Control.ChildControlsCreated Właściwość
Definicja
Ważne
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Pobiera wartość wskazującą, czy kontrolki podrzędne kontrolki serwera zostały utworzone.
protected:
property bool ChildControlsCreated { bool get(); void set(bool value); };protected bool ChildControlsCreated { get; set; }member this.ChildControlsCreated : bool with get, setProtected Property ChildControlsCreated As BooleanWartość właściwości
true jeśli kontrolki podrzędne zostały utworzone; w przeciwnym razie, false.
Przykłady
W poniższym przykładzie pokazano zastąpienie OnDataBinding metody niestandardowej Repeater kontrolki. Aby upewnić się, że kontrolki podrzędne nie zostaną utworzone do momentu ponownego utworzenia powiązania danych, ChildControlsCreated właściwość zostanie ustawiona na true po utworzeniu RepeaterItem obiektów i dodaniu ich do obiektu kontrolki 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
W poniższym przykładzie pokazano, jak używać niestandardowej kontrolki powtarzania na stronie sieci 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>
