Visual Basic

16-Jun-04 16:19

Thanks for friends that reply my post before....
I am binding a picture box to a path... It works fine if the path is valid. Problem comes when tha path is invalid or empty...
The code that is red highlighted is where the error come out..

Private Sub BindFields()
Try
Dim b As Binding = New Binding("Image", objDView, "CoverSample")
AddHandler b.Format, AddressOf MyPictureBox_FormatImage
[B]picBook.DataBindings.Add(b)[/B]
Catch ex As Exception
MsgBox(ex.Message, , "BindFields")
End Try
End Sub

Private Sub MyPictureBox_FormatImage(ByVal sender As Object, ByVal e As ConvertEventArgs)
Try
If Trim(e.Value.ToString) <> "" Then
Dim fi As New System.IO.FileInfo(e.Value.ToString)
If fi.Exists() Then
e.Value = Image.FromFile(e.Value.ToString)
isValidPath = True
End If
End If
Catch ex As Exception
MsgBox(ex.Message, , "MyPictureBox_FormatImage")
End Try
End Sub

Learning .NET

Dave Kreskowiak17-Jun-04 3:46

17-Jun-04 3:46

You didn't specify what the error was or where it occured. There was no highlighted text anywhere.

But, I see a problem with the way your trying to validate if a file exists or not. Check to see if the desired conversion if valid before you try and validate that the file is there, which could be done much simpler.

Private Sub MyPictureBox_FormatImage(ByVal sender As Object, ByVal e As ConvertEventArgs)
Try
    ' Check to see if this is a valid conversion.
    If Not e.DesiredType Is GetType(Image) Then
        MsgBox("FormatImage was called with the DesiredType of " & _
               e.DesiredType.ToString, , "MyPictureBox_FormatImage")
        Exit Sub
    End If
 
    ' Check if the file exists (assumes "Imports System.IO").
    ' Uses the Static version of the Exists method.
    Try
        If Not File.Exists(e.Value.ToString) Then
            MsgBox("File not found: " & e.Value.ToString, , "MyPictureBox_FormatImage")
            Exit Sub
        Else
            ' The file exists, try to create an Image object out of it.
            e.Value = Image.FromFile(e.Value.ToString)
        End If
    Catch ex As Exception
        MsgBox(ex.Message, , "MyPictureBox_FormatImage")
    End Try
End Sub

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky17-Jun-04 21:57

17-Jun-04 21:57

Private Sub BindFields()
Try
Dim b As Binding = New Binding("Image", objDView, "CoverSample")
AddHandler b.Format, AddressOf MyPictureBox_FormatImage
'This is the error since it binds to an empty path or invalid path
picBook.DataBindings.Add(b)
Catch ex As Exception
MsgBox(ex.Message, , "BindFields")
End Try
End Sub

Thanks for your reply

Learning .NET

Dave Kreskowiak18-Jun-04 10:27

18-Jun-04 10:27

OK. I've put together a quick Binding example. This code sits inside a form with a single PictureBox on it:

Imports System.IO
Imports System.Drawing
 
Public Class Form1
    Inherits System.Windows.Forms.Form
 
    ' Windows Form Designer code not included...
 
    Private myImage As myImageClass
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        myImage = New myImageClass
        myImage.Path = "D:\Pepper.JPG"
        BindFields()
    End Sub
 
    Private Sub BindFields()
        Try
            Dim b As Binding = New Binding("Image", myImage, "Path")
            AddHandler b.Format, AddressOf MyPictureBox_FormatImage
            PictureBox1.DataBindings.Add(b)
        Catch ex As Exception
            MsgBox(ex.Message, , "BindFields")
        End Try
    End Sub
 
    Private Sub MyPictureBox_FormatImage(ByVal sender As Object, ByVal e As ConvertEventArgs)
        Try
            ' Check to see if this is a valid conversion.
            If Not e.DesiredType Is GetType(Image) Then
                MsgBox("FormatImage was called with the DesiredType of " & _
                    e.DesiredType.ToString, , "MyPictureBox_FormatImage")
                Exit Sub
            End If
            ' Check if the file exists (assumes "Imports System.IO").
            ' Uses the Static version of the Exists method.
            Try
                If Not File.Exists(e.Value.ToString) Then
                    MsgBox("File not found: " & e.Value.ToString, , "MyPictureBox_FormatImage")
                    Exit Sub
                Else
                    ' The file exists, try to create an Image object out of it.
                    e.Value = Image.FromFile(e.Value.ToString)
                End If
            Catch
            End Try
        Catch ex As Exception
            MsgBox(ex.Message, , "MyPictureBox_FormatImage")
        End Try
    End Sub
End Class
 
Public Class myImageClass
    Private m_Path As String = ""
 
    Public Property Path() As String
        Get
            Return m_Path
        End Get
        Set(ByVal Value As String)
            m_Path = Value
        End Set
    End Property
End Class

If the file doesn't exist, what you think should happen does. You'll get two MessageBox's, the first, from MyPictureBox_FormatImage, saying the File does not exist, and the second, from BindFields, saying Invalid cast from System.String to System.Drawing.Image. Since the file wasn't found, the Bind failed and was appropriately caught by the BindFields exception handler.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky23-Jun-04 17:59

23-Jun-04 17:59

I have tried your code, it can catch the exception. Two message box will display, but when i using your code in my app, it doesn't work. It only display, "File not found" message box. and then it will have an error in "PictureBox1.DataBindings.Add(b)" cause it bind to an empty path. This one doesn't display message box. The error is not caught although i have using try catch function between the "PictureBox1.DataBindings.Add(b)"
Why the code doesn't work for my app, but it works ok in your form?
Please share your idea.
Thanks a bunch...

Learning .NET

Dave Kreskowiak24-Jun-04 2:52

24-Jun-04 2:52

mythinky wrote:
Why the code doesn't work for my app, but it works ok in your form?

Because you can't just copy and paste my code into yours and expect it to work. The example is just that, an example. Your have to study it to see why it works, then go back over your code and make sure that your doing the same thing. You can adapt my code to yours, but you can't just copy and paste it.

Without seeing exactly what you've done, there is no way I can tell you why mine works and yours doesn't.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky24-Jun-04 18:42

24-Jun-04 18:42

I have tried your way you doing. Of course i don't copy and paste, cause it won't suitable for my app. The problem is binding to an empty path although i have catched the exception...
Thanks...

Learning .NET

Dave Kreskowiak25-Jun-04 1:20

25-Jun-04 1:20

You might want to double check your code in BindFields(). This is where the InvalidCastException is going to be thrown by the Bindings.Add() method and caught by your Try/Catch. If this code is not correct, you'll have a problem binding to an empty string.
I'd need to see your current code to see what you missed. There is no reason that that exception wouldn't be caught.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky28-Jun-04 15:45

28-Jun-04 15:45

This is part of the frmBookDetails class.
<background color="yellow">
Imports System.Data
Imports System.Data.OleDb
Imports System.DBNull
Imports System.IO
Imports System.Drawing

Public Class frmBookDetails
Inherits System.Windows.Forms.Form

Dim objConLib As OleDbConnection = New OleDbConnection(sConnectDBLib)
Dim objDAdp As OleDbDataAdapter
Dim objDSet As DataSet
Dim objDView As DataView
Dim objCMngr As CurrencyManager

Dim objDataAdp As OleDbDataAdapter
Dim objDataSet As DataSet

Dim response As MsgBoxResult
Dim isValidPath, isNeedToClose As Boolean
Dim isValidBookTitle, isValidBookAuthor, isValidPublisher, isValidYearPublished As Boolean
Dim isValidEdition, isValidCourseBook As Boolean

Dim isBookIDChanged, isBookTitleChanged, isBookAuthorChanged, isPublisherChanged, isYearPublishedChanged As Boolean
Dim isEditionChanged, isCourseBookChanged, isCategoryChanged As Boolean

Windows Form Designer Generated Code

Private Sub FillDataSetAndView()
Try
objDView = Nothing
objDSet = New DataSet()
objConLib.Open()
objDAdp = New OleDbDataAdapter()
objDAdp.SelectCommand = New OleDbCommand("[GETBOOKDETAILS]", objConLib)
objDAdp.SelectCommand.CommandType = CommandType.StoredProcedure
objDAdp.Fill(objDSet, "BOOKDETAILS")
objDView = New DataView(objDSet.Tables("BOOKDETAILS"))
objCMngr = CType(Me.BindingContext(objDView), CurrencyManager)
objCMngr.Position = objCMngr.Count - 1

objDataAdp = New OleDbDataAdapter()
objDataAdp.SelectCommand = New OleDbCommand("SELECT * FROM BOOKCATEGORY", objConLib)
objDataAdp.SelectCommand.CommandType = CommandType.Text

objConLib.Close()
objDSet = Nothing

Catch ex As Exception
MsgBox("Error: " & ex.Source & ": " & ex.Message, MsgBoxStyle.OKOnly, "FillDataSetAndView")
End Try
End Sub

Private Sub ClearBindFields()
txtBookID.DataBindings.Clear()
txtBookTitle.DataBindings.Clear()
txtBookAuthor.DataBindings.Clear()
txtCategory.DataBindings.Clear()
txtPublisher.DataBindings.Clear()
txtYearPublished.DataBindings.Clear()
txtEdition.DataBindings.Clear()
txtCourseBook.DataBindings.Clear()
txtOriginalOwned.DataBindings.Clear()
txtCopiesOwned.DataBindings.Clear()
txtCopiesLoan.DataBindings.Clear()
txtCopiesShelves.DataBindings.Clear()
txtCopiesSold.DataBindings.Clear()
picBook.DataBindings.Clear()
End Sub

Private Sub BindFields()
Try
txtBookID.DataBindings.Add("Text", objDView, "BookID")
txtBookTitle.DataBindings.Add("Text", objDView, "Title")
txtBookAuthor.DataBindings.Add("Text", objDView, "Author")
txtCategory.DataBindings.Add("Text", objDView, "Category")
'cmbCategory.DataBindings.Add("Text", objDView, "Category")
txtPublisher.DataBindings.Add("Text", objDView, "Publisher")
txtYearPublished.DataBindings.Add("Text", objDView, "YearLastPub")
txtEdition.DataBindings.Add("Text", objDView, "Edition")
txtCourseBook.DataBindings.Add("Text", objDView, "CourseBook")
txtOriginalOwned.DataBindings.Add("Text", objDView, "NoOriginalOwned")
txtCopiesOwned.DataBindings.Add("Text", objDView, "NoCopyOwned")
txtCopiesLoan.DataBindings.Add("Text", objDView, "NoCopyonLoan")
txtCopiesShelves.DataBindings.Add("Text", objDView, "NoCopyInShelves")
txtCopiesSold.DataBindings.Add("Text", objDView, "NoCopySoldorLost")

'Dim b As Binding = New Binding("Image", objDView, "CoverSample")
'AddHandler b.Format, AddressOf MyPictureBox_FormatImage
'picBook.DataBindings.Add(b)
Catch ex As InvalidCastException
MsgBox(ex.Message, , "BindFields")
End Try
End Sub

Private Sub MyPictureBox_FormatImage(ByVal sender As Object, ByVal e As ConvertEventArgs)
Try
' Check to see if this is a valid conversion.
If Not e.DesiredType Is GetType(Image) Then
MsgBox("FormatImage was called with the DesiredType of " & _
e.DesiredType.ToString, , "MyPictureBox_FormatImage")
Exit Sub
End If
' Check if the file exists (assumes "Imports System.IO").
' Uses the Static version of the Exists method.
Try
If Not File.Exists(e.Value.ToString) Then
MsgBox("File not found: " & e.Value.ToString, , "MyPictureBox_FormatImage")
Exit Sub
Else
' The file exists, try to create an Image object out of it.
e.Value = Image.FromFile(e.Value.ToString)
End If
Catch
End Try
Catch ex As Exception
MsgBox(ex.Message, , "MyPictureBox_FormatImage")
End Try
End Sub

Learning .NET

Dave Kreskowiak28-Jun-04 17:05

28-Jun-04 17:05

mythinky wrote:
'Dim b As Binding = New Binding("Image", objDView, "CoverSample")
'AddHandler b.Format, AddressOf MyPictureBox_FormatImage
'picBook.DataBindings.Add(b)

In your code, it looks like you're trying to Bind the picturebox Image property to a column called "CoverSample" in a DataView object. I hope this CoverSample column returns the complete path to an image file?
You can check this by setting a Breakpoint on the following line (highlighted):

Private Sub MyPictureBox_FormatImage(ByVal sender As Object, ByVal e As ConvertEventArgs)
Try
' Check to see if this is a valid conversion.
If Not e.DesiredType Is GetType(Image) Then
MsgBox("FormatImage was called with the DesiredType of " & _

Then, when the app reaches this point, you can look at the values in 'e' to see what you're getting. As far as I can tell, this code will work. You'll still get the exception if you try to Bind to an empty filename, but your code is catching that and putting up a MsgBox. Correct? If you don't want to see the MessageBox's, remove them, or better yet, comment them out.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky28-Jun-04 17:21

28-Jun-04 17:21

Yeah, I am binding to a column called "CoverSample" in a DataView object.
Let's say the CoverSample contains an empty path, then the 'e' value will be "" (means empty).
There are no error occurs, but when it reach the
"picBook.DataBindings.Add(b)", error will occurs, and the error won't be caught even if i have try to catch the error. How?

The following code should have no comments, the previous code i post, the code was commented out.

Dim b As Binding = New Binding("Image", objDView, "CoverSample")
AddHandler b.Format, AddressOf MyPictureBox_FormatImage
picBook.DataBindings.Add(b)

Learning .NET

Dave Kreskowiak29-Jun-04 1:04

29-Jun-04 1:04

What's the exact error? I can't reproduce the problem. Copy and paste it into here...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky30-Jun-04 15:31

30-Jun-04 15:31

This is the error:

An unhandled exception of type 'System.InvalidCastException' occured in mscorlib.dll

Addtional information: Inavalid cast from System.String to String.Drawing.Image

This error occur on the following code:
Dim oFrmBookDetails = New frmBookDetails()
oFrmBookDetails.MdiParent = Me
oFrmBookDetails.Show() 'This is where the error occur. 'I know it from highlighted code when the error occurs.

Try
Dim b As Binding = New Binding("Image", objDView, "CoverSample")
AddHandler b.Format, AddressOf MyPictureBox_FormatImage
picBook.DataBindings.Add(b)
Catch ex As InvalidCastException
MsgBox(ex.Message, , "BindFields")
End Try

Every time i set the breakpoint, if i press F8, it will step into "Dim b As Binding...", then "AddHandler..." without going to "Adrressof MyPictureBox_FormatImage", after that "picBook.DataBindings.Add(b)", then step into "oFrmBookDetails.Show()". When showing, it execute the "MyPictureBox_FormatImage" procedure.
I think it should be execute the "MyPictureBox_FormatImage" first, then step into "oFrmBookDetails.Show()". How come it step into "oFrmBookDetails.Show()" first, then going into "MyPictureBox_FormatImage" procedure.

Learning .NET

Dave Kreskowiak1-Jul-04 1:32

1-Jul-04 1:32

Now we know where the error is actually occuring. You might want to wrap the .Show() line inside it's own Try/Catch block. I don't know if your going to get the results you expect or not. Also, is it possible that something else on the form is throwing the InvalidCastException?

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky5-Jul-04 15:26

5-Jul-04 15:26

Sorry, cause of the language barrier between us, i don't get ur mean. I already put the .Show() inside the Try/Catch but the code is in the other class (in Lib.class in my code). It's not the same class with the BookDetails.class. Do u mean i need to put the .Show() inside the BookDetails.class?

I already try to catch the InvalidCastException when try to binding the picture, u mean i need to catch the InvalidCastException of the other control? is it ur mean?
I only get one catch the InvalidCastException in my BookDetails.class.
Sorry for my language ability. Thanks

Learning .NET

Dave Kreskowiak6-Jul-04 23:49

6-Jul-04 23:49

Every time i set the breakpoint, if i press F8, it will step into "Dim b As Binding...", then "AddHandler..." without going to "Adrressof MyPictureBox_FormatImage", after that "picBook.DataBindings.Add(b)", then step into "oFrmBookDetails.Show()". When showing, it execute the "MyPictureBox_FormatImage" procedure.
I think it should be execute the "MyPictureBox_FormatImage" first, then step into "oFrmBookDetails.Show()". How come it step into "oFrmBookDetails.Show()" first, then going into "MyPictureBox_FormatImage" procedure.
I mean, put a Try/Catch block around the .Show() you have here:

... then step into "oFrmBookDetails.Show()".

The binding format will not get executed until the .Show() method of the form that is hosting the control is executed. This is when your error is occuring.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

mythinky11-Jul-04 23:04

11-Jul-04 23:04

I have put it,it work okay, two message box will displayed as your form1 application. But other problem raise, after formating the binding picture, the form doesn't load correctly. After &qt oFrmBookDetails.Show() &qt executed, it doesn't call frmBookDetails_load. But if i am not formating the binding picture, it will execute the frmBookDetails_load after it execute the &qt oFrmBookDetails.Show() &qt. Is there any other code I need to put to the formBookDetail?
Thanks. Please help me!!!

Learning .NET

Error send email?

mythinky16-Jun-04 16:03

16-Jun-04 16:03

Helo, I have a problem when sending email from VB.Net application, the error message is
"The server rejected one or more recipient addresses. The server response was: 550 5.7.1 Unable to relay for destinationemail@address.com". What is actually is the problem? How can i get out from this problem? Anyone have any idea, please reply. Thanks in advance....
------------------------
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

try
Dim objEmailMessage As System.Web.Mail.MailMessage
Dim objSMTPServer As System.Web.Mail.SmtpMail
objSMTPServer.SmtpServer = "mycomputername"

objEmailMessage = New System.Web.Mail.MailMessage
With objEmailMessage
.To = "destinationemail@address.com"
.From = txtFrom.Text
.Subject = "Great Job!"
.Body = "Want all my money?"

End With

objSMTPServer.Send(objEmailMessage)
catch exc as exception
response.write(exc.innerexception.innerexception.message)
end try
End Sub

Learning .NET

Re: Error send email?

Dave Kreskowiak17-Jun-04 3:24

17-Jun-04 3:24

The problem is that it looks like your using your local computer's SMTP server to send this. Most ISP's won't let you do this and will not relay mail for you. Instead, try using your ISP's SMTP server address in the objSMTPServer.SmtpServer line:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
    Dim objEmailMessage As System.Web.Mail.MailMessage
    Dim objSMTPServer As System.Web.Mail.SmtpMail
    objSMTPServer.SmtpServer = "smtp.myISP.com"
 
    objEmailMessage = New System.Web.Mail.MailMessage
    With objEmailMessage
        .To = "destinationemail@address.com"
        .From = txtFrom.Text
        .Subject = "Great Job!"
        .Body = "Want all my money?"
    End With
 
    objSMTPServer.Send(objEmailMessage)
    Catch exc as exception
        Response.Write(exc.InnerException.InnerException.Message)
    End Try
End Sub

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Re: Error send email?

mythinky17-Jun-04 22:02