CompositeDataBoundControl.CreateChildControls 方法

参考

定义

命名空间:: System.Web.UI.WebControls

程序集:: System.Web.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

创建用于呈现复合数据绑定控件的控件层次结构。

重载

CreateChildControls()	基于存储在视图状态中的值创建用来呈现复合数据绑定控件的控件层次结构。
CreateChildControls(IEnumerable, Boolean)	当在抽象类中重写时，基于指定数据源中的值创建用来呈现复合数据绑定控件的控件层次结构。

CreateChildControls()

基于存储在视图状态中的值创建用来呈现复合数据绑定控件的控件层次结构。

protected public:
 override void CreateChildControls();

protected internal override void CreateChildControls ();

override this.CreateChildControls : unit -> unit

Protected Friend Overrides Sub CreateChildControls ()

注解

该方法 CreateChildControls() 是派生自类的 CompositeDataBoundControl 类用来为复合数据绑定控件创建控件层次结构的帮助程序方法。此方法的重载基于视图状态的值而不是直接从数据源创建控件层次结构。

另请参阅

CreateChildControls()

适用于

CreateChildControls(IEnumerable, Boolean)

当在抽象类中重写时，基于指定数据源中的值创建用来呈现复合数据绑定控件的控件层次结构。

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

参数

dataSource: IEnumerable

一个 IEnumerable，它包含要绑定到控件的值。

dataBinding: Boolean

如果为 true，则指示在数据绑定期间调用 CreateChildControls(IEnumerable, Boolean)；否则为 false。

Int32

由 CreateChildControls(IEnumerable, Boolean) 创建的项的数量。

示例

下面的代码示例演示如何重写 CreateChildControls(IEnumerable, Boolean) 自定义控件中的方法以创建控件层次结构。

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

注解

该方法 CreateChildControls() 是派生自类的 CompositeDataBoundControl 类用来为复合数据绑定控件创建控件层次结构的帮助程序方法。扩展 CompositeDataBoundControl 类时，必须重写 CreateChildControls() 方法以创建自己的控件层次结构。有关创建复合控件的详细信息，请参阅开发自定义 ASP.NET 服务器控件。

另请参阅

适用于

CompositeDataBoundControl.CreateChildControls 方法

定义

重载

CreateChildControls()

注解

另请参阅

适用于

CreateChildControls(IEnumerable, Boolean)

参数

返回

示例

注解

另请参阅

适用于

其他资源