(Visualbasic) The One stop simple help thread

Discussion in 'Mixed Languages' started by stevemk14ebr, Jan 7, 2012.

  1. stevemk14ebr

    stevemk14ebr MDL Senior Member

    Jun 23, 2010
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    #1 stevemk14ebr, Jan 7, 2012
    Last edited by a moderator: Apr 20, 2017
    The goal of this is to provide simple answers of some of the harder visualbasic concepts to grasp (such as drawing to a form or creating grids with a snap-to function)

    1)How to draw the the form
    Code:
     Protected Overrides Sub OnPaint( _
       ByVal e As System.Windows.Forms.PaintEventArgs)
            'drawing score
            Dim g As Graphics = e.Graphics
            g.DrawString("Score:" & score, _
            New Font("Arial", 16), _
            Brushes.Black, 1, 1)
    end sub
    In This the value of score is drawn to the form at point 1,1; if this score was to continue to increase you would have to invalidate the area where that string is drawn(place a rectangle with visibility set to false over that area and use this code:)
    Code:
    Dim bmpcontainter As RectangleF
                bmpcontainter = inval.Bounds
                Me.Invalidate(Rectangle.Round(bmpcontainter))
    this code creates a series of points containing the bounds of the rectangle(inval) then uses those points to invalidate only that area

    2) how to draw a grid with a snap-to function
    a) drawing the grid
    Code:
    dim g as graphics
    g=me.creategraphics
     For x = 0 To 19
                For y = 0 To 24
                    r = New Rectangle(x * 32, y * 32, 32, 32)
                    g.DrawRectangle(Pens.Black, r)
                Next
            Next
    b) the snap-to funtion
    This code is to made to have any point you pass to it find the nearest point on the grid you made
    Code:
    'declares
     Dim m_GridX As Integer = 32
        Dim m_gridy As Integer = 32
        Dim xgrd, ygrd As Integer
    Code:
     Private Sub SnapToGrid(ByRef X As Integer, ByRef Y As Integer)
            Dim ix As Integer = CInt(X / m_GridX)
            Dim iy As Integer = CInt(Y / m_gridy)
            xgrd = ix * m_GridX
            ygrd = iy * m_gridy
        End Sub
    To use this:
    Code:
    Dim p As Point
            p = Me.PointToClient(MousePosition)
            SnapToGrid(p.X, p.Y)
    this gets the mouse position,finds nearest point on grid stored in xgrd and ygrd

    3) drawing lines to the form and keeping them after form refresh, thanks to Calistoga for this
    add this code
    Code:
    Class Line
        Private m_start As Point, m_end As Point
    
        Public Sub New(start As Point, [end] As Point)
            Me.m_start = start
            Me.m_end = [end]
        End Sub
    
        Public Property Start() As Point
            Get
                Return Me.m_start
            End Get
            Set(value As Point)
                Me.m_start = value
            End Set
        End Property
    
        Public Property [End]() As Point
            Get
                Return Me.m_end
            End Get
            Set(value As Point)
                Me.m_end = value
            End Set
        End Property
    End Class
    Use this code to make a list of lines to be repainted on form refresh
    Code:
    Imports System.Collections.Generic ' Place this in the top of your code file
    Dim list As List(Of Line) = New List(Of Line)
    then this code to make a line and add it to list to repaint on form refresh
    Code:
    'change smooothign to hq, drawing line on form with pen point 1 and point 2
                Dim pen As New Pen(Brushes.Black, 3)
                g.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
                g.DrawLine(pen, mp1, mp2)
                Dim line As Line = New Line(mp1, mp2)
                list.Add(line)
    then use this to redraw all the lines in that list when form is repainted
    Code:
    Private Sub Form1_Paint(sender As System.Object, e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
            
                For Each L As Line In list
                    Dim pen As New Pen(Brushes.Black, 3)
                    pen.StartCap = Drawing2D.LineCap.RoundAnchor
                    pen.EndCap = Drawing2D.LineCap.ArrowAnchor
                    g.SmoothingMode = Drawing2D.SmoothingMode.HighQuality
                    g.DrawLine(pen, L.Start, L.End)
                Next
          
        End Sub
    4) Using the arrow keys
    Add this function
    Code:
     Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Integer) As Integer
    then in a timer set to every 1ms or so
    Code:
    'pacface is an imagebox
    If GetAsyncKeyState(Keys.Right) then
    pacface.Left += 1
    end if
    
    If GetAsyncKeyState(Keys.Left) then
    pacface.left-=1
    end if
    
    If GetAsyncKeyState(Keys.Up) then
    pacface.Top -= 1
    end if
    
    If GetAsyncKeyState(Keys.Down) then
    pacface.Top += 1
    end if
    5) Creating controls in runtime
    Code:
    'can change picture box to textbox,richtextbox,any control really(few if any exceptions)
    Dim newsize As New Size(150, 100)
    Dim pb5 As New PictureBox
                With pb5
                    .SizeMode = PictureBoxSizeMode.StretchImage
                    .Name = "Picturebox1"
    'resized image is a bitmap i declared earlier (not in this tutorial,out of one of my projects)
                    .Image = resizedimage5
    'I incorparated the snap-to grid in this using xgrd and ygrd
                    .Location = New Point(xgrd, ygrd)
                    .Size = newsize
                    .BackColor = Color.Transparent
                End With
    'MUST HAVE ME.CONTROLS.ADD OR IT WONT WORK
    Me.Controls.Add(pb5)
    you can add this before me.controls.add() if you want to use the controls events (such as onclick or ontextchanged), you can change the handle added
    Code:
     AddHandler pb5.TextChanged, AddressOf Me.pb5_TextChanged
    Then to use that handle you need a sub that references the name (same name as the words after Addressof, incase you don't know this)
    This example obviously won't work because in our example our control is a picture box, if you change it to a textbox then this example would be correct
    Code:
     Private Sub pb5_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
    
            ' stuff here
    
        End Sub
    6) Removing the controls you just added in runtime THANKS AGAIN TO CALISTOGA
    'loops through all control on form and if it is a picturebox or richtext box add it to a list then loop through that list and remove the contols in the list
    Code:
    'declares
     Dim listc As List(Of Control) = New List(Of Control)
    Code:
     Dim c As Control
            For Each c In Me.Controls
                If (TypeOf c Is PictureBox Or TypeOf c Is RichTextBox) Then
                    listc.Add(c)
                End If
            Next
            For Each c In listc
                Me.Controls.Remove(c)
            Next
            listc.Clear()
    me.refresh
    
    7) Check the md5 of application (tests on itself)-from http://forums.mydigitallife.net/threads/32649-VB-NET-or-C-How-to-%28HELP%29 CR32 check is in a thread reply below by The Dev
    Code:
    Imports System.Security.Cryptography
    
    Public Function MD5Sec(ByVal filepath As String) As String
    
            Using reader As New System.IO.FileStream(filepath, IO.FileMode.Open, IO.FileAccess.Read)
                Using md5 As New System.Security.Cryptography.MD5CryptoServiceProvider
    
                    Dim hash() As Byte = md5.ComputeHash(reader)
    
                    Return ByteArrayToString(hash)
    
                End Using
            End Using
    
        End Function
    
        Private Function ByteArrayToString(ByVal arrInput() As Byte) As String
    
            Dim sb As New System.Text.StringBuilder(arrInput.Length * 2)
    
            For i As Integer = 0 To arrInput.Length - 1
                sb.Append(arrInput(i).ToString("X2"))
            Next
    
            Return sb.ToString().ToUpper
    
        End Function
    
    'usage below, mine is in the form load event and 'Self_MD5' can be a textbox, label, linklabel etc
            Try
                Self_MD5.Text = MD5Sec(Environment.CurrentDirectory + "\applicationnamehere.exe")
            Catch md5null As Exception
                Self_MD5.Text = ""
            End Try
    8) changing reg keys and checking if they exist-BE VERY SURE U MODIFY THE REG KEY LOCATION BECAUSE MY EXAMPLES WILL CHANGE THE VALUES FOR HDD MODE (are and excerpt from my AHCI changer app)

    to check if a key exists
    Code:
     Imports System.IO
    -need to import io for all file operations including reg keys
    Code:
     
    'if get value returns nothing then exists3 (e3) = false else returns true
    If My.Computer.Registry.GetValue _
                ("HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msahci", "Start", Nothing) Is Nothing Then
                    e3 = False
                Else
                    e3 = True
    End If
    how to change a key

    Code:
     
    If e3 = True Then
                                Dim autoshell = My.Computer.Registry.LocalMachine.OpenSubKey("System\CurrentControlSet\Services\msahci", True)
                                '' Set the value to 0
                                autoshell.SetValue("Start", 0)
                                autoshell.Close()
    End If
    how to check the value of a key
    i use byte because it's either 1 or 0 so no point in integer and using more memory
    Code:
    Dim v3 as byte
    Code:
     
    If e3 = True Then
                                   v3 = My.Computer.Registry.GetValue _
                                   ("HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\msahci", "Start", Nothing)
    End If
    Code:
    if v3=0 then 'do whatever
    9) close all open windows -Josh Cell, http://forums.mydigitallife.net/threads/33487-VB-NET-All-Active-window-will-be-and-close-it
    Code:
    For Each MainProc As Process In Process.GetProcesses(Environment.MachineName)
        If (MainProc.MainWindowHandle <> IntPtr.Zero) Then
            MainProc.Kill()
        End If
    Next
    
    10) create a restore point without a dialog (silently) -link to thread adapted from this vb6 code
    Code:
     
            'will create a restore point silently, may freeze app for ~5 seconds, this can be fixed with a background worker or a new thread
            Dim obj As Object
            obj = GetObject("winmgmts:{impersonationLevel=impersonate}!root/default:SystemRestore")
    
            'The date and ID are auto added
            Call obj.CreateRestorePoint("Give it a name", 12, 100)
    11) check how many restore points are on a computer (if you just made on using step 10, you must restart the app for it to count your new restore)
    Code:
     Public Sub ListPoints() 'Adds all Restore Points to a ListView
    
            Dim o As Object
            Dim sr As Object
            Dim num As Byte
    
            'Get all points and add them to "o"
            o = GetObject("winmgmts:root/default").InstancesOf("SystemRestore")
    
            'Scroll through "o"
            For Each sr In o
                num += 1
                'Adds a point to a ListView then shows num of restore not that after 
                'creating the restore it will not show a nother restore until restarting app
                ListView2.Items.Add(sr)
                MessageBox.Show(num)
    Next sr
    
        End Sub
    12) Remap function- this will convert a large range into a smaller range, say you have x in the range 500-0(the range is the numbers that say could be x on input from a joystick), you can remap x to a smaller range to say 50-0. If you need an example of how to implement this my signature has a joystick program that uses the map function feel free to download it and look at the source
    Code:
     Public Function map(x As Integer, inmin As Integer, inmax As Integer, outmin As Integer, outmax As Integer)
            'x is the value in a range, the first range is the range that x is in, second is range x is being converted to
            Dim int As Integer
            int = (x - inmin) * (outmax - outmin) / (inmax - inmin) + outmin
            Return Math.Round(int)
        End Function
    STATUS OF UPDATES:
    added #12
     
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  2. QuantumBug

    QuantumBug MDL Developer

    Mar 7, 2012
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    Awesome, glad to see my post was good enough to go in your list!
     
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  3. stevemk14ebr

    stevemk14ebr MDL Senior Member

    Jun 23, 2010
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    yes very useful thanks alot
     
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  4. QuantumBug

    QuantumBug MDL Developer

    Mar 7, 2012
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    #4 QuantumBug, Jul 27, 2012
    Last edited by a moderator: Apr 20, 2017
    Application CRC32 hashing(checks on self)

    Imports:
    Code:
    #Region "Imports"
    Imports System.Security
    Imports System.Security.Cryptography
    #End Region
    
    Code:
    #Region "CRC32 Hashing"
        Private filePath As String
        Private fileStream As FileStream
        Private streamWriter As StreamWriter
        Public Delegate Function ReturnTextDelegate() As String
        Public Function GetCrc32(ByRef stream As IO.Stream) As Integer
            Dim crc32Table() As Integer
            Const BufferSize As Integer = 1024
            Dim dwPolynomial As Integer = &HEDB88320
            Dim i As Integer, j As Integer
            ReDim crc32Table(256)
            Dim dwCrc As Integer
            For i = 0 To 255
                dwCrc = i
                For j = 8 To 1 Step -1
                    If (dwCrc And 1) Then
                        dwCrc = ((dwCrc And &HFFFFFFFE) \ 2&) And &H7FFFFFFF
                        dwCrc = dwCrc Xor dwPolynomial
                    Else
                        dwCrc = ((dwCrc And &HFFFFFFFE) \ 2&) And &H7FFFFFFF
                    End If
                Next j
                crc32Table(i) = dwCrc
            Next i
            Dim crc32Result As Integer
            crc32Result = &HFFFFFFFF
            Dim buffer(BufferSize) As Byte
            Dim readSize As Integer = BufferSize
            Dim count As Integer = stream.Read(buffer, 0, readSize)
            Dim c As Integer
            Dim iLookup As Integer
            Dim tot As Integer = 0
            Do While (count > 0)
                For c = 0 To count - 1
                    iLookup = (crc32Result And &HFF) Xor buffer(c)
                    crc32Result = ((crc32Result And &HFFFFFF00) \ &H100) And &HFFFFFF
                    crc32Result = crc32Result Xor crc32Table(iLookup)
                Next c
                count = stream.Read(buffer, 0, readSize)
            Loop
            GetCrc32 = Not (crc32Result)
        End Function
    #End Region
    
    Usage:
    Code:
                Try
                    Dim mainapp As String = CStr(AppDomain.CurrentDomain.FriendlyName)
                    Dim crc As Integer = 0
                    Dim path As String = DirectCast(Invoke(New ReturnTextDelegate(AddressOf mainapp.ToString), New Object(-1) {}), String)
                    Dim stream As FileStream = File.OpenRead(path)
                    crc = GetCrc32(stream)
                    app_checksum.Text = String.Format("{0:X8}", crc)
                    stream.Close()
                Catch ex As Exception
                    MsgBox(ex.message)
                End Try
    
    :D
     
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  5. QuantumBug

    QuantumBug MDL Developer

    Mar 7, 2012
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    :D

    Dude, how good a developer with VB are you, inbox me? May need some team collab.
     
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  6. stevemk14ebr

    stevemk14ebr MDL Senior Member

    Jun 23, 2010
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    i've reformated some of the code to make it easier to read
     
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  7. mustercard

    mustercard MDL Novice

    Jan 23, 2013
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    I want to learn visual basic, but I don't have its program.
    There are many version in many thread, and there isn't stick thread or official thread.
    So where I can get that program link? And maybe with its key too o_O

    Sorry for my poor english, thanks a lot :worthy:
     
  8. splinter_

    splinter_ MDL Novice

    Dec 17, 2012
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    Try on website called vbtutor.net and homeandlearn.co.uk
     
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  9. stevemk14ebr

    stevemk14ebr MDL Senior Member

    Jun 23, 2010
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    When you say "its program" I assume you mean the IDE or the program used to write visualbasic code inside. For that i highly recommend the Microsoft Visual Studio express 2012- link http://www.microsoft.com/visualstudio/eng/products/visual-studio-express-products

    P.S your english is fine if i can read it and understand the point then you're good, and if you need any further help fell free to make your own thread right here in mixed languages and i'll answer your questions
     
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  10. QuantumBug

    QuantumBug MDL Developer

    Mar 7, 2012
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    #10 - App may stop working for 5+ seconds, this can be solved with a Thread or Background Worker :)
     
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  11. Pr3acher

    Pr3acher MDL Member

    Aug 24, 2012
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    Hi, well if you wanna learn a programming language (C/C++/C#/Vb or any other language), you must have an IDE to dev' with, check Code::Blocks for free and open source, or VS 2012 the M$ one. Also this can be useful for some tips: http://www.codeproject.com/
     
  12. stevemk14ebr

    stevemk14ebr MDL Senior Member

    Jun 23, 2010
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    oops forgot to say that, lol, if you follow that link i actually suggest that in the thread lol
     
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