نکات، ایده ها و ترفندهای کوچک برنامه نویسی در vb.net

کد:

https://barnamenevis.org/showpo...8&postcount=54

 Private Function CaptureScreen() As Image



        Dim screen As Bitmap = New Bitmap(Windows.Forms.Screen.PrimaryScreen.Bounds.W  idth, Windows.Forms.Screen.PrimaryScreen.Bounds.Height)

        Dim g As Graphics = Graphics.FromImage(screen)

        Using (g)

            g.CopyFromScreen(0, 0, 0, 0, screen.Size)

        End Using

        Return screen

    End Function

کد:
https://barnamenevis.org/showpo...9&postcount=55

'// Play a beep with default frequency

        '// and duration (800 and 200, respectively)

        Console.Beep()



        '/ Play a beep with frequency as 200 and duration as 300

        Console.Beep(200, 300)



        Media.SystemSounds.Asterisk.Play()



        Media.SystemSounds.Hand.Play()



        Media.SystemSounds.Exclamation.Play()



        Media.SystemSounds.Beep.Play()



        Media.SystemSounds.Question.Play()

https://barnamenevis.org/showpo...5&postcount=56

Imports System.Media



Dim player As Media.SoundPlayer = New SoundPlayer()

        Dim path As String = "C:\windows\media\ding.wav"

        player.SoundLocation = path ' //Set the path

        player.Play() ' //play it

https://barnamenevis.org/showpo...7&postcount=57

Imports System.Drawing.Printing



Private Sub GetInstalledPrinters()



        For Each printerName As String In PrinterSettings.InstalledPrinters

            MessageBox.Show(printerName)

        Next



    End Sub

https://barnamenevis.org/showpo...0&postcount=58

 ' // Create a TimeSpan representing 2.5 days.

        Dim timespan1 As TimeSpan = New TimeSpan(2, 12, 0, 0)



        '// Create a TimeSpan representing 4.5 days.

        Dim timespan2 As TimeSpan = New TimeSpan(4, 12, 0, 0)



        '// Create a TimeSpan representing 1 week.

        Dim oneWeek As TimeSpan = timespan1 + timespan2



        '// Create a DateTime with the current date and time.

        Dim now As DateTime = DateTime.Now



        '// Create a DateTime representing 1 week ago.

        Dim past As DateTime = now - oneWeek



        '// Create a DateTime representing 1 week in the future.

        Dim future As DateTime = now + oneWeek

مثال :‌ پیدا کردن اختلاف تعداد روزهای بین دو تاریخ :
کد:

Dim dateFrom As DateTime = DateTime.Parse("10/10/2007")

        Dim dateTo As DateTime = DateTime.Parse("11/12/2007")

        Dim ts As TimeSpan = dateTo - dateFrom

        Dim days As Integer = ts.Days

و یا :
کد:

Dim dtFirst As DateTime = New DateTime(2007, 10, 10)

        Dim dtSecond As DateTime = New DateTime(2007, 11, 12)

        Dim diffResult As TimeSpan = dtSecond.Subtract(dtFirst)

https://barnamenevis.org/showpo...3&postcount=59

Imports System.IO



Dim file As FileInfo = New FileInfo("C:\test.txt")

        file.Attributes = file.Attributes Or FileAttributes.ReadOnly Or FileAttributes.Hidden

https://barnamenevis.org/showpo...4&postcount=60

Imports System.IO





Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        MessageBox.Show(CalculateDirectorySize(New DirectoryInfo("C:\WINDOWS\System32"), True).ToString())

        

    End Sub

    

    Public Function CalculateDirectorySize(ByVal directory As DirectoryInfo, ByVal includeSubdirectories As Boolean) As Long



        Dim totalSize As Long = 0

        '// Examine all contained files.

        Dim files() As FileInfo = directory.GetFiles()

        For Each file As FileInfo In files



            totalSize += file.Length

        Next

        ' // Examine all contained directories.



        If includeSubdirectories Then



            Dim dirs() As DirectoryInfo = directory.GetDirectories()

            For Each dir As DirectoryInfo In dirs

                totalSize += CalculateDirectorySize(dir, True)

            Next

        End If

        Return totalSize

    End Function

https://barnamenevis.org/showpo...4&postcount=91

<DllImport("user32.dll")> _

Shared Function GetDC(ByVal hWnd As IntPtr) As IntPtr

    End Function

    <DllImport("user32.dll")> _

    Shared Function ReleaseDC(ByVal hWnd As IntPtr, ByVal hDC As IntPtr) As Integer

    End Function

    <DllImport("gdi32.dll")> _

    Shared Function GetPixel(ByVal hDC As IntPtr, ByVal x As Integer, ByVal y As Integer) As Integer

    End Function

    <DllImport("gdi32.dll")> _

    Shared Function SetPixel(ByVal hDC As IntPtr, ByVal x As Integer, ByVal y As Integer, ByVal color As Integer) As Integer

    End Function

    Public Shared Function GetPixel(ByVal control As Control, ByVal x As Integer, ByVal y As Integer) As Color



        Dim color As Color = color.Empty

        If Not control Is Nothing Then



            Dim hDC As IntPtr = GetDC(control.Handle)

            Dim colorRef As IntPtr = GetPixel(hDC, x, y)

            color = color.FromArgb((colorRef.ToInt32 & &HFF) Or (colorRef.ToInt32 & &HFF00 >> 8) Or (colorRef.ToInt32 & &HFF0000 >> 16))

            ReleaseDC(control.Handle, hDC)

        End If

        Return color

    End Function

    Public Shared Sub SetPixel(ByVal control As Control, ByVal x As Integer, ByVal y As Integer, ByVal color As Color)



        If Not control Is Nothing Then



            Dim hDC As IntPtr = GetDC(control.Handle)

            Dim argb As Integer = color.ToArgb()

            Dim colorRef As Integer = ((argb & &HFF0000) >> 16) Or (argb & &HFF00) Or ((argb & &HFF) << 16)

            SetPixel(hDC, x, y, colorRef)

            ReleaseDC(control.Handle, hDC)

        End If

    End Sub

منبع:https://barnamenevis.org/showpo...66&postcount=4


این کد را در کلاس مربوط به کنترل TextBox خود بنویسید :
کد:

Protected Overrides Function ProcessDialogKey(ByVal keyData As System.Windows.Forms.Keys) As Boolean



        If keyData = Keys.Return Then

            SendKeys.Send("{TAB}")

        End If

        Return MyBase.ProcessDialogKey(keyData)

    End Function

و در مورد استفاده در کنترلهای استاندارد :
کد:

Private Sub TextBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown

        If e.KeyCode = Keys.Return Then

            SendKeys.Send("{TAB}")

        End If

    End Sub

https://barnamenevis.org/showpo...6&postcount=61

Imports System.IO



 Private Sub CreateTextFile()

        Dim fs As FileStream = New FileStream("C:\test.txt", FileMode.Create)

        Dim w As StreamWriter = New StreamWriter(fs, Encoding.UTF8)

        Using (fs)

            Using (w)

                w.WriteLine(124.23)

                w.WriteLine("Salaam!")

                w.WriteLine("!")

            End Using

        End Using

    End Sub





    Private Function ReadFromTextFile() As String



        Dim sb As StringBuilder = New StringBuilder()

        Dim fs As FileStream = New FileStream("C:\test.txt", FileMode.Open)

        Dim r As StreamReader = New StreamReader(fs, Encoding.UTF8)

        Using (fs)

            Using (r)

                sb.AppendLine(r.ReadLine())

                sb.AppendLine(r.ReadLine())

                sb.AppendLine(r.ReadLine())

            End Using

        End Using

        Return sb.ToString()

    End Function

https://barnamenevis.org/showpo...7&postcount=62

Dim filename As String = "..\..\myfile.txt"

        Dim fullPath As String = "c:\Temp"

        Dim filename As String = Path.GetFileName(filename)

        Dim fullPath As String = Path.Combine(fullPath, filename)

        '// (fullPath is now "c:\Temp\myfile.txt")

https://barnamenevis.org/showpo...8&postcount=63

Dim randomFileName As String = System.IO.Path.GetRandomFileName()

و برای ایجاد نام منحصر بفرد برای فایلهای موقت :
کد:

Dim tfile As String = Path.GetTempFileName()

https://barnamenevis.org/showpo...0&postcount=64

System.Diagnostics.Process.Start("iexplore.exe", "www.barnamenevis.org")

و برای مثال در فایرفاکس :
کد:

System.Diagnostics.Process.Start("C:\Program Files\Mozilla Firefox\FireFox.exe", "www.barnamenevis.org")

https://barnamenevis.org/showpo...8&postcount=65

 Public Enum Days

        Sat = 1

        Sun

        Mon

        Tue

        Wed

        Thu

        Fri

    End Enum



    Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click



        Dim x As Integer = Days.Mon

    End Sub

https://barnamenevis.org/showpo...1&postcount=66

 Public Enum Days

        Sat = 1

        Sun

        Mon

        Tue

        Wed

        Thu

        Fri

    End Enum



    Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click



        Dim t As System.Type = GetType(Days)

        For Each s As String In Days.GetNames(t)



            ListBox1.Items.Add(s)

        Next

    End Sub

عادت کردن به میانبرها میتواند سرعت کدنویسی شما را افزایش دهد :

https://barnamenevis.org/showpo...6&postcount=67

https://barnamenevis.org/showpo...6&postcount=68

مثال :‌ تغییر رنگ پشت زمینه ی تمامی فرمهای باز در یک برنامه :

For Each frm As Form In Application.OpenForms

            frm.BackColor = Color.Fuchsia

        Next

https://barnamenevis.org/showpo...0&postcount=69

Application.Restart()

https://barnamenevis.org/showpo...8&postcount=70

برنامه تمامی message های درون message queue فعلی (از قبیل رخدادها و ...) را پردازش میکند.
کد:

Application.DoEvents()

https://barnamenevis.org/showpo...7&postcount=71

این تغییرات را در کلاس مربوط به StartUp برنامه اعمال کنید :
کد:

Imports System.Diagnostics



Class Program



    <STAThread()> _

    Shared Sub Main()



        If IsPrevInstance() Then

            Return

        End If

        Application.EnableVisualStyles()

        Application.SetCompatibleTextRenderingDefault(Fals  e)

        Application.Run(New Form1())

    End Sub



    Private Shared Function IsPrevInstance() As Boolean

        Dim processName As String = Process.GetCurrentProcess().ProcessName

        Dim instances() As Process = Process.GetProcessesByName(processName)

        If instances.Length > 1 Then

            Return True

        Else

            Return False

        End If

    End Function



End Class

https://barnamenevis.org/showpo...1&postcount=78

Imports System.Net.Mail



Class SendEmail



    Public Shared Sub SendMessage(ByVal subject As String, ByVal messageBody As String, ByVal fromAddress As String, ByVal toAddress As String, ByVal ccAddress As String)



        Dim message As MailMessage = New MailMessage()

        Dim client As SmtpClient = New SmtpClient()

        message.From = New MailAddress(fromAddress)



        '// Allow multiple "To" addresses to be separated by a semi-colon

        If toAddress.Trim().Length > 0 Then

            For Each addr As String In toAddress.Split(";")

                message.To.Add(New MailAddress(addr))

            Next

        End If



        '// Allow multiple "Cc" addresses to be separated by a semi-colon

        If ccAddress.Trim().Length > 0 Then

            For Each addr As String In ccAddress.Split(";")

                message.CC.Add(New MailAddress(addr))

            Next

        End If



        message.Subject = subject

        message.Body = messageBody

        client.Host = "YourMailServer"

        client.Send(message)

    End Sub

End Class

https://barnamenevis.org/showpo...5&postcount=79

برای این عمل به یک رویداد (MouseMove) برای pictureBox منبع نیاز دارید و دو رویداد (DragDrop) و ( DragEnter) از pictureBox مقصد. که نحوه کد کردن آن ها به شکل زیر است

Private Sub PictureBox1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove

        If e.Button = MouseButtons.Left And Not PictureBox1.Image Is Nothing Then

            PictureBox1.DoDragDrop(PictureBox1.Image, DragDropEffects.All)

        End If

    End Sub



    Private Sub PictureBox2_DragEnter(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles PictureBox2.DragEnter

        If e.Data.GetDataPresent(DataFormats.Bitmap) Then

            e.Effect = DragDropEffects.Copy

        Else

            e.Effect = DragDropEffects.None

        End If

    End Sub



    Private Sub PictureBox2_DragDrop(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles PictureBox2.DragDrop

        If e.Data.GetDataPresent(DataFormats.Bitmap) Then



            PictureBox1.Image = CType(e.Data.GetData(DataFormats.Bitmap), Image)

        End If



    End Sub

نکته : خاصیت AllowDrop مربوط به pictureBox مقصد را بایستی true کنید. دقت داشته باشید که این خاصیت، در پنجره خواص مربوط به pictureBox وجود نداره و باید اونو از طریق کد نویسی اعمال کنید.

به لینک زیر مراجعه کنید

https://barnamenevis.org/showpo...3&postcount=80

https://barnamenevis.org/showpo...1&postcount=81

توسط متد زیر می توانید هر عکسی را به حالت سیاه و سفید یا همون grayScale در بیارین

کد:

Imports System.Drawing.Imaging





Public Function GrayScaleImage(ByVal graph As Graphics, ByVal img As Image, ByVal left As Integer, ByVal top As Integer) As Image





        Dim colorMix As ColorMatrix = New ColorMatrix()

        colorMix.Matrix00 = 1 / 3.0F

        colorMix.Matrix01 = 1 / 3.0F

        colorMix.Matrix02 = 1 / 3.0F

        colorMix.Matrix10 = 1 / 3.0F

        colorMix.Matrix11 = 1 / 3.0F

        colorMix.Matrix12 = 1 / 3.0F

        colorMix.Matrix20 = 1 / 3.0F

        colorMix.Matrix21 = 1 / 3.0F

        colorMix.Matrix22 = 1 / 3.0F



        Dim imgAttrib As ImageAttributes = New ImageAttributes()

        imgAttrib.SetColorMatrix(colorMix)





        graph.DrawImage(img, New Rectangle(left, top, img.Width, img.Height), 0, 0, img.Width, img.Height, GraphicsUnit.Pixel, imgAttrib)

        Dim bmp As Bitmap = New Bitmap(img)

        Return bmp





    End Function

https://barnamenevis.org/showpo...0&postcount=82


این کلاس مختص دات نت 3.5 (به بعد) است و جهت استفاده باید System.Core رو نیز به References پروژه ی خود بیافزایید.

مثال - بدست آوردن تاریخ و زمان فعلی در توکیو :
کد:

Dim tzSource As TimeZoneInfo = TimeZoneInfo.Local

        Dim tzDestination As TimeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById("Tokyo Standard Time")

        Dim sourceTime As String = TimeZoneInfo.ConvertTime(DateTime.Now, tzSource, tzDestination).ToShortTimeString()

        MessageBox.Show(sourceTime)

https://barnamenevis.org/showpo...1&postcount=83

این روش مختص دات نت 3.5 (به بعد) است.

کد:

Imports System.Collections.ObjectModel

بدست آوردن Id و DisplayName نواحی :
کد:

 Dim zones As ReadOnlyCollection(Of TimeZoneInfo) = TimeZoneInfo.GetSystemTimeZones()

        For Each zone As TimeZoneInfo In zones

            ListBox1.Items.Add(zone.Id)

            listBox2.Items.Add(zone.DisplayName)

        Next

https://barnamenevis.org/showpo...3&postcount=84

Imports System.IO



'//To create a directory

        Directory.CreateDirectory("C:\MyNewDir")



        '//To move a directory

        Directory.Move("C:\MyNewDir", "C:\MyMovedDir")



        '//To delete a directory

        Directory.Delete("C:\MyMovedDir")



        '//To Delete a directory recursively

        Directory.Delete("C:\MyNewDir", True)



        '//To Delete a File

        File.Delete("C:\MyFile.Txt")



        '//To Move a File

        File.Move("C:\MyFile.Txt", "C:\MyOtherDir\MyFile.Txt")



        '//To Copy a file

        File.Copy("C:\MyFile.Txt", "C:\MyOtherDir\MyFile.Txt")



        '//To copy to a different file name is also possible

        File.Copy("C:\MyFile.Txt", "C:\MyOtherDir\MyNewFileName.Txt")



        '//To get information about a file, like the length

        '//You can also get the extension, directory, LastAccessedtime, 

        '//LastModifiedTime, wether the file exists or not, the creation date,

        '//attributes of the file etc, from the FileInfo class

        Dim FI As FileInfo = New FileInfo("C:\MyFile.Txt")

        Console.WriteLine("File size of MyFile.Txt: {0}", FI.Length)



        '//copy example

        Dim DateTemp As String = DateTime.Now.ToString

        File.Copy("P:\PRD\Products\AHM\prod.CD\Database\da  ta.mdb", "P:\PRD\Products\AHM\prod.CD\Database\" + DateTemp + "-data.mdb")

https://barnamenevis.org/showpo...3&postcount=86


فایلها را در مسیرC:\CopiedFolder کپی میکند :
کد:

Imports System.IO





Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        Dim fbd As FolderBrowserDialog = New FolderBrowserDialog()

        fbd.Description = "Find Folder to Copy."

        If fbd.ShowDialog() = DialogResult.OK Then



            Dim files() As String = Directory.GetFiles(fbd.SelectedPath)

            Directory.CreateDirectory("C:\CopiedFolder")

            Dim i As Integer

            For i = 0 To files.Length



                Dim tmpFileExt As String = Path.GetExtension(files(i))

                Dim tmpFileName As String = Path.GetFileNameWithoutExtension(files(i))

                File.Copy(files(i), "C:\CopiedFolder\" + tmpFileName + tmpFileExt, True)

            Next

        End If

    End Sub

https://barnamenevis.org/showpo...9&postcount=88

Imports System.IO





Sub CopyDirectory(ByVal source As DirectoryInfo, ByVal destination As DirectoryInfo)



        If Not destination.Exists Then

            destination.Create()

        End If

        '// Copy all files.

        Dim files() As FileInfo = source.GetFiles()

        For Each file As FileInfo In files

            file.CopyTo(Path.Combine(destination.FullName, file.Name))

        Next

        '// Process subdirectories.

        Dim dirs() As DirectoryInfo = source.GetDirectories()

        For Each dir As DirectoryInfo In dirs



            '    // Get destination directory.

            Dim destinationDir As String = Path.Combine(destination.FullName, dir.Name)

            '// Call CopyDirectory() recursively.

            CopyDirectory(dir, New DirectoryInfo(destinationDir))

        Next



    End Sub

https://barnamenevis.org/showpo...4&postcount=93

Imports Microsoft.Win32





 Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        ' // Create SubKey

        Registry.LocalMachine.CreateSubKey("Software\Sinpi  n", RegistryKeyPermissionCheck.ReadWriteSubTree)



        '//Create Key and Set Value

        Dim reg As RegistryKey = Registry.LocalMachine.OpenSubKey("Software\Sinpin"  , True)

        reg.SetValue("DWord", "1", RegistryValueKind.DWord)

        reg.SetValue("ExpandString", "1", RegistryValueKind.ExpandString)

        reg.SetValue("QWord", "1", RegistryValueKind.QWord)

        reg.SetValue("String", "1", RegistryValueKind.String)

        reg.SetValue("Unknown", "1", RegistryValueKind.Unknown)



        '// Delete Key

        reg.DeleteValue("DWOrd")



        '// Delete SubKey

        Registry.LocalMachine.DeleteSubKey("Software\Sinpi  n")



        '// Read Key Value

        Dim val As String = reg.GetValue("QWord").ToString()



        '// Retrieve All Keys

        For Each s As String In reg.GetValueNames()

            MessageBox.Show(s)

        Next



    End Sub

https://barnamenevis.org/showpo...3&postcount=94

Imports System.Drawing.Drawing2D





 Private Shared Function resizeImage(ByVal imgToResize As Image, ByVal size As Size) As Image



        Dim sourceWidth As Integer = imgToResize.Width

        Dim sourceHeight As Integer = imgToResize.Height



        Dim nPercent As Decimal = 0

        Dim nPercentW As Decimal = 0

        Dim nPercentH As Decimal = 0



        nPercentW = (size.Width / sourceWidth)

        nPercentH = size.Height / sourceHeight



        If nPercentH < nPercentW Then

            nPercent = nPercentH

        Else

            nPercent = nPercentW

        End If

        Dim destWidth As Integer = (sourceWidth * nPercent)

        Dim destHeight As Integer = (sourceHeight * nPercent)



        Dim b As Bitmap = New Bitmap(destWidth, destHeight)

        Dim g As Graphics = Graphics.FromImage(b)

        g.InterpolationMode = InterpolationMode.HighQualityBicubic



        g.DrawImage(imgToResize, 0, 0, destWidth, destHeight)

        g.Dispose()



        Return b

    End Function

https://barnamenevis.org/showpo...9&postcount=95

 Private Shared Function cropImage(ByVal img As Image, ByVal cropArea As Rectangle) As Image



        Dim bmpImage As Bitmap = New Bitmap(img)

        Dim bmpCrop As Bitmap = bmpImage.Clone(cropArea, bmpImage.PixelFormat)

        Return (bmpCrop)

    End Function

مثال از نحوه ی استفاده :
کد:

Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        PictureBox2.Image = cropImage(PictureBox1.Image, New Rectangle(10, 10, 100, 100))

    End Sub

https://barnamenevis.org/showpo...9&postcount=96

Imports System.Drawing.Imaging





 Public Shared Function MakeGrayscale(ByVal original As Bitmap) As Bitmap



        '    //create a blank bitmap the same size as original

        Dim newBitmap As Bitmap = New Bitmap(original.Width, original.Height)



        '//get a graphics object from the new image

        Dim g As Graphics = Graphics.FromImage(newBitmap)



        '//create the grayscale ColorMatrix

        Dim array()() As Single = New Single()() {New Single() {0.3F, 0.3F, 0.3F, 0, 0}, _

                                                  New Single() {0.59F, 0.59F, 0.59F, 0, 0}, _

                                                  New Single() {0.11F, 0.11F, 0.11F, 0, 0}, _

                                                  New Single() {0, 0, 0, 1, 0}, _

                                                  New Single() {0, 0, 0, 0, 1}}

        Dim colorMatrix As ColorMatrix = New ColorMatrix(array)



        '//create some image attributes

        Dim attributes As ImageAttributes = New ImageAttributes()



        '//set the color matrix attribute

        attributes.SetColorMatrix(colorMatrix)



        '//draw the original image on the new image

        '//using the grayscale color matrix

        g.DrawImage(original, New Rectangle(0, 0, original.Width, _

                                           original.Height), 0, 0, original.Width, _

                                           original.Height, GraphicsUnit.Pixel, attributes)



        '//dispose the Graphics object

        g.Dispose()

        Return newBitmap

    End Function



 Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        Dim b As Bitmap = PictureBox1.Image

PictureBox2.Image = MakeGrayscale(b)
End Sub

https://barnamenevis.org/showpo...4&postcount=97

Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click

        Dim day As Integer = 3



        Dim d As DaysOfWeek = NumToEnum(Of DaysOfWeek)(day)

        MsgBox(d.ToString)

    End Sub

   

    Public Function NumToEnum(Of T)(ByVal number As Integer) As T



        Return [Enum].ToObject(GetType(T), number)

    End Function



    Public Enum DaysOfWeek

        Monday

        Tuesday

        Wednesday

        Thursday

        Friday

        Saturday

        Sunday

    End Enum

https://barnamenevis.org/showpo...7&postcount=98

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim d As DaysOfWeek = StringToEnum(Of DaysOfWeek)("Monday")

        '//d is now DaysOfWeek.Monday

        MsgBox(d.ToString)



        If [Enum].IsDefined(GetType(DaysOfWeek), "Katillsday") Then

            StringToEnum(Of DaysOfWeek)("Katillsday")

        End If

    End Sub



    Public Shared Function StringToEnum(Of T)(ByVal name As String) As t



        Return [Enum].Parse(GetType(T), name)

    End Function



    Public Enum DaysOfWeek

        Monday

        Tuesday

        Wednesday

        Thursday

        Friday

        Saturday

        Sunday

    End Enum

https://barnamenevis.org/showpo...&postcount=100

Private Function rotateImage(ByVal b As Bitmap, ByVal angle As Single) As Bitmap



        '    //create a new empty bitmap to hold rotated image

        Dim returnBitmap As Bitmap = New Bitmap(b.Width, b.Height)

        '//make a graphics object from the empty bitmap

        Dim g As Graphics = Graphics.FromImage(returnBitmap)

        '//move rotation point to center of image

        g.TranslateTransform(b.Width / 2, b.Height / 2)

        '//rotate

        g.RotateTransform(angle)

        '//move image back

        g.TranslateTransform(-b.Width / 2, -b.Height / 2)

        '//draw passed in image onto graphics object

        g.DrawImage(b, New Point(0, 0))

        Return returnBitmap

    End Function



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim b As Bitmap = PictureBox1.Image

        PictureBox2.Image = rotateImage(b, 60)

    End Sub

https://barnamenevis.org/showpo...&postcount=101

با استفاده از کلمه کلیدی params مانند نمونه زیر :
کد:

Public Function Add(ByVal list() As Integer) As Integer

        Dim sum As Integer = 0

        For Each i As Integer In list

            sum += i

        Next

        Return sum

    End Function



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click



        Dim ans2 As Integer = Add(New Integer() {1, 2, 3, 4, 5, 6, 7, 8, 9, 10})



    End Sub

https://barnamenevis.org/showpo...&postcount=102

Imports System.IO

Imports System.Runtime.Serialization

Imports System.Runtime.Serialization.Formatters.Binary





 Public Sub SerializeObject(ByVal filename As String, ByVal o As Object)



        Dim stream As Stream = File.Open(filename, FileMode.Create)

        Dim bFormatter As BinaryFormatter = New BinaryFormatter()

        bFormatter.Serialize(stream, o)

        stream.Close()

    End Sub

https://barnamenevis.org/showpo...&postcount=105

برای Serialize کردن یک object در فایل XML می تونین از این کد استفاده کنین:
کد:

Imports System.Xml.Serialization



Dim xmSer As XmlSerializer = New XmlSerializer(GetType(Person))

        Dim st As FileStream = New FileStream("C:\Test.xml", FileMode.OpenOrCreate)

        Dim p As Person = New Person("Ali Rezaei", 44)

        xmSer.Serialize(st, p)

        st.Close()

https://barnamenevis.org/showpo...&postcount=106

Imports System.Xml.Serialization



Dim xmSer As XmlSerializer = New XmlSerializer(GetType(Person))

        Dim st As FileStream = New FileStream("C:\Test.xml", FileMode.Open)

        Dim p As Person = xmSer.Deserialize(st)

        st.Close()

https://barnamenevis.org/showpo...&postcount=107

برای Serialize کردن object تون توی فایل Soap می تونین از این کد استفاده کنین.
دقت کنین که باید System.Runtime.Serialization.Formatters.Soap رو Add Reference و Imports کنین.

کد:

Imports System.Runtime.Serialization.Formatters.Soap



 Dim soap As SoapFormatter = New SoapFormatter()

        Dim st As FileStream = New FileStream("C:\Test.soap", FileMode.OpenOrCreate)

        Person(p = New Person("Ali Rezaei", 33))

        soap.Serialize(st, p)

        st.Close()

https://barnamenevis.org/showpo...&postcount=108

برای بازیابی شیء تون از یک فایل SOAP می تونین از این کد استفاده کنین:
کد:

 Dim soap As SoapFormatter = New SoapFormatter()

        Dim st As FileStream = New FileStream("C:\Test.soap", FileMode.Open)

        p = soap.Deserialize(st)

        st.Close()

https://barnamenevis.org/showpo...&postcount=109

Class newClass



    Private number As Integer

    Public Sub New(ByVal _number As Integer)

        Me.number = _number

    End Sub



    Public Overloads Shared Operator +(ByVal c1 As newClass, ByVal c2 As newClass) As newClass

        Return New newClass(c1.number + c2.number)

    End Operator

End Class

تعریف یک Operator overloading همیشه باید بصورت shared و Public باشد و مقدار برگشتی آن نیز نمیتواند nothing باشد.

https://barnamenevis.org/showpo...&postcount=111

ابتدا System.Management رو به References پروژه بیفزایید و سپس :
کد:

Imports System.Management



    Public Shared Function GetCPUId() As String



        Dim cpuInfo As String = String.Empty

        '//create an instance of the Managemnet class with the

        '//Win32_Processor class

        Dim mgmt As ManagementClass = New ManagementClass("Win32_Processor")

        '//create a ManagementObjectCollection to loop through

        Dim objCol As ManagementObjectCollection = mgmt.GetInstances()

        '//start our loop for all processors found

        For Each obj As ManagementObject In objCol

            If cpuInfo = String.Empty Then



                '// only return cpuInfo from first CPU

                cpuInfo = obj.Properties("ProcessorId").Value.ToString()

            End If

        Next

        Return cpuInfo

    End Function

https://barnamenevis.org/showpo...&postcount=112

Imports System.Runtime.Serialization

Imports System.Runtime.Serialization.Formatters.Binary

Imports System.Xml.Serialization





Public Function DeSerializeObject(ByVal filename As String) As Object



        Dim o As Object

        Dim stream As Stream = File.Open(filename, FileMode.Open)

        Dim bFormatter As BinaryFormatter = New BinaryFormatter()

        o = bFormatter.Deserialize(stream)

        stream.Close()

        Return o

    End Function

https://barnamenevis.org/showpo...&postcount=113

ابتدا System.Management رو به References پروژه بیفزایید و سپس :
کد:

Imports System.Management





Public Function GetCPUManufacturer() As String



        Dim cpuMan As String = String.Empty

        '//create an instance of the Managemnet class with the

        '//Win32_Processor class

        Dim mgmt As ManagementClass = New ManagementClass("Win32_Processor")

        '//create a ManagementObjectCollection to loop through

        Dim objCol As ManagementObjectCollection = mgmt.GetInstances()

        '//start our loop for all processors found

        For Each obj As ManagementObject In objCol



            If cpuMan = String.Empty Then



                '    // only return manufacturer from first CPU

                cpuMan = obj.Properties("Manufacturer").Value.ToString()

            End If

        Next

        Return cpuMan

    End Function

https://barnamenevis.org/showpo...&postcount=114

Imports System.Management



Public Function GetHDDFreeSpace(ByVal drive As String) As Double



        '    //check to see if the user provided a drive letter

        '   //if not default it to "C"

        If drive = "" Or drive Is Nothing Then



            drive = "C"

        End If

        '//create our ManagementObject, passing it the drive letter to the

        '//DevideID using WQL

        Dim disk As ManagementObject = New ManagementObject("Win32_LogicalDisk.DeviceID=""" + drive + ":\""")

        '//bind our management object

        disk.Get()

        '//return the free space amount

        Return Convert.ToDouble(disk("FreeSpace"))

    End Function

https://barnamenevis.org/showpo...&postcount=115

ابتدا System.Management رو به References پروژه بیفزایید و سپس :
کد:

Imports System.Management



 Public Function getHDDSize(ByVal drive As String) As Double



        '    //check to see if the user provided a drive letter

        '   //if not default it to "C"

        If drive = "" Or drive Is Nothing Then



            drive = "C"

        End If

        '//create our ManagementObject, passing it the drive letter to the

        '//DevideID using WQL

        Dim disk As ManagementObject = New ManagementObject("Win32_LogicalDisk.DeviceID=""" + drive + ":\""")

        '//bind our management object

        disk.Get()

        '//return the HDD's initial size

        Return Convert.ToDouble(disk("Size"))

    End Function

https://barnamenevis.org/showpo...&postcount=116

آبجکتهای string در دات نت immutable (غیرقابل تغییر) هستند :‌به این معنا که پس از مقدار گرفتن، دیگر قابل تغییر نیستند.

به مثال زیر دقت کنید :
کد:

 Dim temp As String = "a"

        temp = temp + "b"

        temp += "c"

        temp += "d

"

در این مثال ابتدا یک آبجکت از نوع string میسازید، اما در خطوط بعدی با هر بار تغییر مقدار آن؛ آبجکتهای قدیمی فراموش و یک آبجکت جدید از نوع string - با مقدار جدید - ساخته میشود.
به این ترتیب میشه انتظار داشت که کد زیر چه سربار وحشتناکی روی منابع سیستم میتونه داشته باشه :
کد:

Dim s2 As String = New String("x", Int32.Parse(args(0)))

        Dim loops As Integer = Int32.Parse(args(1))

        Dim j, i As Integer

        For j = 0 To 10000000

            Dim s As String = ""

            For i = loops To 0 Step -1

                s += s2

            Next

        Next

بصورت کلی در حالتیکه اعمال تغییرات زیاد روی رشته ها نیاز باشد بهتر است آبجکتی از کلاس StringBuilder ساخته و با خاصیت Append آن کار کنیم.

مثال - پیاده سازی همان کد قبلی :
کد:

Dim s2 As String = New String("x", Int32.Parse(args(0)))

        Dim loops As Integer = Int32.Parse(args(1))

        Dim i, j As Integer

        For j = 0 To 10000000

            Dim sb As StringBuilder = New StringBuilder()

            For i = loops To 0 Step -1

                sb.Append(s2)

            Next

            sb.ToString()

        Next

https://barnamenevis.org/showpo...&postcount=117

با فرض داشتن کلاسی مانند :
کد:

Public Class Person

    Public Sub New(ByVal _firstName As String, ByVal _lastName As String)



        Me.FirstName = _firstName

        Me.lastName = _lastName

    End Sub

    Private _firstName As String

    Public Property FirstName() As String

        Get

            Return _firstName

        End Get



        Set(ByVal value As String)

            _firstName = value

        End Set

    End Property

    Private _lastName As String

    Public Property LastName() As String

        Get

            Return _lastName

        End Get

        Set(ByVal value As String)

            _lastName = value

        End Set

    End Property

End Class

میتونیم بنویسیم :
کد:

Dim persons As List(Of Person) = New List(Of Person)

        persons.Add(New Person("ali", "ahmadi"))

        persons.Add(New Person("maryam", "hosseini"))