Visual Basic

1-Jul-08 2:47

Scenerio: predecessor built a screencapture VB applet to call from a shortcut in third-party app...but I need to modify it to maximize the app before snapshot.
Hints? how do I maximaize an already open app?

Another option wwould be to capture just the active window instead of full screen...

Public Class Form1
    Dim memoryImage As Bitmap 'The bitmap of the screen
    Dim srcWidth As Int16 'The width of the usable screen
    Dim srcHeight As Int16 'The height of the usable screen
    Dim tmr As New System.Windows.Forms.Timer


    Private Sub PrintDocument1_PrintPage(ByVal sender As System.Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage
        Dim dstWidth As Int16 'Destination width
        Dim dstRect As Rectangle 'Destination height
        Dim srcRect As New Rectangle(0, 0, srcWidth, srcHeight) 'Source Rectangle

        'Set the dstWidth to the printable height of the document. The height is used
        'because the document is printed in landscape
        dstWidth = PrintDocument1.DefaultPageSettings.PrintableArea.Height
        dstRect.Width = dstWidth ' Set the width of the destination rectangle

        'Scale the height in relation to the width and the source rectangle
        dstRect.Height = (dstWidth / srcWidth * srcHeight)

        'Draw the image scaling from the srcRect to the dstRect
        e.Graphics.DrawImage(memoryImage, dstRect, srcRect, GraphicsUnit.Pixel)
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        PrintDocument1.DocumentName = "Screen Print" 'Name the document
        PrintDocument1.DefaultPageSettings.Landscape = True 'Swith to landscape
        PrintPreviewDialog1.ShowDialog() 'Show the print preview dialog
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        Me.Visible = False 'Hide the form

        tmr.Enabled = True
        tmr.Interval = 1500
        AddHandler tmr.Tick, AddressOf Me.TimerTick
        tmr.Start()





    End Sub

    Private Sub TimerTick(ByVal Sender As Object, ByVal e As EventArgs)
        Dim myGraphics As Graphics
        Dim s As Size
        tmr.Enabled = False
        tmr.Stop()

        'Set the srcWidth and srcHeight to the working dimensions of the screen
        srcWidth = System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Width
        srcHeight = System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Height
        s.Width = srcWidth 'Set the width of the size object
        s.Height = srcHeight 'Set the height of the size object


        myGraphics = Me.CreateGraphics
        'Create a bitmap based on the size of the screen
        memoryImage = New Bitmap(srcWidth, srcHeight, myGraphics)

        'Create a graphics object to paint the bitmap
        Dim memoryGraphics As Graphics = Graphics.FromImage(memoryImage)

        'Get a capture of the screen
        memoryGraphics.CopyFromScreen(200, 0, 0, 0, s)

        'PictureBox1.Image() = memoryImage
        Button1_Click(Sender, e)
        Application.Exit()
    End Sub
End Class

modified on Tuesday, July 1, 2008 9:33 AM

jzonthemtn1-Jul-08 4:54

1-Jul-08 4:54

If I understand your question correctly, get the HWND of the window you want to take a screen capture of and then call the ShowWindow()[^] API passing SW_SHOWMAXIMIZED.

JLTBDY1-Jul-08 5:19

1-Jul-08 5:19

That sounds like what I've seen on Technet/Help....problem is I'm not a programmer & dont know the syntax or where in my vb app it should go(ie form1_load)....how would you script that, given the app name of "CDA"?
This is great OJT....I'll keep digging in Help documents, but your help is great to get me putting the pieces together. Thanks! Smile | :)

jzonthemtn1-Jul-08 5:34

1-Jul-08 5:34

Disclaimer: This code may not be 100% syntax-correct but it should get you started (particularly the call to FindWindowEx, my memory is unsure.)

In declarations:

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function FindWindowEx(ByVal parentHandle As IntPtr, _
                      ByVal childAfter As IntPtr, _
                      ByVal lclassName As String, _
                      ByVal windowTitle As String) As IntPtr

Private Declare Auto Function GetDesktopWindow Lib "user32.dll" () As IntPtr
End Function

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Boolean
End Function

In code, before where the screen shot is taken:

' Get the window's handle
Dim WindowTitle as String = "Notepad"
Dim WindowToMax as IntPtr = FindWindowEx(GetDesktopWindow(), IntPtr.Zero, IntPtr.Zero, "WindowTitle")

' Maximize it
ShowWindow(WindowToMax, 3) ' 3 is for ShowMaximized

I use FindWindowEx to find the window to maximize (the window with "Notepad" as the title). Then pass the window's handle to ShowWindow(). There's a lot of examples out there for FindWindowEx and ShowWindow in case you need more.

JLTBDY7-Jul-08 7:28

7-Jul-08 7:28

Arrgh...so close...
I got a .Net security error

The type of the first permission that failed was:
System.Security.Permissions.SecurityPermission
The Zone of the assembly that failed was:
MyComputer

Heres my modifications:

<Runtime.InteropServices.DllImport("user32.dll")> _
Private Shared Function FindWindowEx(ByVal parentHandle As IntPtr, _
ByVal childAfter As IntPtr, _
ByVal lclassName As String, _
ByVal windowTitle As String)

End Function
Declare Auto Function GetDesktopWindow Lib "user32.dll" () As IntPtr

<Runtime.InteropServices.DllImport("user32.dll")> _
Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Boolean
End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim WindowTitle As String = "QuadraMed CPR - Saint Francis Hospital Ulticare System"
        Dim WindowToMax As IntPtr = FindWindowEx(GetDesktopWindow(), IntPtr.Zero, IntPtr.Zero, "WindowTitle")
        ShowWindow(WindowToMax, 3) ' 3 is for ShowMaximized

    End Sub

jzonthemtn7-Jul-08 8:11

7-Jul-08 8:11

Try this one:

Imports System.Runtime.InteropServices

Public Class Form1

    <Runtime.InteropServices.DllImport("user32.dll")> _
        Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Boolean
    End Function

    <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
    Private Shared Function FindWindow( _
         ByVal lpClassName As String, _
         ByVal lpWindowName As String) As IntPtr
    End Function

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

        Dim NotepadHwnd As System.IntPtr = FindWindow(Nothing, "Untitled - Notepad")
        MsgBox(NotepadHwnd.ToString)

        ShowWindow(NotepadHwnd, 3)

    End Sub

End Class

FindWindowEx is probably overkill, and I should have mentioned FindWindow instead. The window title "Untitled - Notepad" has to match exactly. If you don't know what the window title will be, you can enumerate all desktop windows and then call GetWindowText for each one until you find the window that you want to maximize.

JLTBDY8-Jul-08 12:00

8-Jul-08 12:00

Almost there. My security error was due to not having published(could not run from VS CTRL-F5)

It works great on Notepad, but not on the 3rd party app....how do I "enumerate all desktop windows and then call GetWindowText for each one "?

Smile | :)

Appreciate your patience & walking me thru this!

jzonthemtn8-Jul-08 12:19

8-Jul-08 12:19

Sure, now this isn't the prettiest code - it's darn ugly, in fact. But it does work. I threw it into a Module but it's probably best suited for a class.

Imports System.Runtime.InteropServices

Module Module1

    Public Delegate Function EnumWindowsProc(ByVal hWnd As IntPtr, ByVal lParam As Integer) As Boolean
    <DllImport("user32")> Public Function EnumWindows( _
ByVal lpFunc As EnumWindowsProc, ByVal lParam As Integer) As Integer
    End Function

    Private Declare Auto Function GetWindowText Lib "user32" _
(ByVal hWnd As System.IntPtr, ByVal lpString As System.Text.StringBuilder, _ 
ByVal nMaxCount As Integer) As Integer
    Private Declare Auto Function FindWindowEx Lib "user32" _
(ByVal hWnd1 As IntPtr, ByVal hWnd2 As IntPtr, _ 
ByVal lpsz1 As String, ByVal lpsz2 As String) As System.IntPtr

    <Runtime.InteropServices.DllImport("user32.dll")> _
    Private Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Boolean
    End Function

    <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
      Private Function FindWindow( _
        ByVal lpClassName As String, _
      ByVal lpWindowName As String) As IntPtr
    End Function

    Public Function EnumWindowCBK(ByVal hWnd As IntPtr, ByVal lparam As Integer) As Boolean

        Static WindowText As New System.Text.StringBuilder(100)
        Static nRet As Long

        nRet = GetWindowText(hWnd, WindowText, WindowText.Capacity)
        If nRet <> vbNull Then

            If InStr(WindowText.ToString, "Notepad") <> 0 Then

                ' maximize it
                MsgBox(hWnd.ToString)
                ShowWindow(hWnd, 3)

            End If

        End If

        EnumWindowCBK = True

    End Function

End Module

Then whenever you want to maximize the window, call:

Module1.EnumWindows(New Module1.EnumWindowsProc(AddressOf EnumWindowCBK), 0)

It's pretty self-explanatory. EnumWindows gets all the desktop windows, and in the callback function EnumWindowCBK I compare the window's title with what we are looking for - it's up to you to decide if you only want the window text to match exactly or not. In this one, as long as it contains "Notepad" somewhere in there it will be maximized.

Sorry for not cleaning up that code better.

JLTBDY9-Jul-08 6:07

9-Jul-08 6:07

Hooooray!

Your help is greatly appreciated. I'm not a programmer, but with your help I accomplished building a screenPrint applet to call in one of our major apps.

I'm sure its not clean. but it does the job....
maximizes the host app,
then takes the snapshot,
puts it in a viewer for printing(with left edge cropped).

Big Grin | :-D

jzonthemtn10-Jul-08 3:17

10-Jul-08 3:17

Awesome! Glad I could help. Careful, or you'll become a programmer! Laugh | :laugh:

sql datareader

Ebube1-Jul-08 2:45

1-Jul-08 2:45

i hav a table wit one record i write the following code to retieve it and write to a file it works. but when i run as window service it does not write anything to the file. is there a better approach to i should use
Dim con As New SqlConnection("server=PRGLAP11;database = Diamond ;uid=sa;pwd=rr")

Dim con As New SqlConnection(connectionString)
Dim com1 As New SqlCommand(ins, con)
com1.CommandType = CommandType.StoredProcedure
con.Open()
Dim dr1 As SqlDataReader

dr1 = com1.ExecuteReader()

con.Close()

dr1.Read()
s1 = dr1.Item(1)
s2 = dr1.Item(2)
s3 = dr1.Item(3)
Dim f As New StreamWriter("c:\test2.txt")
f.Close()

paas1-Jul-08 3:26

paas

1-Jul-08 3:26

Did you check the event viewer on the system where the app is running as a service to see if any errors are being generated when it tries to create and write to a file?

When you set up the service, you must have had to set up a log on account for that service. I am wondering if maybe that log on does not have write permission to the drive or directory where you are writing the file. I don't think that would prevent the service from running, but I would expect it to generate some errors that are likely viewable via the event viewer.

Ebube1-Jul-08 5:05

1-Jul-08 5:05

actually the service is running my aim is to extract the information from database. it seems the reader does not retrn anyting. am using the file as my dubug technic. is ther a better way to debug

paas1-Jul-08 5:18

paas

1-Jul-08 5:18

Yes there is a better debug method for windows services. Check out the MSDN article at the following link, that should help...

How-to Debug Windows Service[^]

Ebube1-Jul-08 5:33

1-Jul-08 5:33

thanks i appreciate. will contact u if i hav more issue on that

Ebube1-Jul-08 6:04

1-Jul-08 6:04

i did what i read setting break point on the onstart method and it end sub when i pressed f10. it jumb to the line that instatiate timer if i press f10 again it show error that i acnot debug winservice
Protected Overrides Sub OnStart(ByVal args() As String)
' Add code here to start your service. This method should set things
' in motion so your service can do its work.
'System.Threading.Thread.Sleep(15000)
Try

t = New Timer(2000) 'stop here
't = New Timer(TimeInterval)

AddHandler t.Elapsed, AddressOf TimerFired
With t
.AutoReset = True
.Enabled = True
.Start()
End With
Catch ex As Exception
log.WriteEntry(ex.Message, EventLogEntryType.Information)
End Try
End Sub

paas1-Jul-08 7:03

paas

1-Jul-08 7:03

So you were able to attach to the process, move in to debug mode, but then it died on you? I'm not sure but that might be because debugging a service starting from OnStart can be problematic because if you spend too much time in OnStart, your service won't actually start. You might try putting a sleep right before you do your database connection, provided that is not in OnStart, and let OnStart run without any breaks. Then maybe you can get into debug mode before the connection happens and then step through the code from there.

Ebube1-Jul-08 16:09