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

[ghafoori]

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

[ghafoori]

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)

[ghafoori]

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

[ghafoori]

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

[ghafoori]

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