Tutorial: How Do I Do It In VB.NET??

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Submitted on: 4/13/2002 4:22:46 PM
By: Sean Dittmar
Level: Beginner
User Rating:

By 20 Users
Compatibility:VB.NET

Users have accessed this article 19899 times.

This tutorial teaches syntax migration from VB6 to VB.NET with simple VB7/VB.NET comparison.

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Tutorial: How do I do it in VB.NET? This tutorial explain some of the more common migrating problems from VB to VB.NET.

DoEvents

VB6
DoEvents

VB7
System.Windows.Forms.Application.DoEvents

App Object

Get the full application filepath

VB6
App.Path & App.EXEName

VB7 System.Reflection.Assembly.GetExecutingAssembly.Location.ToString

Get the app's instance

VB6 App.hInstance

VB7
System.Runtime.InteropServices.Marshal.GetHINSTANCE _(System.Reflection.Assembly.GetExecutingAssembly.GetModules() _(0)).ToInt32()

Check for a previous instance

VB6
App.PrevInstance

VB7
Function PrevInstance() As Boolean
If Ubound(Diagnostics.Process.GetProcessesByName(Diagnostics.Process.GetCurrentProcess).ProcessName)) > 0 Then
Return True
Else
Return False
End If

End Sub

Graphics

Load a picture

VB6
Picture1.Picture = LoadPicture(path)

VB7
Dim img As Image = Image.FromFile(path)
Picture1.Image = img

Load a icon

VB6
Me.Icon = LoadPicture(path)

VB7
Dim ico As New Icon(path)
Me.Icon = ico
File I/0

Read from a file

VB6
Open path For Input As #1
Line Input #1, buffer
Close #1

VB7
Dim fs As FileStream = File.Open(path, FileMode.OpenOrCreate, _ FileAccess.Read)
Dim sr As New StreamReader(fs)
Buffer = sr.ReadLine
sr.Close

Write to a file

VB6
Open path For Output As #1
Write #1, buffer
Close #1

VB7
Dim fs As FileStream = File.Open(path, FileMode.OpenOrCreate, _
FileAccess.Write)
Dim sr As New StreamWriter(fs)
sr.Write(buffer)
sr.Close
Errors

Check for an error

VB6
On Error Goto errhandler
...
errhandler:
MsgBox(err.Description)

VB7
Try
     ...
     Throw New Exception("error description goes here")
     ...
Catch e as Exception
     MsgBox(e.Description)
End Try
Events

Handling an event

In VB7, there is a new keyword called AddHandler. AddHandler makes handling events a snap.

AddHandler object.event, AddressOf procedure

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Other User Comments

4/15/2002 12:17:53 AM:roswellevent
Great Tutorial 5 from me :)

4/15/2002 5:49:41 AM:Dave Lambert
Excellent stuff, but why .NET has to be so obscure is beyond me. I can see us all writing wrapper classes for the next n months to simplify the syntax back to something memorable and to what it should have been in the first place... 8-(

4/29/2002 11:13:58 AM:Sam Moses
Looks interesting. I'm still not clear on the difference in syntax though. It seems to me that this .NET code could be just as simple as the vb6 code without much real change in the mothod.

5/1/2002 9:39:04 PM:Slider
To understand why, you must look at the bigger picture - platform & OS indepentancy. This will mean that in the fututre, your application won't be tied just to 32-bit Intel platform & Windows OS. I've written a wrapper class to handle all VB7 'oddities' and am adding functions to them. Sean, great tutorial for those who need it! Keep them coming...

5/16/2002 1:51:28 PM:Pheonix
In VB6 I can do the following: picVideo.width = frmMain.width How would I do that in VB.Net?

7/8/2002 2:01:42 AM:trance
the syntax seems very similar to java, except for the ';'s

7/12/2002 2:46:48 PM:JohnB
In looking at this, it seems to me that VB.NET actually will take more time to code than VB6. Point in case: App.Path & App.EXEName VS. System.Reflection.Assembly.GetExecutingA ssembly.Location.ToString Looks to me like MS wants you to get carpel tunnel syndrome... ;) Thanks for the info though!!!

8/28/2002 12:11:47 PM:Dhaval Faria
hey.. that was gr8.. but I need some diffrent help.. can u help me? please.. I need help badly.. but its easy.. but I am not getting it.. 5 globes from me..

9/23/2002 2:22:18 AM:
great job....keep it coming along..

1/18/2003 4:20:30 PM:VBGOD
Clean...

1/31/2003 2:26:45 AM:
Good Show..

5/6/2003 5:16:39 AM:
Why it seems that VB.net is more difficult to code? I mean it takes longer code than the old VB.

5/29/2003 9:48:31 PM:
I just got my hands on .NET, I need to catch up... Excellent head start for VB6 programmers

7/4/2003 4:24:40 AM:Deepak Kumar Shaw
It's really talking... compect and to the point.. 5 from me, good work!

7/13/2003 3:15:21 PM:
im new to vb.net how about Time() and Date() functions? i want to create a clock like the one displayed in the taskbar. thanks.

11/6/2003 5:30:05 PM:
how about app.version ???

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