what I am trying to accomplish:
For brevity, I left some obvious things out of this example.
<asp:ListView runat="server" ID="MyList" OnItemDataBound="MyList_ItemDataBound">
<LayoutTemplate>
<asp:PlaceHolder runat="server" ID="itemPlaceholder" />
</LayoutTemplate>
<ItemTemplate>
<asp:PlaceHolder runat="server" ID="ProductPlaceHolder">
<asp:TextBox runat="server" ID="StaticField" Text="DefaultText" />
<asp:PlaceHolder ID="DynamicItems" runat="server" />
</asp:PlaceHolder>
</ItemTemplate>
</asp:ListView>
and here is the codebehind:
protected void MyList_ItemDataBound(object sender, System.Web.UI.WebControls.ListViewItemEventArgs e) {
PlaceHolder DynamicItems = (PlaceHolder)e.Item.FindControl("DynamicItems");
DynamicItems.Controls.Add(textbox);
}
So, like I said, if I only databind when Page != PostBack then I cant find my dynamic controls on postback. If I bind every time the page loads then my static fields get set to their default text.
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尝试将 ListView 的数据绑定移至 OnInit() 事件中。
Try moving the data binding of the ListView into the OnInit() event.
非常相似的问题（而不是填充 ListView 时，这家伙正在生成一组按钮）。简而言之，您会发现必须将列表中的项目存储在 Viestate 中 - 而不是在 Postback 上将其取出并重新填充列表。
请注意，此解决方案意味着删除数据绑定（您可能出于其他原因不想这样做）。
希望有帮助。
Very similar question (instead of populating a ListView the guy is generating a set of buttons). Briefly, you'll find that you have to store the items in the list in your Viestate - than fish it out on Postback and re-populate the list.
Note that this solutions implies dropping data-binding (which you might not wanna do for others reasons).
Hope it helps.