Control.ChildControlsCreated プロパティ

[アーティクル]
06/26/2007

サーバーコントロールの子コントロールが作成されたかどうかを示す値を取得します。

名前空間: System.Web.UI
アセンブリ: System.Web (system.web.dll 内)

構文

'宣言
Protected Property ChildControlsCreated As Boolean
'使用
Dim value As Boolean

value = Me.ChildControlsCreated

Me.ChildControlsCreated = value

protected bool ChildControlsCreated { get; set; }

protected:
property bool ChildControlsCreated {
    bool get ();
    void set (bool value);
}

/** @property */
protected boolean get_ChildControlsCreated ()

/** @property */
protected void set_ChildControlsCreated (boolean value)

protected function get ChildControlsCreated () : boolean

protected function set ChildControlsCreated (value : boolean)

適用できません。

プロパティ値

子コントロールが作成された場合は true。それ以外の場合は false。

使用例

Repeater カスタムコントロールの OnDataBinding メソッドのオーバーライドを次の例に示します。再びデータバインディングが行われるまで子コントロールが作成されないようにするには、RepeaterItem オブジェクトが作成され、コントロールの ControlCollection オブジェクトに追加された後に、ChildControlsCreated プロパティを true に設定します。

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

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;
            }
        }
    }
}

Web ページで Repeater カスタムコントロールを使用する方法を次の例に示します。

<%@ 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>

<%@ 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>

プラットフォーム

Windows 98,Windows Server 2000 SP4,Windows CE,Windows Millennium Edition,Windows Mobile for Pocket PC,Windows Mobile for Smartphone,Windows Server 2003,Windows XP Media Center Edition,Windows XP Professional x64 Edition,Windows XP SP2,Windows XP Starter Edition

Microsoft .NET Framework 3.0 は Windows Vista,Microsoft Windows XP SP2,および Windows Server 2003 SP1 でサポートされています。

バージョン情報

.NET Framework

サポート対象 : 3.0,2.0,1.1,1.0

次の方法で共有

Control.ChildControlsCreated プロパティ

構文

プロパティ値

使用例

プラットフォーム

バージョン情報

.NET Framework

参照

関連項目

その他のリソース