Control.ChildControlsCreated Control.ChildControlsCreated Control.ChildControlsCreated Control.ChildControlsCreated Property

定義

取得值,指出是否已經建立伺服器控制項的子控制項。Gets a value that indicates whether the server control's child controls have been created.

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

屬性值

如果子控制項已經建立,則為 true,否則為 falsetrue if child controls have been created; otherwise, false.

範例

下列範例示範的覆寫OnDataBinding方法的自訂Repeater控制項。The following example demonstrates an override of the OnDataBinding method of a custom Repeater control. 若要確保子控制項都不會建立資料繫結,就會發生一次,直到ChildControlsCreated屬性設定為true之後RepeaterItem所建立的物件,並將其加入控制項的ControlCollection物件。To ensure that child controls are not created until data binding occurs again, the ChildControlsCreated property is set to true after the RepeaterItem objects are created and added to the control's ControlCollection object.

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
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

下列範例示範如何使用自訂的 repeater 控制項在網頁中。The following example demonstrates how to use the custom repeater control in a Web page.

<%@ 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>

適用於

另請參閱