I am currently working on a page that has a user control that builds a dynamic table. The control is originally loaded on the Page_Init event, and any time that an event is raised that changes the dynamic control the table is reloaded. The problem here is that if the control is changed between between loads, the events from the control do not fire. For instance, there are originally two rows in the table. An item is added to the table during the postback and now there are four rows (this table adds two rows at a time). Each row has one or two buttons. When the page is loaded and sent back to the browser, if a user clicks on any of the buttons, a postback occurs, but the event does not fire. What am I doing wrong here? How can I tell what control/event caused the postback? Below is the code for both the page, and the user control.
Payments.aspx:
Partial Public Class Payments
Inherits BasePage
Private foodMaster As Food
Private _check As BusinessLayer.CustomerCheck
Private Sub btnAddCheck_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAddCheck.Click
' do nothing. the modal window is tied to the button via the modal window in the designer
End Sub
Private Sub btnCalendar_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles btnCalendar.Click
calCheckDate.Visible = Not calCheckDate.Visible
modCheck.Show()
End Sub
Private Sub btnCheckSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCheckSave.Click
Try
If IsNothing(_check) Then _check = New BusinessLayer.CustomerCheck
If Me.CurrentCheck > 0 Then _check.CheckId = Me.CurrentCheck
_check.CheckNumber = txtCheckNumber.Text
_check.CheckDate = CDate(txtCheckDate.Text)
_check.CheckAmount = CDbl(txtCheckAmount.Text)
_check.DepositId = Me.CurrentDeposit
_check.Save()
LoadControls()
' reset the current check to not get confused after an edit
Me.CurrentCheck = 0
SetupNewCheck()
Catch ex As Exception
lblMessage.Text = "Could not save check."
lblMessage.Visible = True
modCheck.Show()
End Try
End Sub
Private Sub calCheckDate_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles calCheckDate.SelectionChanged
txtCheckDate.Text = calCheckDate.SelectedDate.ToShortDateString()
calCheckDate.Visible = False
modCheck.Show()
End Sub
Private Sub cvFutureDate_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles cvFutureDate.ServerValidate
Try
Dim depositDate As DateTime = DateTime.Parse(txtCheckDate.Text)
Dim futureDate As DateTime = Now.AddDays(1)
Dim tomorrow As New DateTime(futureDate.Year, futureDate.Month, futureDate.Day)
args.IsValid = CBool(depositDate < tomorrow)
Catch
args.IsValid = False
End Try
End Sub
Private Sub cvInvalidAmount_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles cvInvalidAmount.ServerValidate
Try
Double.Parse(txtCheckAmount.Text)
Catch
args.IsValid = False
End Try
End Sub
Private Sub cvInvalidDate_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles cvInvalidDate.ServerValidate
Try
DateTime.Parse(txtCheckDate.Text)
Catch
args.IsValid = False
End Try
End Sub
Private Sub DepositEditing()
foodMaster.Deposit.Load(Me.CurrentDeposit)
foodMaster.ShowDepositWindow()
End Sub
Private Sub DepositSaved()
dihHeader.Deposit.Load(Me.CurrentDeposit)
dihHeader.Reload()
End Sub
Private Sub Payments_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
LoadControls()
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
foodMaster = DirectCast(Me.Master, Food)
AddHandler foodMaster.SaveClicked, AddressOf DepositSaved
AddHandler foodMaster.EditButtonClicked, AddressOf DepositEditing
If IsPostBack = False Then
Me.CurrentCheck = 0
SetupNewCheck()
End If
End Sub
Private Sub pcPayments_ApplyFundsClicked(ByVal CheckId As Integer) Handles pcPayments.ApplyFundsClicked
End Sub
Private Sub pcPayments_DeleteClicked(ByVal CheckId As Integer) Handles pcPayments.DeleteClicked
Try
If Me.CurrentCheck = CheckId Then Me.CurrentCheck = 0
_check = New BusinessLayer.CustomerCheck
_check.CheckId = CheckId
_check.DeleteAllPayments()
_check.Delete()
LoadControls()
Catch
End Try
End Sub
Private Sub pcPayments_EditClicked(ByVal CheckId As Integer) Handles pcPayments.EditClicked
Me.CurrentCheck = CheckId
_check = New BusinessLayer.CustomerCheck(CheckId)
txtCheckAmount.Text = _check.CheckAmount.ToString("0.00")
txtCheckDate.Text = _check.CheckDate.ToShortDateString
calCheckDate.SelectedDate = _check.CheckDate
txtCheckNumber.Text = _check.CheckNumber
modCheck.Show()
End Sub
Private Sub LoadControls()
Dim checks As New BusinessLayer.CustomerCheckCollection()
checks.LoadByDeposit(Me.CurrentDeposit)
pcPayments.Checks = checks
pcPayments.Reload()
dihHeader.Deposit.Load(Me.CurrentDeposit)
dihHeader.TotalCheckAmount = pcPayments.TotalCheckAmount
dihHeader.TotalAppliedAmount = pcPayments.TotalAmountApplied
dihHeader.Reload()
End Sub
Private Sub SetupNewCheck()
_check = Nothing
txtCheckDate.Text = Now.ToShortDateString()
calCheckDate.SelectedDate = Now
txtCheckAmount.Text = String.Empty
txtCheckNumber.Text = String.Empty
End Sub
End Class
PaymentsControl.ascx
Public Partial Class PaymentsControl
Inherits System.Web.UI.UserControl
Private _checks As BusinessLayer.CustomerCheckCollection
Private _applied As Double
Public Event ApplyFundsClicked(ByVal CheckId As Integer)
Public Event DeleteClicked(ByVal CheckId As Integer)
Public Event EditClicked(ByVal CheckId As Integer)
Public Sub New()
_checks = New BusinessLayer.CustomerCheckCollection
_applied = 0
End Sub
Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'If IsPostBack = False Then
' BindChecks()
'End If
End Sub
Private Sub ApplyButtonClicked(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent ApplyFundsClicked(DirectCast(sender, LinkButton).CommandArgument)
End Sub
Private Sub DeleteButtonClicked(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs)
RaiseEvent DeleteClicked(DirectCast(sender, ImageButton).CommandArgument)
End Sub
Private Sub EditButtonClicked(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs)
RaiseEvent EditClicked(DirectCast(sender, ImageButton).CommandArgument)
End Sub
Private Sub BindChecks()
tblChecks.Rows.Clear()
tblChecks.Rows.Add(BuildTableHeader())
_applied = 0
For i As Int16 = 0 To _checks.Count - 1
_checks(i).LoadAllPayments()
_applied += _checks(i).TotalAmountApplied
tblChecks.Rows.Add(BuildCheckRow(_checks(i)))
tblChecks.Rows.Add(BuildInvoiceRow(_checks(i)))
Next
If tblChecks.Rows.Count = 1 Then tblChecks.Visible = False
End Sub
Private Function BuildCheckRow(ByVal Check As BusinessLayer.CustomerCheck) As TableRow
Dim checkNumberCell As New TableCell()
Dim checkDateCell As New TableCell()
Dim checkAmountCell As New TableCell()
Dim totalAppliedCell As New TableCell()
checkNumberCell.Text = Check.CheckNumber
checkDateCell.Text = Check.CheckDate.ToShortDateString()
checkAmountCell.Text = Check.CheckAmount.ToString("C")
totalAppliedCell.Text = Check.TotalAmountApplied.ToString("C")
If Check.TotalAmountApplied <> Check.CheckAmount Then totalAppliedCell.ForeColor = Drawing.Color.Red
Dim myRow As New TableRow
myRow.Cells.Add(BuildCheckControlCell(Check.CheckId))
myRow.Cells.Add(checkNumberCell)
myRow.Cells.Add(checkDateCell)
myRow.Cells.Add(checkAmountCell)
myRow.Cells.Add(totalAppliedCell)
Return myRow
End Function
Private Function BuildCheckControlCell(ByVal CheckId As Integer) As TableCell
Dim editButton As New ImageButton()
editButton.CommandArgument = CheckId
editButton.CausesValidation = False
editButton.AlternateText = "Edit"
editButton.ImageUrl = "~/images/icons/bullet_edit.png"
AddHandler editButton.Click, AddressOf EditButtonClicked
Dim deleteButton As New ImageButton
deleteButton.CommandArgument = CheckId
deleteButton.CausesValidation = False
deleteButton.AlternateText = "Delete"
deleteButton.ImageUrl = "~/images/icons/bullet_cross.png"
deleteButton.Attributes.Add("onclick", "return confirmDelete()")
AddHandler deleteButton.Click, AddressOf DeleteButtonClicked
Dim blankSpace As New Literal()
blankSpace.Text = " "
Dim myCell As New TableCell
myCell.Controls.Add(editButton)
myCell.Controls.Add(blankSpace)
myCell.Controls.Add(deleteButton)
Return myCell
End Function
Private Function BuildInvoiceRow(ByVal Check As BusinessLayer.CustomerCheck) As TableRow
Dim invoiceDetailCell As New TableCell
invoiceDetailCell.ColumnSpan = 4
invoiceDetailCell.Controls.Add(BuildInvoiceDetailTable(Check.Payments))
Dim myRow As New TableRow
myRow.Cells.Add(BuildInvoiceControlCell(Check.CheckId))
myRow.Cells.Add(invoiceDetailCell)
Return myRow
End Function
Private Function BuildInvoiceControlCell(ByVal CheckId As Integer) As TableCell
Dim text As New Literal
text.Text = "Invoices for check:<br />"
Dim applyButton As New LinkButton
applyButton.CommandArgument = CheckId
applyButton.CausesValidation = False
applyButton.Text = "Apply Funds"
AddHandler applyButton.Click, AddressOf ApplyButtonClicked
Dim myCell As New TableCell
myCell.Controls.Add(text)
myCell.Controls.Add(applyButton)
Return myCell
End Function
Private Function BuildInvoiceDetailTable(ByVal Payments As BusinessLayer.PaymentTransactionCollection) As Table
Dim myTable As New Table
myTable.CssClass = "tableSub"
myTable.CellPadding = "0"
myTable.CellSpacing = "0"
myTable.BorderWidth = "0"
myTable.Rows.Add(BuildInvoiceDetailHeader())
For i As Integer = 0 To Payments.Count - 1
myTable.Rows.Add(BuildPaymentRow(Payments(i)))
Next
If myTable.Rows.Count = 1 Then myTable.Visible = False
Return myTable
End Function
Private Function BuildInvoiceDetailHeader() As TableRow
Dim customerCell As New TableHeaderCell
Dim invoiceCell As New TableHeaderCell
Dim dueCell As New TableHeaderCell
Dim paymentCell As New TableHeaderCell
customerCell.Text = "Customer"
invoiceCell.Text = "Invoice number"
dueCell.Text = "Amount due"
paymentCell.Text = "Payment amount"
Dim myRow As New TableRow
myRow.Cells.Add(customerCell)
myRow.Cells.Add(invoiceCell)
myRow.Cells.Add(dueCell)
myRow.Cells.Add(paymentCell)
Return myRow
End Function
Private Function BuildPaymentRow(ByVal Payment As BusinessLayer.PaymentTransaction) As TableRow
Dim customerCell As New TableCell
Dim invoiceCell As New TableCell
Dim amountDueCell As New TableCell
Dim paymentCell As New TableCell
'Payment.Customer.Load()
customerCell.Text = Payment.Customer.NumberAndName
invoiceCell.Text = Payment.Invoice.InvoiceNumber
amountDueCell.Text = Payment.Invoice.AmountDue.ToString("C")
paymentCell.Text = Payment.PaymentAmount.ToString("C")
Dim myRow As New TableRow
myRow.Cells.Add(customerCell)
myRow.Cells.Add(invoiceCell)
myRow.Cells.Add(amountDueCell)
myRow.Cells.Add(paymentCell)
Return myRow
End Function
Private Function BuildTableHeader() As TableRow
Dim blankCell As New TableHeaderCell()
Dim checkNumberCell As New TableHeaderCell()
Dim checkDateCell As New TableHeaderCell()
Dim checkAmountCell As New TableHeaderCell()
Dim totalUnappliedCell As New TableHeaderCell()
checkNumberCell.Text = "Check number"
checkDateCell.Text = "Check date"
checkAmountCell.Text = "Check amount"
totalUnappliedCell.Text = "Total unapplied"
Dim myRow As New TableRow
myRow.Cells.Add(blankCell)
myRow.Cells.Add(checkNumberCell)
myRow.Cells.Add(checkDateCell)
myRow.Cells.Add(checkAmountCell)
myRow.Cells.Add(totalUnappliedCell)
Return myRow
End Function
Public Sub Reload()
BindChecks()
End Sub
Public Property Checks() As BusinessLayer.CustomerCheckCollection
Get
Return _checks
End Get
Set(ByVal value As BusinessLayer.CustomerCheckCollection)
_checks = value
End Set
End Property
Public ReadOnly Property TotalCheckAmount() As Double
Get
Return _checks.TotalCheckAmount
End Get
End Property
Public ReadOnly Property TotalAmountApplied() As Double
Get
Return _applied
End Get
End Property
End Class
You need to assign the Id property to each dynamically added server control that will serve up postback events. Also, on postback, I believe that the dynamically added controls need to be recreated with the same id in order for postback methods and viewstate to function correctly.
Related
I have a timer i press a button to start it and press a button to stop it but the button used to stop the timer does not work, i tried dispose,stop and enabled=false,all of them did not worked.The timer continues to send telegram messages even though i pressed stop. Frontend is a aspx form.
Dim aTimer As New System.Timers.Timer
Public Function TelegramSendMessage(ByVal apilToken As String, ByVal destID As String, ByVal text As String) As String
Dim a As String = apilToken
Dim urlString As String = "https://api.telegram.org/bot" + apilToken + "/sendMessage?chat_id=" + destID + "&text=" + text
Dim webclient As WebClient = New WebClient()
Return webclient.DownloadString(urlString)
End Function
Private Sub tick(ByVal sender As Object, ByVal e As System.Timers.ElapsedEventArgs)
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
TelegramSendMessage(yourtoken,destinationid , "hi")
End Sub
Protected Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
aTimer.AutoReset = True
aTimer.Interval = 60000
AddHandler aTimer.Elapsed, AddressOf tick
aTimer.Enabled = True
End Sub
Protected Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
'aTimer.Dispose()
'aTimer.Enabled = False
aTimer.Stop()
End Sub
i need help with following code.its works well..but when page is loading it show all data from database and user can choose from them whichone rows he want to delete..
i want to use some kind of filter.
i mean.when page is loading,,its empty..i just input text in textbox and then click search button and all rows that contains specific text from textbox are diplayed..now i choose that rows i want to delete and mark them by checkbox to delete.
in easy words...i want to choose from specific rows that containts textbox text and mark them to delete...not from all rows ...
thank you all for any help
that my code
Imports System
Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports System.Collections
Imports System.Text
Partial Public Class VB
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
If IsPostBack Then
GetData()
End If
BindGrid()
End Sub
Private Sub BindGrid()
Dim constr As String = ConfigurationManager _
.ConnectionStrings("conString").ConnectionString()
Dim query As String = "select * from TestCustomers"
Dim con As New SqlConnection(constr)
Dim sda As New SqlDataAdapter(query, con)
Dim dt As New DataTable()
sda.Fill(dt)
gvAll.DataSource = dt
gvAll.DataBind()
End Sub
Protected Sub OnPaging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)
gvAll.PageIndex = e.NewPageIndex
gvAll.DataBind()
SetData()
End Sub
Private Sub GetData()
Dim arr As ArrayList
If ViewState("SelectedRecords") IsNot Nothing Then
arr = DirectCast(ViewState("SelectedRecords"), ArrayList)
Else
arr = New ArrayList()
End If
Dim chkAll As CheckBox = DirectCast(gvAll.HeaderRow _
.Cells(0).FindControl("chkAll"), CheckBox)
For i As Integer = 0 To gvAll.Rows.Count - 1
If chkAll.Checked Then
If Not arr.Contains(gvAll.DataKeys(i).Value) Then
arr.Add(gvAll.DataKeys(i).Value)
End If
Else
Dim chk As CheckBox = DirectCast(gvAll.Rows(i).Cells(0) _
.FindControl("chk"), CheckBox)
If chk.Checked Then
If Not arr.Contains(gvAll.DataKeys(i).Value) Then
arr.Add(gvAll.DataKeys(i).Value)
End If
Else
If arr.Contains(gvAll.DataKeys(i).Value) Then
arr.Remove(gvAll.DataKeys(i).Value)
End If
End If
End If
Next
ViewState("SelectedRecords") = arr
End Sub
Private Sub SetData()
Dim currentCount As Integer = 0
Dim chkAll As CheckBox = DirectCast(gvAll.HeaderRow _
.Cells(0).FindControl("chkAll"), CheckBox)
chkAll.Checked = True
Dim arr As ArrayList = DirectCast(ViewState("SelectedRecords") _
, ArrayList)
For i As Integer = 0 To gvAll.Rows.Count - 1
Dim chk As CheckBox = DirectCast(gvAll.Rows(i).Cells(0) _
.FindControl("chk"), CheckBox)
If chk IsNot Nothing Then
chk.Checked = arr.Contains(gvAll.DataKeys(i).Value)
If Not chk.Checked Then
chkAll.Checked = False
Else
currentCount += 1
End If
End If
Next
hfCount.Value = (arr.Count - currentCount).ToString()
End Sub
Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As EventArgs)
Dim count As Integer = 0
SetData()
gvAll.AllowPaging = False
gvAll.DataBind()
Dim arr As ArrayList = DirectCast(ViewState("SelectedRecords") _
, ArrayList)
count = arr.Count
For i As Integer = 0 To gvAll.Rows.Count - 1
If arr.Contains(gvAll.DataKeys(i).Value) Then
DeleteRecord(gvAll.DataKeys(i).Value.ToString())
arr.Remove(gvAll.DataKeys(i).Value)
End If
Next
ViewState("SelectedRecords") = arr
hfCount.Value = "0"
gvAll.AllowPaging = True
BindGrid()
ShowMessage(count)
End Sub
Private Sub DeleteRecord(ByVal CustomerID As String)
Dim constr As String = ConfigurationManager _
.ConnectionStrings("conString").ConnectionString
Dim query As String = "delete from TestCustomers where" & _
" CustomerID=#CustomerID"
Dim con As New SqlConnection(constr)
Dim cmd As New SqlCommand(query, con)
cmd.Parameters.AddWithValue("#CustomerID", CustomerID)
con.Open()
cmd.ExecuteNonQuery()
con.Close()
End Sub
Private Sub ShowMessage(ByVal count As Integer)
Dim sb As New StringBuilder()
sb.Append("<script type = 'text/javascript'>")
sb.Append("alert('")
sb.Append(count.ToString())
sb.Append(" records deleted.');")
sb.Append("</script>")
ClientScript.RegisterStartupScript(Me.GetType(), _
"script", sb.ToString())
End Sub
End Class
You just have to modify your SQL query. It is selecting all fields without any where condition. Let's assume you have two fields A and B in which you want to search for the text. Then your query should change to
Select * from TestCustomers where A like '%"+TextBox1.Text+"%' or B like '%"+TextBox1.Text+"%'
I am completely new to ASP.NET and VB as well as C#. I am trying to add customers to a contact list out of a DB. Then the list can be referenced to call them up.
But when I try to run it I get System.NullReferenceException: Object reference not set to an instance of an object. In line 19.
Here is my code:
Page 1 is default page...it connects to the database and grabs the contact information and allows me to select the current contact and add them to a listbox on a separate page:
Imports System.Data
Partial Class _Default
Inherits System.Web.UI.Page
Private SelectedCustomer As Customer
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles Me.Load
If Not IsPostBack Then
ddlCustomers.DataBind()
End If
SelectedCustomer = Me.GetSelectedCustomer
Me.DisplayCustomer()
End Sub
Private Function GetSelectedCustomer() As Customer
Dim dvTable As dataview = CType(AccessDataSource1.Select( _
DataSourceSelectArguments.Empty), dataview)
dvTable.RowFilter = "CustomerID = " & ddlCustomers.SelectedValue
Dim drvRow As DataRowView = dvTable(0)
Dim customer As New Customer
customer.CustomerID = CInt(drvRow("CustomerID"))
customer.Name = drvRow("Name").ToString
customer.Address = drvRow("Address").ToString
customer.City = drvRow("City").ToString
customer.State = drvRow("State").ToString
customer.ZipCode = drvRow("ZipCode").ToString
customer.Phone = drvRow("Phone").ToString
customer.Email = drvRow("Email").ToString
Return customer
End Function
Private Sub DisplayCustomer()
lblAddress.Text = SelectedCustomer.Address
lblCityStateZip.Text = SelectedCustomer.City & ", " _
& SelectedCustomer.State & " " _
& SelectedCustomer.ZipCode
lblPhone.Text = SelectedCustomer.Phone
lblEmail.Text = SelectedCustomer.Email
End Sub
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click
If Page.IsValid Then
Dim customerItem As New Customer
customerItem.Name = SelectedCustomer.ToString
Me.AddToCustomer(customerItem)
Response.Redirect("CustomerList.aspx")
End If
End Sub
Private Sub AddToCustomer(ByVal customerItem As Customer)
Dim customer As SortedList = Me.GetCustomer
Dim customerID As String = SelectedCustomer.CustomerID
If customer.ContainsKey(customerID) Then
customerItem = CType(customer(customerID), Customer)
Else
customer.Add(customerID, customerItem)
End If
End Sub
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Customer"), SortedList)
End Function
End Class
The next bit of code allows me to add the contact to a list box:
Partial Class Default2
Inherits System.Web.UI.Page
Private Customer As SortedList
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Customer = Me.GetCustomer
If Not IsPostBack Then Me.DisplayCustomer()
End Sub
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Cart"), SortedList)
End Function
Private Sub DisplayCustomer()
lstCustomer.Items.Clear()
Dim customerItem As Customer
For Each customerEntry As DictionaryEntry In Customer
customerItem = CType(customerEntry.Value, Customer)
lstCustomer.Items.Add(customerItem.Name)
Next
End Sub
Protected Sub lstCustomer_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstCustomer.SelectedIndexChanged
End Sub
End Class
The error occurs on line 19 (For Each customerEntry As DictionaryEntry In Customer) in the second set of code from the default2 class. Any ideas? I am completely new to ASP.NET just trying to learn. I more at home on PHP, Java, and Actionscript unfortunately.
I think the problem is in this function
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Cart"), SortedList)
End Function
You initialise Customer here but then pull out of Session("Cart")
I think what you meant to do is
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Customer"), SortedList)
End Function
Now customer should always be initialised whereas before it might not have been which would cause the NullReferenceException that you are getting.
For some reason my code is not adding customer to the session. I am new to ASP.NET does anyone have any input as to why this is happening and maybe able to give some code example. Thanks!
Below it the code.
Imports System.Data
Partial Class _Default
Inherits System.Web.UI.Page
Private SelectedCustomer As Customer
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles Me.Load
If Not IsPostBack Then
ddlCustomers.DataBind()
End If
SelectedCustomer = Me.GetSelectedCustomer
Me.DisplayCustomer()
End Sub
Private Function GetSelectedCustomer() As Customer
Dim dvTable As dataview = CType(AccessDataSource1.Select( _
DataSourceSelectArguments.Empty), dataview)
dvTable.RowFilter = "CustomerID = " & ddlCustomers.SelectedValue
Dim drvRow As DataRowView = dvTable(0)
Dim customer As New Customer
customer.CustomerID = CInt(drvRow("CustomerID"))
customer.Name = drvRow("Name").ToString
customer.Address = drvRow("Address").ToString
customer.City = drvRow("City").ToString
customer.State = drvRow("State").ToString
customer.ZipCode = drvRow("ZipCode").ToString
customer.Phone = drvRow("Phone").ToString
customer.Email = drvRow("Email").ToString
Return customer
End Function
Private Sub DisplayCustomer()
lblAddress.Text = SelectedCustomer.Address
lblCityStateZip.Text = SelectedCustomer.City & ", " _
& SelectedCustomer.State & " " _
& SelectedCustomer.ZipCode
lblPhone.Text = SelectedCustomer.Phone
lblEmail.Text = SelectedCustomer.Email
End Sub
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click
If Page.IsValid Then
Dim customerItem As New Customer
customerItem.Name = SelectedCustomer.ToString
Me.AddToCustomer(customerItem)
Response.Redirect("CustomerList.aspx")
End If
End Sub
Private Sub AddToCustomer(ByVal customerItem As Customer)
Dim customer As SortedList = Me.GetCustomer
Dim customerID As String = SelectedCustomer.CustomerID
If customer.ContainsKey(customerID) Then
customerItem = CType(customer(customerID), Customer)
Else
customer.Add(customerID, customerItem)
End If
End Sub
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Customer"), SortedList)
End Function
End Class
Second page of code below:
Partial Class Default2
Inherits System.Web.UI.Page
Private Customer As SortedList
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Customer = Me.GetCustomer
If Not IsPostBack Then Me.DisplayCustomer()
End Sub
Private Function GetCustomer() As SortedList
If Session("Customer") Is Nothing Then
Session.Add("Customer", New SortedList)
End If
Return CType(Session("Customer"), SortedList)
End Function
Private Sub DisplayCustomer()
lstCustomer.Items.Clear()
Dim customerItem As Customer
For Each customerEntry As DictionaryEntry In Customer
customerItem = CType(customerEntry.Value, Customer)
lstCustomer.Items.Add(customerItem.Name)
Next
End Sub
Protected Sub lstCustomer_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles lstCustomer.SelectedIndexChanged
End Sub
Protected Sub Clearbtn_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Clearbtn.Click
If Customer.Count > 0 Then
Customer.Clear()
lstCustomer.Items.Clear()
Else
clrErr.Text = "ERROR: NO CUSTOMERS STORED"
End If
End Sub
End Class
I think I've actually answered this in another of your questions
You need to add a line to actually store the updated customer object back into Session for example
Private Sub AddToCustomer(ByVal customerItem As Customer)
Dim customer As SortedList = Me.GetCustomer
Dim customerID As String = SelectedCustomer.CustomerID
If customer.ContainsKey(customerID) Then
customerItem = CType(customer(customerID), Customer)
Else
customer.Add(customerID, customerItem)
End If
Session("Customer") = customer
End Sub
Although I'd recommend you put this in another function so that your design doesn't depend on Session if you want to change it later on. So more like
Private Sub AddToCustomer(ByVal customerItem As Customer)
Dim customer As SortedList = Me.GetCustomer
Dim customerID As String = SelectedCustomer.CustomerID
If customer.ContainsKey(customerID) Then
customerItem = CType(customer(customerID), Customer)
Else
customer.Add(customerID, customerItem)
End If
StoreCustomer(customer)
End Sub
Private Sub StoreCustomer(ByVal customer As SortedList)
Session("Customer") = customer
End Sub
At the moment all local changes to customer are lost just after the call toto AddToCustomer as you then do a redirect after.
Me.AddToCustomer(customerItem)
Response.Redirect("CustomerList.aspx")
I extended treeview, treenode, and nodetype so I could have custom nodes. Certain nodes have image buttons on them allowing them to add a child node or delete the node. I can't handle any of the events from my buttons.
Public Class ContentTreeView
Inherits TreeView
Public Event OnAddChild(ByVal sender As Object, ByVal e As EventArgs)
Public Event OnDelete(ByVal sender As Object, ByVal e As EventArgs)
Private _AddImageURL As String = String.Empty
Private _DeleteImageURL As String = String.Empty
Public Property AddImageURL() As String
Get
Return _AddImageURL
End Get
Set(ByVal value As String)
_AddImageURL = value
End Set
End Property
Public Property DeleteImageURL() As String
Get
Return _DeleteImageURL
End Get
Set(ByVal value As String)
_DeleteImageURL = value
End Set
End Property
Protected Overrides Function CreateNode() As TreeNode
Dim retval As ContentTreeNode = New ContentTreeNode(AddImageURL, DeleteImageURL)
AddHandler retval.OnAddChild, AddressOf ContentNode_AddChild
AddHandler retval.OnDelete, AddressOf ContentNode_Delete
Return retval
End Function
Protected Sub ContentNode_AddChild(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent OnAddChild(Nothing, Nothing)
End Sub
Protected Sub ContentNode_Delete(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent OnDelete(Nothing, Nothing)
End Sub
Public Class ContentTreeNode
Inherits TreeNode
Public Event OnAddChild(ByVal sender As Object, ByVal e As EventArgs)
Public Event OnDelete(ByVal sender As Object, ByVal e As EventArgs)
Private _AddImageURL As String = String.Empty
Private _DeleteImageURL As String = String.Empty
Private btnAddChild As ImageButton
Private btnDelete As ImageButton
Public Sub New(ByVal AddImageURL_ As String, ByVal DeleteImageURL_ As String)
_AddImageURL = AddImageURL_
_DeleteImageURL = DeleteImageURL_
End Sub
Public Property AddImageURL() As String
Get
Return _AddImageURL
End Get
Set(ByVal value As String)
_AddImageURL = value
End Set
End Property
Public Property DeleteImageURL() As String
Get
Return _DeleteImageURL
End Get
Set(ByVal value As String)
_DeleteImageURL = value
End Set
End Property
Protected Overrides Sub RenderPreText(ByVal writer As HtmlTextWriter)
End Sub
Protected Overrides Sub RenderPostText(ByVal writer As HtmlTextWriter)
CreateChildControls()
If GetTreeNodeType() <> ContentTreeNodeTypes.Root Then
btnAddChild.RenderControl(writer)
If GetTreeNodeType() <> ContentTreeNodeTypes.Category Then
btnDelete.RenderControl(writer)
End If
End If
End Sub
Private Function GetTreeNodeType() As TreeNodeTypes
Dim leaf As TreeNodeTypes = TreeNodeTypes.Leaf
If ((Me.Depth = 0) AndAlso (Me.ChildNodes.Count > 0)) Then
Return ContentTreeNodeTypes.Root
End If
If Me.Depth = 1 Then
Return ContentTreeNodeTypes.Category
End If
If ((Me.ChildNodes.Count <= 0) AndAlso Not Me.PopulateOnDemand) Then
Return leaf
End If
Return ContentTreeNodeTypes.Parent
End Function
Protected Sub CreateChildControls()
'Controls.Clear()
'***Creat Add Button***
btnAddChild = New ImageButton()
btnAddChild.ID = "btnAddChild"
btnAddChild.ImageUrl = AddImageURL
btnAddChild.ToolTip = "Add Child"
AddHandler btnAddChild.Click, AddressOf btnAddChild_Click
'***Create DeleteButton***
btnDelete = New ImageButton()
btnDelete.ID = "btnDelete"
btnDelete.ImageUrl = DeleteImageURL()
btnDelete.ToolTip = "Delete Page"
AddHandler btnDelete.Click, AddressOf btnDelete_Click
''***Add Controls***
'Me.Controls.Add(btnAddChild)
'Me.Controls.Add(btnDelete)
End Sub
Protected Sub btnAddChild_Click(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent OnAddChild(Nothing, Nothing)
End Sub
Protected Sub btnDelete_Click(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent OnDelete(Nothing, Nothing)
End Sub
Public Enum ContentTreeNodeTypes
All = 7
Leaf = 4
None = 0
Parent = 2
Root = 1
Category = 3
End Enum
End Class
End Class
1) Can I implement something like IPostBackEventHandler?
2) Is this possible since treeNode isn't a control/webcontrol?
Any help is appreciated... Thanks!!!
I think the problem is timing related, meaning the child controls are added to late in the ASP.Net page lifecycle for the event to be executed.
This might solve the issue:
Compose the whole tree structure as early as possible, e.g. in the Init event of the page.
Append the child ImageButton in the constructor of the ContentTreeNode.
Alternatively you could use a javascript context-menu so you wouldn't need to append any child-controls to the TreeNode...
After reading this post. I decided to use the following solution. First I changed my CreateChildControls method to:
Protected Sub CreateChildControls()
Dim page As Page = HttpContext.Current.CurrentHandler
Dim csm As ClientScriptManager = page.ClientScript
Dim control As WebControl = page.Master.FindControl(_ContainerID).FindControl(_ContentTreeViewID)
'***Creat Add Button***
btnAddChild = New ImageButton()
btnAddChild.ID = "btnAddChild"
btnAddChild.ImageUrl = AddImageURL
btnAddChild.ToolTip = "Add Child"
btnAddChild.Attributes.Add("onClick", csm.GetPostBackEventReference(control, String.Format("{0}:{1}", Me.Value, "Add")))
'***Create DeleteButton***
btnDelete = New ImageButton()
btnDelete.ID = "btnDelete"
btnDelete.ImageUrl = DeleteImageURL()
btnDelete.ToolTip = "Delete Page"
btnDelete.Attributes.Add("onClick", csm.GetPostBackEventReference(control, String.Format("{0}:{1}", Me.Value, "Delete")))
End Sub
Then I had to implement IPostBackEventHandler in the custom treeview to handle the postback events. Maybe not the best solution but it works well with custom event args.