Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.Security.Permissions
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.Controls.VB

<AspNetHostingPermission(SecurityAction.Demand, _
    Level:=AspNetHostingPermissionLevel.Minimal), _
    AspNetHostingPermission(SecurityAction.InheritanceDemand, _
    Level:=AspNetHostingPermissionLevel.Minimal)> _
  Public Class TextBoxSet
    Inherits DataBoundControl

    Private alBoxSet As IList

    Public ReadOnly Property BoxSet() As IList
        Get
            If alBoxSet Is Nothing Then
                alBoxSet = New ArrayList()
            End If
            Return alBoxSet
        End Get
    End Property

    Public Property DataTextField() As String
        Get
            Dim o As Object = ViewState("DataTextField")
            If o Is Nothing Then
                Return String.Empty
            Else
                Return CStr(o)
            End If
        End Get
        Set(ByVal value As String)
            ViewState("DataTextField") = value
            If (Initialized) Then
                OnDataPropertyChanged()
            End If
        End Set
    End Property

    Protected Overrides Sub PerformSelect()

        ' Call OnDataBinding here if bound to a data source using the 
        ' DataSource property (instead of a DataSourceID) because the 
        ' data-binding statement is evaluated before the call to GetData.
        If Not IsBoundUsingDataSourceID Then
            OnDataBinding(EventArgs.Empty)
        End If

        ' The GetData method retrieves the DataSourceView object from the 
        ' IDataSource associated with the data-bound control.            
        GetData().Select(CreateDataSourceSelectArguments(), _
            AddressOf OnDataSourceViewSelectCallback)

        ' The PerformDataBinding method has completed.
        RequiresDataBinding = False
        MarkAsDataBound()

        ' Raise the DataBound event.
            OnDataBound(EventArgs.Empty)

    End Sub 'PerformSelect

    Private Sub OnDataSourceViewSelectCallback(ByVal retrievedData As IEnumerable)

        ' Call OnDataBinding only if it has not already
        ' been called in the PerformSelect method.
        If IsBoundUsingDataSourceID Then
            OnDataBinding(EventArgs.Empty)
        End If
        ' The PerformDataBinding method binds the data in the retrievedData 
        ' collection to elements of the data-bound control.
        PerformDataBinding(retrievedData)

    End Sub 'OnDataSourceViewSelectCallback

    Protected Overrides Sub PerformDataBinding(ByVal retrievedData As IEnumerable)
        MyBase.PerformDataBinding(retrievedData)

        ' If the data is retrieved from an IDataSource as an IEnumerable 
        ' collection, attempt to bind its values to a set of TextBox controls.
        If Not (retrievedData Is Nothing) Then

            Dim dataItem As Object
            For Each dataItem In retrievedData

                Dim box As New TextBox()

                ' The dataItem is not just a string, but potentially
                ' a System.Data.DataRowView or some other container. 
                ' If DataTextField is set, use it to determine which 
                ' field to render. Otherwise, use the first field.                    
                If DataTextField.Length > 0 Then
                    box.Text = DataBinder.GetPropertyValue( _
                    dataItem, DataTextField, Nothing)
                Else
                    Dim props As PropertyDescriptorCollection = _
                        TypeDescriptor.GetProperties(dataItem)

                    ' Set the "default" value of the TextBox.
                    box.Text = String.Empty

                    ' Set the true data-bound value of the TextBox,
                    ' if possible.
                    If props.Count >= 1 Then
                        If props(0).GetValue(dataItem) IsNot Nothing Then
                            box.Text = props(0).GetValue(dataItem).ToString()
                        End If
                    End If
                End If

                BoxSet.Add(box)
            Next dataItem
        End If

    End Sub 'PerformDataBinding

    Protected Overrides Sub Render(ByVal writer As HtmlTextWriter)

        ' Render nothing if the control is empty.            
        If BoxSet.Count <= 0 Then
            Return
        End If

        ' Make sure the control is declared in a form tag with runat=server.
        If Not (Page Is Nothing) Then
            Page.VerifyRenderingInServerForm(Me)
        End If

        ' For this example, render the BoxSet as 
        ' an unordered list of TextBox controls.            
        writer.RenderBeginTag(HtmlTextWriterTag.Ul)

        Dim item As Object
        For Each item In BoxSet

            Dim box As TextBox = CType(item, TextBox)

            ' Write each element as 
            ' <li><input type="text" value="string"><input/></li>
            writer.WriteBeginTag("li")
            writer.Write(">")
            writer.WriteBeginTag("input")
            writer.WriteAttribute("type", "text")
            writer.WriteAttribute("value", box.Text)
            writer.Write(">")
            writer.WriteEndTag("input")
            writer.WriteEndTag("li")
        Next item

        writer.RenderEndTag()

    End Sub 'Render
    End Class 'TextBoxSet 
End Namespace

using System;
using System.Collections;
using System.ComponentModel;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace Samples.AspNet.Controls.CS {

    [AspNetHostingPermission(SecurityAction.Demand, 
        Level=AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, 
        Level=AspNetHostingPermissionLevel.Minimal)]
    public class TextBoxSet : DataBoundControl {

        private IList alBoxSet;
        public IList BoxSet {
            get {
                if (null == alBoxSet) {
                     alBoxSet = new ArrayList();
                }
                return alBoxSet;                
            }                    
        }
        public string DataTextField {
            get {
                object o = ViewState["DataTextField"];
                return((o == null) ? string.Empty : (string)o);
            }
            set {
                ViewState["DataTextField"] = value;
                if (Initialized) {
                    OnDataPropertyChanged();
                }
            }
        }
        protected override void PerformSelect() {            

           // Call OnDataBinding here if bound to a data source using the
           // DataSource property (instead of a DataSourceID), because the
           // databinding statement is evaluated before the call to GetData.       
            if (! IsBoundUsingDataSourceID) {
                OnDataBinding(EventArgs.Empty);
            }            

            // The GetData method retrieves the DataSourceView object from  
            // the IDataSource associated with the data-bound control.            
            GetData().Select(CreateDataSourceSelectArguments(), 
                OnDataSourceViewSelectCallback);

            // The PerformDataBinding method has completed.
            RequiresDataBinding = false;
            MarkAsDataBound();

            // Raise the DataBound event.
            OnDataBound(EventArgs.Empty);
        }
        private void OnDataSourceViewSelectCallback(IEnumerable retrievedData) {

           // Call OnDataBinding only if it has not already been 
           // called in the PerformSelect method.
            if (IsBoundUsingDataSourceID) {
                OnDataBinding(EventArgs.Empty);
            }
            // The PerformDataBinding method binds the data in the  
            // retrievedData collection to elements of the data-bound control.
            PerformDataBinding(retrievedData);                                    
        }
        protected override void PerformDataBinding(IEnumerable retrievedData) {
            base.PerformDataBinding(retrievedData);

            // If the data is retrieved from an IDataSource as an 
            // IEnumerable collection, attempt to bind its values to a 
            // set of TextBox controls.
            if (retrievedData != null) {

                foreach (object dataItem in retrievedData) {

                    TextBox box = new TextBox();

                    // The dataItem is not just a string, but potentially
                    // a System.Data.DataRowView or some other container. 
                    // If DataTextField is set, use it to determine which 
                    // field to render. Otherwise, use the first field.                    
                    if (DataTextField.Length > 0) {
                        box.Text = DataBinder.GetPropertyValue(dataItem, 
                            DataTextField, null);
                    }
                    else {
                        PropertyDescriptorCollection props = 
                            TypeDescriptor.GetProperties(dataItem);

                        // Set the "default" value of the TextBox.
                        box.Text = String.Empty;

                        // Set the true data-bound value of the TextBox,
                        // if possible.
                        if (props.Count >= 1) {                        
                            if (null != props[0].GetValue(dataItem)) {
                                box.Text = props[0].GetValue(dataItem).ToString();
                            }
                        }
                    }                                        

                    BoxSet.Add(box);
                }
            }
        }
        protected override void Render(HtmlTextWriter writer) {

            // Render nothing if the control is empty.            
            if (BoxSet.Count <= 0) {
                return;
            }

            // Make sure the control is declared in a form tag 
            // with runat=server.
            if (Page != null) {
                Page.VerifyRenderingInServerForm(this);
            }

            // For this example, render the BoxSet as 
            // an unordered list of TextBox controls.            
            writer.RenderBeginTag(HtmlTextWriterTag.Ul);

            foreach (object item in BoxSet) {

                TextBox box = (TextBox) item;

                // Write each element as 
                // <li><input type="text" value="string"><input/></li>

                writer.WriteBeginTag("li");
                writer.Write(">");
                writer.WriteBeginTag("input");
                writer.WriteAttribute("type", "text");
                writer.WriteAttribute("value", box.Text);
                writer.Write(">");
                writer.WriteEndTag("input");
                writer.WriteEndTag("li");
            }            

            writer.RenderEndTag();                       
        }
    }
}

<%@Page language="VB" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.Controls.VB" 
    Assembly="Samples.AspNet.Controls.VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
  <head>
    <title>TextBoxSet Data-Bound Control - VB Example</title>
  </head>

  <body>
    <form id="Form1" method="post" runat="server">

        <aspSample:textboxset
          id="TextBoxSet1"
          runat="server"
          datasourceid="AccessDataSource1" />

        <asp:accessdatasource
          id="AccessDataSource1"
          runat="server"
          datafile="Northwind.mdb"
          selectcommand="SELECT lastname FROM Employees" />

    </form>
  </body>
</html>

<%@Page language="c#" %>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.Controls.CS" 
    Assembly="Samples.AspNet.Controls.CS" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
  <head>
    <title>TextBoxSet Data-Bound Control  - C# Example</title>
  </head>

  <body>
    <form id="Form1" method="post" runat="server">

        <aspSample:textboxset
          id="TextBoxSet1"
          runat="server"
          datasourceid="AccessDataSource1" />

        <asp:accessdatasource
          id="AccessDataSource1"
          runat="server"
          datafile="Northwind.mdb"
          selectcommand="SELECT lastname FROM Employees" />

    </form>
  </body>
</html>