Visual Basic

Re: Start up module for VB.NET Windows Application??

13-Nov-07 5:25

In VB6 i used to start my project from a Sub Main() which resided in a module.

This codei n sub main then initialised many things and called various forms, ie splash screen and so on.

However i cannot get the VB.NET windows application to start in this way. The property settings require that the start up be a form, unless i use a different app type (ie console app or other).

I'm new to VB.NET so would appreciate any best practice advise on this matter and how other developers are currently handling this.

Many Thanks

AliAmjad13-Nov-07 5:30

Re: Start up module for VB.NET Windows Application??

13-Nov-07 5:30

Every Class has a constructor and If you don't create one .NET will create one for you. As form is also a Class so it has its own Constructor it calls whenever we create an object of it so the best place to initialize things is the Constructor and in VB.NET its name is 'New' you can find the Constructor of your form inside 'Windows Form Generated Code'.

For Example:

Sub New

'Initialize Code here

End Sub

Hope it helps !

AliAmjad(MCP)

First make it Run THEN make it Run Fast!

barney_197213-Nov-07 5:56

Re: Start up module for VB.NET Windows Application??

13-Nov-07 5:56

I'm having difficulty finding the windows generated code. I can see the code from the forms designer but that does not contain the constructor.

AliAmjad13-Nov-07 8:06

Re: Start up module for VB.NET Windows Application??

13-Nov-07 8:06

When you click on the '+' sign besides "Windows Form Designer generated code" means when you expand it you'll see the code e.g.

Public Sub New()
    MyBase.New()

    'This call is required by the Windows Form Designer.
    InitializeComponent()

    'Add any initialization after the InitializeComponent() call
    'Your code goes here....

End Sub

I think you should buy a book because It'll really help you to clear your concepts !

hope it helps !

AliAmjad(MCP)

First make it Run THEN make it Run Fast!

barney_197213-Nov-07 21:51

Re: Start up module for VB.NET Windows Application??

13-Nov-07 21:51

AliAmjad

Thanks, i do have a book and have seen the code you mention before. But for some reason it is not in my current form.

When i select 'show all files' im the solution explorer, a plus sign appears next to my form which, if expanded, show me a Form.Designer.vb file and a Form.resx file.

I can see some code with 'Mybase.Disposing' in the Form.Designer.vb file but cannot find the form constructor anywhere.

I can create a constructor, with the same code as your comment and the IDE doesn't complain, but i would like to know why it is'nt there in the first place.

I have also tried adding in another form, just in case the code was accidentily deleted but this was the same.

Ocean4713-Nov-07 7:43

Ocean47

13-Nov-07 7:43

first create a Start up module I alway call it mMain and than create the Main() sub.

than from the project menu select properties then from the application tab select the
startup object as sub Main()

in sub Main you should put the following code at the end:

Application.EnableVisualStyles()
Application.DoEvents()
Application.Run(MainFrm)

Re: Start up module for VB.NET Windows Application??

barney_197213-Nov-07 21:46

Executing the content of a String

13-Nov-07 21:46

When i uncheck the 'Enable application framework' though what implication does this have?

JosBerb13-Nov-07 5:08

JosBerb

13-Nov-07 5:08

Hi everybody,

I'm having some problems to code something. I want to execute a function stored in a "string". I think that is easiest to understand with an example:

Public Function GetCurrentValue() As Integer<br />
      Return 67688<br />
End Function<br />
<br />
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load<br />
     Dim methodName As String = "GetCurrentValue"<br />
     Dim result As Integer<br />
     result = ExecuteFunction(methodName)<br />
    End Sub<br />

The result value should have 67688. Anybody knows how can code the "ExecuteFunction" function?

Thank you everybody

Regards,

JosBerb

AliAmjad13-Nov-07 5:37

13-Nov-07 5:37

You in need of using Delegates as they are safe type function pointers here's how to use it:

Delegate Function DelFunc() As Integer

Private Sub Form2_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load

    Dim InvDelfunc As New DelFunc(AddressOf MyFunction)
    Dim result As Integer = InvDelfunc.Invoke()
    MsgBox(result)

End Sub

Function MyFunction() As Integer
    Return 8786
End Function

Hope it helps !

AliAmjad(MCP)

First make it Run THEN make it Run Fast!

JosBerb14-Nov-07 0:11

JosBerb

14-Nov-07 0:11

Thank you for your answer but the problem with delegates is that only know the name of the function in execution time.
The reflection mode works properly.

Regards,

JosBerb

nlarson1113-Nov-07 16:37

nlarson11

13-Nov-07 16:37

research reflection

JosBerb14-Nov-07 0:19

JosBerb

14-Nov-07 0:19

nlarson11 wrote:
research reflection

Thank you a lot for your answer. Big Grin | :-D

The reflection was a perfect solution for my problem.

Regards,

JosBerb

Encryption

mpavas13-Nov-07 3:53

mpavas

13-Nov-07 3:53

Hello,

I have a requirement where I need to use Encryption/Decryption in ASP and ASP.NET application visa versa.

I have used a Blowfish .NET dll and tried to use it but on Windows 2003 SERVER backward compatibility fails.

Please help to get a VB code through which I can encrypt and decrypt a string using a Key.

Regards,
Pavas
-----------------------
[http://longjump.com/]
Dynamic business applications that manage and coordinate teams and information
-----------------------

AliAmjad13-Nov-07 5:39

13-Nov-07 5:39

You should look at System.Security.Cryptography Namespace which contains a bunch of classes use one which suits your need.

AliAmjad(MCP)

First make it Run THEN make it Run Fast!

Ocean4713-Nov-07 7:13

Ocean47

13-Nov-07 7:13

This is very simple but it works!

Public Class CL_EnCrypt
Private sPsw As String = "XAN4519CEAN4719"
Private sBox(255) As String
Private sKey(255) As String

Public Property Password() As String
Get
Return sPsw
End Get
Set(ByVal sVal As String)
sPsw = sVal
End Set
End Property

Public Function DeCrypt(ByVal sWord As String) As String
If sPsw = "" Then
MsgBox("Error you must set a password first.", MsgBoxStyle.Information, "Password not set")
Return ""
End If

Return EnDeCrypt(sWord)
End Function

Public Function EnCrypt(ByVal sWord As String) As String
If sPsw = "" Then
MsgBox("Error you must set a password first.", MsgBoxStyle.Information, "Password not set")
Return ""
End If

Return EnDeCrypt(sWord)
End Function

Private Sub RC4Initialize()
Dim sSwap As String = ""
Dim A, B As Integer

Try
For A = 0 To 255
sKey(A) = Asc(Mid$(sPsw, (A Mod sPsw.Length) + 1, 1))
sBox(A) = A
Next

B = 0
For A = 0 To 255
B = (B + sBox(A) + sKey(A)) Mod 256
sSwap = sBox(A)
sBox(A) = sBox(B)
sBox(B) = sSwap
Next
Catch ex As Exception
MessageBox.Show("Encription Error - " + ex.Message, "Encription Error", MessageBoxButtons.OK, MessageBoxIcon.Information)
End Try
End Sub

Private Function EnDeCrypt(ByVal sPlainTxt As String) As String
'This routine does all the work. Call it both to ENcrypt and to DEcrypt your data.
Dim A, I, J, K As Integer
Dim sCipherBy, sCipher, sTemp As String

Try
sCipherBy = ""
sCipher = ""
sTemp = ""
I = 0
J = 0
RC4Initialize()

For A = 1 To sPlainTxt.Length
I = (I + 1) Mod 256
J = (J + sBox(I)) Mod 256
sTemp = sBox(I)
sBox(I) = sBox(J)
sBox(J) = sTemp

K = sBox((sBox(I) + sBox(J)) Mod 256)

sCipherBy = Asc(Mid$(sPlainTxt, A, 1)) Xor K
sCipher = sCipher + Chr(sCipherBy)
Next

Return sCipher
Catch ex As Exception
MessageBox.Show("Encription Error - " + ex.Message, "Encription Error", MessageBoxButtons.OK, MessageBoxIcon.Information)
Return ""
End Try
End Function
End Class

mpavas13-Nov-07 19:20

mpavas

13-Nov-07 19:20

Thanks for the reply,

But I need to use the code in VB and .NET so it should work on both ASP and ASP.NET.

Hence I am looking for a code that is in VB and it has forward compatability.

Backward compatability gives issue in Windows 2003 server. So i want some tuhing with forward compatability

Regards,
Pavas
-----------------------
[http://longjump.com/]
Dynamic business applications that manage and coordinate teams and information
-----------------------

Steven J Jowett13-Nov-07 22:41

Steven J Jowett

13-Nov-07 22:41

Below is an encryption/decryption class I have written and use.
To Encrypt, pass the the encrypt method the text to encrypt and an encryption key. As a result a string is returned with the encrypted text.

To decrypt pass the encrypted text to the decrypt method along with the original encrytion key and as a result you should now have the original text returned by the method.

Public Class Cryptography<br />
<br />
    Public Shared Function Encrypt(ByVal Text As String, ByVal Key As String) As String<br />
        Dim sEncrypted As String = ""<br />
        Dim iKey As Integer = 0<br />
        If Key.Trim.Length = 0 Then Throw New Exception("An encryption key is required")<br />
<br />
        For iChar As Integer = 0 To Text.Trim.Length - 1<br />
            Dim iTextChar As Integer = Asc(Text.Substring(iChar, 1))<br />
            Dim iKeyChar As Integer = Asc(Key.Substring(iKey, 1))<br />
            Dim iCharacterIndex As Integer = iTextChar + iKeyChar + iChar<br />
<br />
            While iCharacterIndex > 255<br />
                iCharacterIndex = iCharacterIndex - 255<br />
            End While<br />
<br />
            sEncrypted &= Chr(iCharacterIndex)<br />
            iKey += 1<br />
            If iKey > (Key.Trim.Length - 1) Then iKey = 0<br />
        Next<br />
        Return sEncrypted<br />
<br />
    End Function<br />
<br />
    Public Shared Function Decrypt(ByVal EncryptedText As String, ByVal Key As String) As String<br />
        Dim sDecrypted As String = ""<br />
        Dim iKey As Integer = 0<br />
        If Key.Trim.Length = 0 Then Throw New Exception("An encryption key is required")<br />
<br />
        For iChar As Integer = 0 To EncryptedText.Trim.Length - 1<br />
            Dim iTextChar As Integer = Asc(EncryptedText.Substring(iChar, 1))<br />
            Dim iKeyChar As Integer = Asc(Key.Substring(iKey, 1))<br />
            Dim iCharacterIndex As Integer = iTextChar - iKeyChar - iChar<br />
<br />
            While iCharacterIndex < 1<br />
                iCharacterIndex = iCharacterIndex + 255<br />
            End While<br />
<br />
            sDecrypted &= Chr(iCharacterIndex)<br />
            iKey += 1<br />
            If iKey > (Key.Trim.Length - 1) Then iKey = 0<br />
        Next<br />
        Return sDecrypted<br />
<br />
    End Function<br />
<br />
End Class

Regards

Steve Jowett
-------------------------
Sometimes a man who deserves to be looked down upon because he is a fool, is only despised only because he is an 'I.T. Consultant'