CompositeDataBoundControl.CreateChildControls CompositeDataBoundControl.CreateChildControls CompositeDataBoundControl.CreateChildControls CompositeDataBoundControl.CreateChildControls Method

Definition

Creates the control hierarchy that is used to render a composite data-bound control.

Overloads

CreateChildControls() CreateChildControls() CreateChildControls() CreateChildControls()

Creates the control hierarchy that is used to render a composite data-bound control based on the values that are stored in view state.

CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean)

When overridden in an abstract class, creates the control hierarchy that is used to render the composite data-bound control based on the values from the specified data source.

CreateChildControls() CreateChildControls() CreateChildControls() CreateChildControls()

Creates the control hierarchy that is used to render a composite data-bound control based on the values that are stored in view state.

protected public:
 override void CreateChildControls();
protected internal override void CreateChildControls ();
override this.CreateChildControls : unit -> unit
Protected Friend Overrides Sub CreateChildControls ()

Remarks

The CreateChildControls() method is a helper method that is used by classes that derive from the CompositeDataBoundControl class to create the control hierarchy for a composite data-bound control. This overload of the method creates the control hierarchy based on values from view state, rather than directly from the data source.

See also

CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean) CreateChildControls(IEnumerable, Boolean)

When overridden in an abstract class, creates the control hierarchy that is used to render the composite data-bound control based on the values from the specified data source.

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

Parameters

dataSource
IEnumerable IEnumerable IEnumerable IEnumerable

An IEnumerable that contains the values to bind to the control.

dataBinding
Boolean Boolean Boolean Boolean

true to indicate that the CreateChildControls(IEnumerable, Boolean) is called during data binding; otherwise, false.

Returns

The number of items created by the CreateChildControls(IEnumerable, Boolean).

Examples

The following code example demonstrates how to override the CreateChildControls(IEnumerable, Boolean) method in a custom control to create the control hierarchy.

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
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 'SimpleSpreadsheetControl


    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 'New

        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 'RenderContents
    End Class 'SimpleSpreadsheetRow
End Namespace

Remarks

The CreateChildControls() method is a helper method that is used by classes that derive from the CompositeDataBoundControl class to create the control hierarchy for a composite data-bound control. When extending the CompositeDataBoundControl class, you must override the CreateChildControls() method to create your own control hierarchy. For more information on creating a composite control, see Developing Custom ASP.NET Server Controls.

See also

Applies to