Control.ChildControlsCreated Properti
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Mendapatkan nilai yang menunjukkan apakah kontrol anak kontrol server telah dibuat.
protected:
property bool ChildControlsCreated { bool get(); void set(bool value); };
protected bool ChildControlsCreated { get; set; }
member this.ChildControlsCreated : bool with get, set
Protected Property ChildControlsCreated As Boolean
Nilai Properti
true
jika kontrol anak telah dibuat; jika tidak, false
.
Contoh
Contoh berikut menunjukkan penimpaan OnDataBinding metode kontrol kustom Repeater . Untuk memastikan bahwa kontrol anak tidak dibuat sampai pengikatan data terjadi lagi, ChildControlsCreated properti diatur ke true
setelah RepeaterItem objek dibuat dan ditambahkan ke objek kontrol ControlCollection .
using System;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace TemplateControlSamples
{
[ParseChildren(true)]
public class CustomRepeater : Repeater
{
// Override to prevent LiteralControls from being added as children.
protected override void AddParsedSubObject(object o)
{
}
// Override to create repeated items.
protected override void CreateChildControls()
{
object o = ViewState["NumItems"];
if (o != null)
{
// Clear any existing child controls.
Controls.Clear();
int numItems = (int)o;
for (int i = 0; i < numItems; i++)
{
// Create an item.
RepeaterItem item = new RepeaterItem(i, ListItemType.Item);
// Initialize the item from the template.
ItemTemplate.InstantiateIn(item);
// Add the item to the ControlCollection.
Controls.Add(item);
}
}
}
// Override to create the repeated items from the DataSource.
protected override void OnDataBinding(EventArgs e)
{
base.OnDataBinding(e);
if (DataSource != null)
{
// Iterate over an ICollection DataSource, creating a new item for each data item.
IEnumerator dataEnum = ((ICollection)base.DataSource).GetEnumerator();
int i = 0;
while (dataEnum.MoveNext())
{
// Create an item.
RepeaterItem item = new RepeaterItem(i, ListItemType.Item);
item.DataItem = dataEnum.Current;
// Initialize the item from the template.
ItemTemplate.InstantiateIn(this);
// Add the item to the ControlCollection.
Controls.Add(item);
i++;
}
// Prevent child controls from being created again.
ChildControlsCreated = true;
// Store the number of items created in view state for postback scenarios.
ViewState["NumItems"] = i;
}
}
}
}
Imports System.Collections
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Namespace TemplateControlSamplesVB
<ParseChildren(True)> _
Public Class CustomRepeaterVB : Inherits Repeater
' Override to prevent LiteralControls from being added as children.
Protected Overrides Sub AddParsedSubObject(ByVal O As Object)
End Sub
' Override to create repeated items.
Protected Overrides Sub CreateChildControls()
Dim O As Object = ViewState("NumItems")
If Not (O Is Nothing) Then
' Clear any existing child controls.
Controls.Clear()
Dim i As Integer
Dim NumItems As Integer = CInt(O)
For i = 0 To NumItems - 1
' Create an item.
Dim Item As RepeaterItem = New RepeaterItem(i, ListItemType.Item)
' Initialize the item from the template.
ItemTemplate.InstantiateIn(Item)
' Add the item to the ControlCollection.
Controls.Add(Item)
Next
End If
End Sub
' Override to create the repeated items from the DataSource.
Protected Overrides Sub OnDataBinding(ByVal E As EventArgs)
MyBase.OnDataBinding(E)
If Not DataSource Is Nothing Then
' Iterate over the DataSource, creating a new item for each data item.
Dim DataEnum As IEnumerator = DataSource.GetEnumerator()
Dim i As Integer = 0
Do While (DataEnum.MoveNext())
' Create an item.
Dim Item As RepeaterItem = New RepeaterItem(i, ListItemType.Item)
' Initialize the item from the template.
ItemTemplate.InstantiateIn(Item)
' Add the item to the ControlCollection.
Controls.Add(Item)
i = i + 1
Loop
' Prevent child controls from being created again.
ChildControlsCreated = True
' Store the number of items created in view state for postback scenarios.
ViewState("NumItems") = i
End If
End Sub
End Class
End Namespace
Contoh berikut menunjukkan cara menggunakan kontrol pengulang kustom di halaman Web.
<%@ Page Language="C#" %>
<%@ Register TagPrefix="Samples" Namespace="TemplateControlSamples" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
ArrayList a = new ArrayList();
a.Add("data item 1");
a.Add("data item 2");
Repeater1.DataSource = a;
Page.DataBind();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ChildControlsCreated Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<Samples:CustomRepeater ID="Repeater1" runat="server">
<ItemTemplate><%# Container.DataItem %> <br /></ItemTemplate>
</Samples:CustomRepeater>
</div>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Register TagPrefix="Samples" Namespace="TemplateControlSamplesVB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Dim a As New ArrayList()
a.Add("data item 1")
a.Add("data item 2")
Repeater1.DataSource = a
Page.DataBind()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ChildControlsCreated Example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<Samples:CustomRepeaterVB ID="Repeater1" runat="server">
<ItemTemplate><%# Container.DataItem %> <br /></ItemTemplate>
</Samples:CustomRepeaterVB>
</div>
</form>
</body>
</html>