John Koerner's Page

Creating a Firewall Exception in VB.Net

2009-12-22T03:30:46Z

Windows Vista and 7 provide a rather robust firewall API that can be used to add exceptions to the firewall. The code below will add an exception to the windows firewall for the specified application, provided that the code is run with administrator privileges. Add a reference to %systemroot%\system32\FirewallAPI.dll to your application.

Imports NetFwTypeLib
Public Class Form1

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

        ' Create the Application we want to add to the exception list
        Dim appType As Type = Type.GetTypeFromProgID("HnetCfg.FwAuthorizedApplication")
        Dim app As INetFwAuthorizedApplication
        app = DirectCast(Activator.CreateInstance(appType), INetFwAuthorizedApplication)

        ' Set the application properties
        app.Name = "Negative0's Sandbox"
        app.ProcessImageFileName = "C:\Users\Negative0\vbsandbox2.exe"
        app.Enabled = True

        ' Get the firewall manager, so we can get the list of authorized apps
        Dim fwMgrType As Type = Type.GetTypeFromProgID("HnetCfg.FwMgr")
        Dim fwMgr As INetFwMgr
        fwMgr = DirectCast(Activator.CreateInstance(fwMgrType), INetFwMgr)

        ' Get the list of authorized applications from the Firewall Manager, so we can add our app to that list
        Dim apps As INetFwAuthorizedApplications
        apps = fwMgr.LocalPolicy.CurrentProfile.AuthorizedApplications
        apps.Add(app)

    End Sub

End Class

Colorized by: CarlosAg.CodeColorizer

Find Pixels on the screen by color without using GetPixel API.

2009-11-30T03:27:00Z

Occasionally I need to write an app that reads pixels from the screen. When searching small chunks of the screen, the windows GetPixel API works fine, but if I need to search the whole screen, that gets too slow. One way that I have found that is about twice as fast as GetPixel is copying the screen to a bitmap and using the Bitmap's GetPixel method. Below is an extension method that works with the Screen class to find pixels.

Module ScreenExtensions
     _
    Public Function FindPixelsByColor(ByVal CurrentScreen As Screen, ByVal SearchColor As Color) As List(Of Point)

        Dim ScreenBitmap As Bitmap = Nothing
        Dim ScreenCopier As Graphics = Nothing

        If CurrentScreen Is Nothing Then Throw New ArgumentException("The screen object is nothing.")
        If SearchColor = Color.Empty Then Throw New ArgumentException("The search color is empty.")

        Try
            ' Initialize our output of points.
            Dim OutputPoints As New List(Of Point)

            ' Create the bitmap object that will be used to store the image of the screen.
            ScreenBitmap = New Bitmap(CurrentScreen.WorkingArea.Width, CurrentScreen.WorkingArea.Height, _
                         Imaging.PixelFormat.Format32bppArgb)

            ' Create the graphics object that will be used to copy the screen
            ScreenCopier = Graphics.FromImage(ScreenBitmap)

            ' Copy from the screen to the bitmap, so we can search for the pixels we are looking for
            ScreenCopier.CopyFromScreen(New Point(0, 0), New Point(0, 0), _
                    New Size(CurrentScreen.WorkingArea.Width, CurrentScreen.WorkingArea.Height))

            Dim ScreenColor As Color

            ' Loop through all of the pixels in the bitmap
            For x As Integer = 0 To CurrentScreen.WorkingArea.Width - 1
                For y As Integer = 0 To CurrentScreen.WorkingArea.Height - 1
                    ' Get the color at the current pixel from the screenshot.
                    ScreenColor = ScreenBitmap.GetPixel(x, y)

                    ' Compare the color from the screenshot with the desired color.  We need to level off the alpha
                    ' for this compare to work properly.  All colors from the screenshot have an alpha of 255.
                    If ScreenColor = Color.FromArgb(255, SearchColor) Then
                        ' If we have a match, then add the current x,y to our output.
                        OutputPoints.Add(New Point(x, y))
                    End If
                Next

            Next

            Return OutputPoints
        Catch ex As Exception
            Throw New Exception("Unable to perform pixel search.", ex)
        Finally

            If ScreenBitmap IsNot Nothing Then ScreenBitmap.Dispose()
            If ScreenCopier IsNot Nothing Then ScreenCopier.Dispose()
        End Try
    End Function
End Module

Colorized by: CarlosAg.CodeColorizer

To use this class. You can simply call it from any screen object. For example:

        Dim l As List(Of Point)

        l = Screen.PrimaryScreen.FindPixelsByColor(Color.FromArgb(128, 128, 128))

        MessageBox.Show(l.Count.ToString())

Colorized by: CarlosAg.CodeColorizer

Taking a screenshot in VB.Net

2009-03-14T17:24:00Z

Taking a screenshot from a .Net app is very easy. The function to use is the CopyFromScreen function from the Graphics class.

        Dim b As Bitmap

        'Hide the form, so it doesn't show in the screenshot
        Me.Hide()

        b = New Bitmap(My.Computer.Screen.WorkingArea.Width, _
                My.Computer.Screen.WorkingArea.Height, _
                Imaging.PixelFormat.Format32bppArgb)
        Dim g As Graphics = Graphics.FromImage(b)
        g.CopyFromScreen(New Point(0, 0), New Point(0, 0), _
                New Size(My.Computer.Screen.WorkingArea.Width, _
                 My.Computer.Screen.WorkingArea.Height))

        'Show the form again
        Me.Show()

        'Save the file
        Dim ofd As New SaveFileDialog ()
        ofd.Filter = "(*.bmp)|*.bmp"
        If ofd.ShowDialog() = Windows.Forms.DialogResult.OK Then
            b.Save(ofd.FileName)
        End If

Colorized by: CarlosAg.CodeColorizer

Using the ShowWindow API on a VB6 App from .Net

2009-02-13T03:14:00Z

I was helping someone with an issue restoring vb6 windows from a .Net application over on VBForums. The issue ended up being that the MainWindowHandle of the process was returning the window handle for the ThunderRT6Main window. The ThunderRT6Main is a hidden window that all VB6 apps have that is used for message processing. When we called ShowWindow against this window handle, nothing would happen. To get around this, I ended up calling the GetWindow API with a GW_HWNDPREV to get the window handle of the form window and then called ShowWindow on that.

Private SW_SHOWNORMAL As Integer = &H1
    "user32", EntryPoint:="ShowWindow")> _
    Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Integer) As Integer
    End Function

    Declare Auto Function GetWindow Lib "user32.dll" ( _
ByVal hWnd As IntPtr, ByVal uCmd As UInt32) As IntPtr

    Const GW_HWNDPREV As Integer = 3

    Dim proc As New Process

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

        ' Start the process
        With proc
            .StartInfo.FileName = "c:\temp\project1.exe"
            .Start()
        End With

        ' Wait for it to finish loading and put the window handle into the form caption
        proc.WaitForInputIdle(10000)
        Me.Text = proc.MainWindowHandle.ToString("x8")

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ' Call GetWindow with GW_HWNDPREV to get the form from the ThunderRT6Main window
        Dim vb6Window As IntPtr = GetWindow(proc.MainWindowHandle, GW_HWNDPREV)

        ' Call ShowWindow on the window we got back from the last call, which should be the ThunderRT6FormDC window
        ShowWindow(vb6Window, SW_SHOWNORMAL)

    End Sub

Keyboard Listener

2008-11-24T20:30:28Z

Whenever I need to write a keyboard listener, I always have to go back and search through old code to get the exact syntax. I then end up copying and pasting a whole bunch of code. I decided it was time to create a DLL that will handle all of this work for me. I also decided that I will post the DLL up here for anyone to use as they see fit.

The DLL is copyrighted, however, it is free for distribution with personal or commercial applications.

The setup package, which includes a help file, a sample app, and the DLL, can be downloaded from the downloads page, or from the link below.

Download: KeyboardListener.msi

The sample app shows off the basic functionality of listening for one particular key, a set number of keys, or all key presses on a system. Below is a screenshot of the sample application. This dll works system wide, not just within the application that is using it.

Creating a Plugin Architecture in C#

2008-07-21T23:22:00Z

Creating a plugin architecture in a C# application is a fairly easy task. The video below will walk you through the process of setting up the plugin architecture and it will implement a simple plugin.

The source for the project can be downloaded Here.

Conditionally Formatting ComboBox Items in C#

2008-07-09T02:54:41Z

The video below gives an overview of creating a ComboBox that does conditional formatting. The code uses regular expressions to determine if an item in a combobox should have special formatting. The code is nowhere near production ready, but it should give you an idea of how to do formatting of items in a combobox drop down list. See the full post if you want to copy the code.

Continue reading "Conditionally Formatting ComboBox Items in C#"

New Download Available

2008-06-12T03:55:08Z

I have added a SCORM compliant version of the Creating Content for the SharePoint Learning Kit video to the downloads page if you would like to have a copy of it in your own SharePoint site.

Creating Content for the SharePoint Learning Kit

2008-06-10T03:36:15Z

Here is a new video demonstrating how to create SCORM content for the SharePoint Learning Kit.

Resources:
SCORM Simple Content API
Jing Project
SharePoint Learning Kit

MOSS: Adding sub navigation

2008-05-17T20:42:59Z

I found a nice little post from Heather Solomon on allowing SharePoint to have multiple levels of sub navigation. It works really well, but the navigation editor in MOSS does not let you nest sub-menus by default. I wrote a quick little C# app that allowed me to add navigation as needed. Here is the meat of the code.

SPNavigationNode oNewNode = new SPNavigationNode("My New Tab3","");
oWeb.Navigation.TopNavigationBar.AddAsLast(oNewNode);
oNewNode.Properties.Add("NodeType","Heading");
oNewNode.Update();

SPNavigationNode oChild1 = new SPNavigationNode("C1","/");
oNewNode.Children.AddAsFirst(oChild1);
oChild1.Properties.Add("NodeType","Heading");
oChild1.Update();

SPNavigationNode oChild2 = new SPNavigationNode("C2","/");
oChild1.Children.AddAsFirst(oChild2);

Note: I have only tested this on MOSS 2007 and it did some weird things to my tab highlighting that I haven't figured out yet.

Visual Studio Extensions for Sharepoint - ListDefinition1

2008-04-20T15:46:03Z

If you have used the Visual Studio Extensions for Sharepoint to create more than one list, then you will probably be familiar with the problem of all custom List Definitions are given the name ListDefinition1. This causes problems when you activate the feature, because SharePoint already thinks ListDefinition1 exists.

To fix this problem, there are a few things that need to be changed in your project.

1.) Rename the ListDefinition1 folder in your solution.
2.) Change the URL in the Instance.XML. You'll probably want to change the display name as well, but that is not necessary.
3.) Change the Name in the ListDefinition.xml. Again, you'll probably want to change the display name as well.

Some things to keep in mind are that the display name column is used in one of the folder names that is created by the extensions, so if you use a character that SharePoint doesn't like (i.e. an apostrophe) you will get an error.

If you get an error when deploying, your best bet is to fix the error in VS, delete the PKG folder, and then rebuild and deploy your solution.

MOSS XSL for ItemStyles

2008-04-17T16:33:13Z

I found a nice little snippet on Heather Solomon's site for customizing the CQWP. She had a nice little debugging XSL style for items to see what properties were available.

After doing a little digging with the XSL, I enhanced it just a bit, so I could get both the parameter name and the value:

<xsl:template name="Debug" match="Row[@Style='Debug']" mode="itemstyle">
<xsl:for-each select="@*">
P:<xsl:value-of select="name()" />=<xsl:value-of select="."/> <br />
xsl:for-each>
xsl:template>

The output then looks like:

P:ListId=FF486727-3DD6-4FFB-A5F5-B9A922366E9E
P:WebId=FF7C38FA-BBAA-4240-9A2B-63B8F508C780
P:ID=1
P:x007B_ff564e0f_x002D_0c70_x002D_4ab9_x002D_b863_x002D_0177e6ddd247_x007D=Welcome to your Project Diary!
P:FileRef=Customers/Customer1/CustomerProject/Lists/Posts/1_.000
P:x007B_ff22ea11_x002D_1e32_x002D_424e_x002D_89ab_x002D_9fedbadb6ce1_x007D=1
P:Modified=2008-03-25 12:50:55
P:Author=System Account
P:Editor=System Account
P:Created=2008-03-25 12:42:02
P:PublishingRollupImage=

Showing Items Without Folders in the DataView Web Part

2008-04-04T00:09:00Z

I have a dataview web part (aka dataform web part) pointed to a list with items that are all in sub folders. By default the web part displays just the items from the root folder. I did some searching on the net and found people had this problem with CAML queries and that they had to set the Scope property of the query to Recursive. Since I was doing this through the SharePoint designer, I had to figure out where to set the property. To save everyone else (and myself in the future) some time, here is how I did it:

Open up the page in split or code view. Scroll to the SharePoint:SPDataSource object inside of your DataFormWebPart.

Click somewhere inside the SPDataSource tag. This will bring up the tag properties window on the left. From here you can set your scope property.

The four properties are documented in the MSDN library in the SPViewScope enumeration.

MOSS - The specified account name is invalid

2007-12-20T18:35:02Z

I have been building a Virtual Machine for my MOSS development and testing. I had not configured active directory on the machine, but one piece of software required it for me to continue. So I setup my machine as a domain controller and created a domain called VMDomain. This worked and everything seemed fine. I then went to do some work in sharepoint and noticed that some features were erroring out. I checked the event viewer and had quite a few messages in there stating "The specified account name is invalid." I also had other errors about usernames not mapping to security IDs. I was positive that this was something that had been broken because of the domain change. I changed accounts on services, application pools, and anything else I could find, but I was still getting those errors every few minutes.

I googled the errors I was getting, but didn't really get any good results. Finally, I was messing around in central admin, when I noticed one screen that I had not been in yet. Under the operations tab, under the Security Configurations group, the Service Accounts item. I selected Web Application Pool and then selected the Sharepoint - 80 app pool and modified the ID and password. After making the update, all of my event viewer errors seemed to go away.

Powershell Stopwatch

2007-12-04T01:14:26Z

So I needed a stopwatch today to time a project I was working on, so I decided to write a quick PS script to do it for me:

function global:StopWatch()
{
  # Create the stopwatch
  [System.Diagnostics.Stopwatch] $sw;
  $sw = New-Object System.Diagnostics.StopWatch
  $sw.Start()
  write-host "Press enter to stop..."
  # Wait for input, and we will just disregard anything they type
  $blah = read-host
  $sw.Stop()

  # Write the compact output to the screen
  write-host $sw.Elapsed.ToString()

  # Write verbose output to screen
  #write-host "Days:" $sw.Elapsed.Days.ToString()
  #write-host "Hours:" $sw.Elapsed.Hours.ToString()
  #write-host "Minutes:" $sw.Elapsed.Minutes.ToString()
  #write-host "Seconds:" $sw.Elapsed.Seconds.ToString()
  #write-host "Milliseconds:" $sw.Elapsed.Milliseconds.ToString()
}