.NET (Core and Framework)

Quote:

My application creates a chart in Excel, then exports the chart as a .png file.

It works fine the first time i generate a chart, But when i do it a second time i get this error.

An unhandled exception of type System.Runtime.InteropServices.ExternalException; occurred in System.Drawing.dll
Additional information: A generic error occurred in GDI+

Code where i get an error.

Dim workbook As New Workbook()
       workbook.LoadFromFile("Test.xls")
       Dim sheet As Worksheet = workbook.Worksheets(0)
       Dim imgs As Image() = workbook.SaveChartAsImage(sheet)
        imgs(0).Save(String.Format("img-0.png", ImageFormat.Png)) 'Gets first chart from excel (Error on this line)

 
       Me.PictureBox2.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage
       Me.PictureBox2.TabIndex = 1
       Me.PictureBox2.TabStop = False
      
 
       PictureBox2.Image = Image.FromFile("img-0.png")

Quote:

Dim diffR As Integer = CInt(pixelR - searchedR) '<=================
' pixelR is 128, searchedR is 0

<blockquote class="quote"><div class="op">Quote:</div>Function true_Black_and_White_Unsafe_Methode( _
        MyImage As Image,
        searchedR As Byte, searchedG As Byte, searchedB As Byte, _
        Tolerance As Integer) As Image

        ' Source:
        ' http://www.codeproject.com/Articles/617613/Fast-pixel-operations-in-NET-with-and-without-unsa

        Dim Bmp8 As New Bitmap(MyImage.Width, MyImage.Height, PixelFormat.Format1bppIndexed)
        Dim imageData As BitmapData = Bmp8.LockBits(New Rectangle(0, 0, MyImage.Width, _
            MyImage.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb)

        Dim bytesPerPixel As Integer = 3
        Dim scan0 As Integer = imageData.Scan0
        Dim stride As Integer = imageData.Stride

        Dim unmatchingValue As Byte = 0
        Dim matchingValue As Byte = 255
        Dim toleranceSquared As Integer = Tolerance * Tolerance
        Dim y As Integer
        For y = 0 To imageData.Height - 1

            Dim row(scan0 + (y * stride)) As Integer
            Dim x As Integer
            For x = 0 To imageData.Width - 1

                ' Watch out for actual order (BGR)!
                Dim bIndex As IntPtr = x * bytesPerPixel
                Dim gIndex As IntPtr = bIndex + 1
                Dim rIndex As IntPtr = bIndex + 2

                Dim pixelR As Byte = row(rIndex)
                Dim pixelG As Byte = row(gIndex)
                Dim pixelB As Byte = row(bIndex)

                ' here is the system overflow exception
                Dim diffR As Integer = CInt(pixelR - searchedR) '<================= 
' pixelR is 128, searchedR is 0</blockquote>

                
Dim diffR As Integer = CInt(pixelR - searchedR) '<================= 
' pixelR is 128, searchedR is 0

                Dim diffG As Integer = CInt(pixelG - searchedG)
                Dim diffB As Integer = CInt(pixelB - searchedB)

                Dim distance As Integer = diffR * diffR + diffG * diffG + diffB * diffB

                If distance > toleranceSquared Then
                    row(rIndex) = row(bIndex) = row(gIndex) = unmatchingValue
                Else
                    row(rIndex) = row(bIndex) = row(gIndex) = matchingValue
                End If
            Next
        Next

        Bmp8.UnlockBits(imageData)
        Return Bmp8
    End Function</blockquote>

Imports System.IO
Imports System.Net.Mail
Imports System.Net

Sub Main()
Try
Dim loMessage As MailMessage = Nothing
Dim loClient As SmtpClient = Nothing

loClient = New SmtpClient()
loClient.Timeout = 50000
loClient.Host = "smtp.gmail.com"
loClient.Port = 587
loClient.EnableSsl = True
loClient.Credentials = New System.Net.NetworkCredential("test@gmail.com", "xxxxxxxxxx")

loMessage = New MailMessage()
loMessage.IsBodyHtml = True
loMessage.From = New MailAddress("xxxxxx@gmail.com")
loMessage.To.Add(New MailAddress("xxxxxx@bluewin.ch"))
loMessage.Subject = "Betreff"
loMessage.Body = "Test Ihre Daten..."

loClient.Send(loMessage)

Catch ex As Exception
'MsgBox(ex.ToString)
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter("c:\tmp\err.txt", True)
file.WriteLine(ex.ToString)
file.Close()

End Try
End Sub