Programming Microsoft Visual Basic .NET/Programming Microsoft Visual Basic .NET (Microsoft Press)(X08-78517)(2002).bin/setup/vbnet/23 web forms and controls/firstwebforms/listcontrolsform.aspx.vb

Text File | 2002-03-17 | 5.8 KB | 140 lines

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.SqlClient

' This form demonstrates how to leverage several features
' of List controls

Public Class ListControlsForm
    Inherits System.Web.UI.Page
    Protected WithEvents lstPublishers As System.Web.UI.WebControls.ListBox
    Protected WithEvents lblListBoxInfo As System.Web.UI.WebControls.Label
    Protected WithEvents cblContinents As System.Web.UI.WebControls.CheckBoxList
    Protected WithEvents rblWeekdays As System.Web.UI.WebControls.RadioButtonList
    Protected WithEvents lblDropDownListInfo As System.Web.UI.WebControls.Label
    Protected WithEvents lblCheckBoxListInfo As System.Web.UI.WebControls.Label
    Protected WithEvents lblRadioButtonListInfo As System.Web.UI.WebControls.Label
    Protected WithEvents ddlColors As System.Web.UI.WebControls.DropDownList

#Region " Web Form Designer Generated Code "

    'This call is required by the Web Form Designer.
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

    End Sub

    Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
        'CODEGEN: This method call is required by the Web Form Designer
        'Do not modify it using the code editor.
        InitializeComponent()
    End Sub

#End Region

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here

        If Not Page.IsPostBack Then
            ' Fill a string array with the names of all known colors.
            Dim colors() As String = [Enum].GetNames(GetType(System.Drawing.KnownColor))
            ' Bind it to the ddlColors dropdownlist control.
            ddlColors.DataSource = colors

#Const USE_DATATEXTFORMATSTRING = False

#If USE_DATATEXTFORMATSTRING = False Then
            ' Open a connection to Biblio.mdb and create a DataReader.
            Dim cn As New OleDbConnection(BiblioConnString)
            Dim cmd As New OleDbCommand("SELECT PubId,Name FROM Publishers", cn)
            cn.Open()
            Dim dr As OleDbDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            ' Bind the DataReader to the ListBox control.
            lstPublishers.DataSource = dr
            lstPublishers.DataTextField = "Name"
            lstPublishers.DataValueField = "PubId"
#Else
            ' Open a connection to Pubs and create a DataReader.
            Dim cn As New OleDbConnection(OledbPubsConnString)
            Dim cmd As New OleDbCommand("SELECT * FROM Titles", cn)
            cn.Open()
            Dim dr As OleDbDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
            ' Bind the DataReader to the ListBox control.
            lstPublishers.DataSource = dr
            lstPublishers.DataTextField = "pubdate"
            lstPublishers.DataValueField = "title_id"
            lstPublishers.DataTextFormatString = "{0:D}"
#End If

            ' Creating the collection of radio buttons via code.
            Dim i As Integer
            For i = 1 To 7
                Dim li As New ListItem(WeekdayName(i), i.ToString)
                rblWeekdays.Items.Add(li)
            Next

            ' Create a HashTable with continent names.
            Dim continents As New Hashtable(5)
            continents.Add("America", 1)
            continents.Add("Europa", 2)
            continents.Add("Asia", 3)
            continents.Add("Africa", 4)
            continents.Add("Australia", 5)

            ' Bind it to the cblContinents CheckBoxList control.
            cblContinents.DataSource = continents
            cblContinents.DataTextField = "Key"
            cblContinents.DataValueField = "Value"

            ' Perform binding for all the controls in the page.
            Me.DataBind()

            ' Close the DataReader (and the Connection.)
            dr.Close()
        End If

    End Sub

    ' a new item in the multiselect ListBox control has been selected

    Private Sub lstPublishers_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstPublishers.SelectedIndexChanged
        Dim li As ListItem, msg As String
        ' check the Selected property of each element in the list
        For Each li In lstPublishers.Items
            If li.Selected Then
                msg &= String.Format("Item = {0}, Value = {1} <br>", li.Text, li.Value)
            End If
        Next
        lblListBoxInfo.Text = msg
    End Sub

    ' an element of the DropDownList control has been selected

    Private Sub ddlColors_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ddlColors.SelectedIndexChanged
        With ddlColors.SelectedItem
            lblDropDownListInfo.Text = "Item = " & .Text & ", Value = " & .Value
        End With
    End Sub

    ' an element of the RadioButtonList control has been selected

    Private Sub rblWeekdays_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles rblWeekdays.SelectedIndexChanged
        With rblWeekdays.SelectedItem
            lblRadioButtonListInfo.Text = "Item = " & .Text & ", Value = " & .Value
        End With
    End Sub

    ' an element of the CheckBoxList control has been selected

    Private Sub cblContinents_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cblContinents.SelectedIndexChanged
        Dim li As ListItem, msg As String
        ' check the Selected property of each item
        For Each li In cblContinents.Items
            If li.Selected Then
                msg &= String.Format("Item = {0}, Value = {1}<br>", li.Text, li.Value)
            End If
        Next
        lblCheckBoxListInfo.Text = msg
    End Sub

End Class