C# 在ListView EmptyDataTemplate中查找控件
我有这样的aC# 在ListView EmptyDataTemplate中查找控件,c#,asp.net,.net,listview,findcontrol,C#,Asp.net,.net,Listview,Findcontrol,我有这样的aListView <asp:ListView ID="ListView1" runat="server"> <EmptyDataTemplate> <asp:Literal ID="Literal1" runat="server" text="some text"/> </EmptyDataTemplate> ... </asp:ListView> 但是x返回null。我想更改Literal控
ListView
<asp:ListView ID="ListView1" runat="server">
<EmptyDataTemplate>
<asp:Literal ID="Literal1" runat="server" text="some text"/>
</EmptyDataTemplate>
...
</asp:ListView>
但是
x
返回null
。我想更改Literal
控件的文本,但我不知道如何操作。我相信,除非调用ListView
中的DataBind
方法,否则ListView
将永远不会尝试数据绑定。然后将不会呈现任何内容,甚至不会创建Literal
控件
在页面\u Load
事件中,尝试以下操作:
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
//ListView1.DataSource = ...
ListView1.DataBind();
//if you know its empty empty data template is the first parent control
// aka Controls[0]
Control c = ListView1.Controls[0].FindControl("Literal1");
if (c != null)
{
//this will atleast tell you if the control exists or not
}
}
}
这不是你具体要求的,但另一种方法是:
<EmptyDataTemplate>
<%= Foobar() %>
</EmptyDataTemplate>
您可以使用以下选项:
Literal x = (Literal)ListView1.FindControl("Literal1");
x.Text = "other text";
protected void ListView1_ItemDataBound(object sender, ListViewItemEventArgs e)
{
if (e.Item.ItemType == ListViewItemType.EmptyItem)
{
Control c = e.Item.FindControl("Literal1");
if (c != null)
{
//this will atleast tell you if the control exists or not
}
}
}
…另一种方法
<asp:ListView ID="ListView1" runat="server">
<EmptyDataTemplate>
<asp:Literal ID="Literal1" runat="server" text="some text" OnInit="Literal1_Init" />
</EmptyDataTemplate>
...
</asp:ListView>
回答Broam的问题“有没有办法在databound方法中做到这一点?我不想硬编码“控件[0]”,因为这太草率了” 不幸的是,我没有找到不使用控件的方法[0] 在通常的项事件(ItemDataBound或ItemCreate)中,可以使用ListViewItemEventArgs的e.Item来获取ListViewItem。在DataBound事件中,只有一个通用的EventArgs
除此之外,似乎((Control)sender).FindControl(“Literal1”)也不起作用(从树顶部的listview中查找控件),因此使用了控件[0]。FindControl(…)(从listviewitem中查找控件)。在数据绑定方法中有什么方法可以做到这一点吗?我不想硬编码“controls[0]”,因为这太草率了。如果我去掉
。controls[0]
我会出错。你能帮我理解你为什么需要它吗?我们似乎在告诉它控件的索引和名称,我不明白为什么两者都是必需的。@Nick.Controls[0]是对EmptyDataTemplate对象的引用。对该对象进行引用后,将在EmptyDataTemplate的子控件中查找名为“Literal1”的控件。这将发现EmptyItemTemplate。还有一个EmptyDataTemplate,这将不会看到。
Protected Sub ListView1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) Handles ListView1.ItemDataBound
Dim searchValue As String = Replace(Request.QueryString("s"), "", "'")
Dim searchLiteral2 As Literal = CType(ListView1.FindControl("Literal2"), Literal)
searchLiteral2.Text = "''" & searchValue & "''"
End Sub
<asp:ListView ID="ListView1" runat="server">
<EmptyDataTemplate>
<asp:Literal ID="Literal1" runat="server" text="some text" OnInit="Literal1_Init" />
</EmptyDataTemplate>
...
</asp:ListView>
protected void Literal1_Init(object sender, EventArgs e)
{
(sender as Literal).Text = "Some other text";
}
protected void ListView1_DataBound(object sender, EventArgs e)
{
ListView mylist = ((ListView)sender);
ListViewItem lvi = null;
if (mylist.Controls.Count == 1)
lvi = mylist.Controls[0] as ListViewItem;
if (lvi == null || lvi.ItemType != ListViewItemType.EmptyItem)
return;
Literal literal1 = (Literal)lvi.FindControl("Literal1");
if (literal1 != null)
literal1.Text = "No items to display";
}