CompositeDataBoundControl.CreateChildControls 方法

參考

定義

命名空間:: System.Web.UI.WebControls

組件:: System.Web.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

建立用來呈現複合資料繫結控制項的控制項階層架構。

多載

CreateChildControls()	根據儲存在檢視狀態中的值，建立用來呈現複合資料繫結控制項的控制項階層架構。
CreateChildControls(IEnumerable, Boolean)	在抽象類別中被覆寫時，根據指定之資料來源中的值，建立用來呈現複合資料繫結控制項的控制項階層架構。

CreateChildControls()

根據儲存在檢視狀態中的值，建立用來呈現複合資料繫結控制項的控制項階層架構。

protected public:
 override void CreateChildControls();

protected internal override void CreateChildControls ();

override this.CreateChildControls : unit -> unit

Protected Friend Overrides Sub CreateChildControls ()

備註

方法是 CreateChildControls() 協助程式方法，由衍生自類別的 CompositeDataBoundControl 類別用來建立複合資料繫結控制項的控制項階層。這個方法的多載會根據檢視狀態的值建立控制項階層，而不是直接從資料來源建立。

另請參閱

CreateChildControls()

適用於

CreateChildControls(IEnumerable, Boolean)

在抽象類別中被覆寫時，根據指定之資料來源中的值，建立用來呈現複合資料繫結控制項的控制項階層架構。

protected:
 abstract int CreateChildControls(System::Collections::IEnumerable ^ dataSource, bool dataBinding);

protected abstract int CreateChildControls (System.Collections.IEnumerable dataSource, bool dataBinding);

override this.CreateChildControls : System.Collections.IEnumerable * bool -> int

Protected MustOverride Function CreateChildControls (dataSource As IEnumerable, dataBinding As Boolean) As Integer

參數

dataSource: IEnumerable

IEnumerable，包含要繫結至控制項的值。

dataBinding: Boolean

true 表示會在資料繫結 (Data Binding) 期間呼叫 CreateChildControls(IEnumerable, Boolean)，否則為 false。

傳回

Int32

由 CreateChildControls(IEnumerable, Boolean) 所建立之項目的數目。

範例

下列程式碼範例示範如何覆寫 CreateChildControls(IEnumerable, Boolean) 自訂控制項中的方法，以建立控制項階層。

using System;
using System.Collections;
using System.Data.Common;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Samples.AspNet.CS
{
    public class SimpleSpreadsheetControl : CompositeDataBoundControl
    {
        protected Table table = new Table();

        public virtual TableRowCollection Rows
        {
            get
            {
                return table.Rows;
            }
        }

        protected override int CreateChildControls(IEnumerable dataSource, bool dataBinding)
        {

            int count = 0;
            // If dataSource is not null, iterate through it and
            // extract each element from it as a row, then
            // create a SimpleSpreadsheetRow and add it to the
            // rows collection.
            if (dataSource != null)
            {

                SimpleSpreadsheetRow row;
                IEnumerator e = dataSource.GetEnumerator();

                while (e.MoveNext())
                {
                    object datarow = e.Current;
                    row = new SimpleSpreadsheetRow(count, datarow);
                    this.Rows.Add(row);
                    ++count;
                }

                Controls.Add(table);
            }
            return count;
        }
    }

    //
    //
    public class SimpleSpreadsheetRow : TableRow, IDataItemContainer
    {
        private object data;
        private int _itemIndex;

        public SimpleSpreadsheetRow(int itemIndex, object o)
        {
            data = o;
            _itemIndex = itemIndex;
        }

        public virtual object Data
        {
            get
            {
                return data;
            }
        }
        object IDataItemContainer.DataItem
        {
            get
            {
                return Data;
            }
        }
        int IDataItemContainer.DataItemIndex
        {
            get
            {
                return _itemIndex;
            }
        }
        int IDataItemContainer.DisplayIndex
        {
            get
            {
                return _itemIndex;
            }
        }
        protected override void RenderContents(HtmlTextWriter writer)
        {

            if (Data != null)
            {
                if (Data is System.Data.Common.DbDataRecord)
                {
                    DbDataRecord temp = (DbDataRecord)Data;
                    for (int i = 0; i < temp.FieldCount; ++i)
                    {
                        writer.Write("<TD>");
                        writer.Write(temp.GetValue(i).ToString());
                        writer.Write("</TD>");
                    }
                }
                else
                {
                    writer.Write("<TD>" + Data.ToString() + "</TD>");
                }
            }

            else
            {
                writer.Write("<TD>This is a test</TD>");
            }
        }
    }
}

Imports System.Collections
Imports System.Data.Common
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.VB

    Public Class SimpleSpreadsheetControl
        Inherits CompositeDataBoundControl

        Protected table As New Table()

        Public Overridable ReadOnly Property Rows() As TableRowCollection
            Get
                Return table.Rows
            End Get
        End Property


        Protected Overrides Function CreateChildControls(ByVal dataSource As IEnumerable, ByVal dataBinding As Boolean) As Integer

            Dim count As Integer = 0
            ' If dataSource is not Nothing, iterate through it and
            ' extract each element from it as a row, then
            ' create a SimpleSpreadsheetRow and add it to the
            ' rows collection.
            If Not (dataSource Is Nothing) Then

                Dim row As SimpleSpreadsheetRow
                Dim e As IEnumerator = dataSource.GetEnumerator()

                While e.MoveNext()
                    Dim datarow As Object = e.Current
                    row = New SimpleSpreadsheetRow(count, datarow)
                    Me.Rows.Add(row)
                    count += 1
                End While

                Controls.Add(table)
            End If
            Return count
        End Function 'CreateChildControls
    End Class


    Public Class SimpleSpreadsheetRow
        Inherits TableRow
        Implements IDataItemContainer

        Private dataObj As Object
        Private _itemIndex As Integer

        Public Sub New(ByVal itemIndex As Integer, ByVal o As Object)
            dataObj = o
            _itemIndex = itemIndex
        End Sub

        Public Overridable ReadOnly Property Data() As Object
            Get
                Return dataObj
            End Get
        End Property

        ReadOnly Property DataItem() As Object Implements IDataItemContainer.DataItem
            Get
                Return Data
            End Get
        End Property

        ReadOnly Property DataItemIndex() As Integer Implements IDataItemContainer.DataItemIndex
            Get
                Return _itemIndex
            End Get
        End Property

        ReadOnly Property DisplayIndex() As Integer Implements IDataItemContainer.DisplayIndex
            Get
                Return _itemIndex
            End Get
        End Property
        Protected Overrides Sub RenderContents(ByVal writer As HtmlTextWriter)

            If Not (Data Is Nothing) Then
                If TypeOf Data Is System.Data.Common.DbDataRecord Then
                    Dim temp As DbDataRecord = CType(Data, DbDataRecord)
                    Dim i As Integer

                    While i < temp.FieldCount
                        writer.Write("<TD>")
                        writer.Write(temp.GetValue(i).ToString())
                        writer.Write("</TD>")
                        i += 1
                    End While
                Else
                    writer.Write(("<TD>" + Data.ToString() + "</TD>"))
                End If

            Else
                writer.Write("<TD>This is a test</TD>")
            End If
        End Sub
    End Class
End Namespace

備註

方法是 CreateChildControls() 協助程式方法，由衍生自類別的 CompositeDataBoundControl 類別用來建立複合資料繫結控制項的控制項階層。擴充 CompositeDataBoundControl 類別時，您必須覆寫 CreateChildControls() 方法來建立自己的控制項階層。如需建立複合控制項的詳細資訊，請參閱開發自訂 ASP.NET 伺服器控制項。

另請參閱

適用於

CompositeDataBoundControl.CreateChildControls 方法

定義

多載

CreateChildControls()

備註

另請參閱

適用於

CreateChildControls(IEnumerable, Boolean)

參數

傳回

範例

備註

另請參閱

適用於

其他資源