Techie

Getting Expression Blend to open an Image in Fireworks / Photoshop, etc.

Mark Dryden — Wed, 23 Apr 2008 13:34:00 GMT

So firing up Expression Blend and getting into the whole WPF thing is always a refreshing change, especially getting away from mundane coding and alike. However, the first thing to trip me up and my colleague up was using the "Edit Externally" command from the project view to edit an existing '.png' file and whipping into my favourite graphics editor. Imagine my surprise when I was greeted with MSPaint! How there are two things to consider here...

I used to be a design guy prior to becoming a programmer, so MSPaint is the last thing I need to see.
Two - MSPaint is in no way anything like a sophisticated design application. Just get used to it ;-)

Now the doomsayers and conspiracy freaks might consider that MS has done this on purpose, so I fired up Reflector to work out how the project items (such as image files) were actually being catagorised and executed. What Blend does is by using the old .NET standby of Process.Start but explicitly passing through the 'Edit' string as the 'Verb' when making the call. In short, they're letting explorer handle the file association. Note: this works differently from explorer where if you double-click an existing and recognised dot extension it fires up the application with the selected file because its using the 'Open' verb and not the 'Edit' verb.

Ideally, Blend should use the 'Open' verb rather than hardcoding the 'Edit' verb (well, selection that is then implemented in the EditExternalCommand object) into the 'DocumentType.PreferredExternalEditCommand' property. Or even better - allow the user to specify those application they want for editing resources. But hey, its version 1.

So to get around this, a quick registry tweak will get things working. Navigate to the key...

HKEY_CLASSES_ROOT\SystemFileAssociations\image\shell\edit\command

...and change the value of the '(Default)' value to your favourite package from...

"%systemroot%\system32\mspaint.exe" "%1"

...to , so in my case to Fireworks...

"C:\Program Files\Macromedia\Fireworks 8\Fireworks.exe" "%1"

...and job done + no need restart...

HTH - And remember this fix / hack comes without warranty and will effect other instances where applications use this key as well. In short, be careful and backup your registry before doing this.

System.Net.Mail.SmtpClient not sending until the application exits

Mark Dryden — Wed, 26 Mar 2008 16:07:00 GMT

A very quick one. Been playing with the above class for generating emails in .NET 2.0, embedding images within HTML views which is rather cool. However, I noticed an unusual problem. The emails I generated in my test project would not send until I had exited the application. It was almost like it would only 'flush' the generated email once the application had unloaded. Interestingly, if I attempted to send the email using the 'SendAsync' method, it would fire the SendCompleted event but still nothing would come through until the application had ended.

The resolution? Turning off Symantec Anti-Virus's 'Internet Email Auto-Protect' facility from the 'Configure' menu. Once deselected, everything started behaving properly.

I cannot answer for any other AntiVirus packages - but its a good starting point if you're experiencing the above.

Disabling Flash (AxShockwaveFlash) Right-Click Context Menu

Mark Dryden — Mon, 03 Mar 2008 16:42:00 GMT

To be quite frank, after 3 months of ASP.NET development, the opportunity to do some down and dirty API programming really appealled to me today. So, the question (as indicated by the title) involved a member wanting to disable the right-click context menu from the Flash ActiveX component when being used in a WinForms application. (See previous blog entries for examples of Flash in VB.NET and communication between the two such as http://blogs.vbcity.com/drydo/archive/2005/10/18/5586.aspx).

The simple answer is to capture the right-click of the Flash Window itself and prevent it from being processed. A little play with Spy++ quickly came up with the answers and the rest was all about good old fashioned subclassing. I must admit it pinched the API declarations from Pinvoke.net and smartened them up a tad and that is pretty much it.

For the record, this is something I've been meaning to do for a while + I can leave work not feeling like some CSS floozy :)

Note: to recreate, create one form, one button and add one Flash Active X control. Copy and Paste as necessary. Tested in VS2005. If you get the dreaded 'Failed to import the ActiveX control' message, check out this workaround

Imports System.Runtime.InteropServices

Public Class Form1

#Region "API Routines"

    <DllImport("User32.dll")> _
   Private Shared Function EnumChildWindows _
       (ByVal WindowHandle As IntPtr, ByVal Callback As EnumWindowProcess, _
       ByVal lParam As IntPtr) As Boolean
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Sub GetClassName(ByVal hWnd As System.IntPtr, _
   ByVal lpClassName As System.Text.StringBuilder, ByVal nMaxCount As Integer)
    End Sub

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Overloads Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal
 nIndex As Integer, ByVal dwNewLong As Integer) As Integer
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Overloads Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal
 nIndex As Integer, ByVal dwNewLong As FlashCaptureRoutine) As Integer
    End Function

    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
     Private Shared Function CallWindowProc(ByVal lpPrevWndFunc As Integer, ByVal
 hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
    End Function

#End Region

#Region "Delegates"

    ' Used for processing Flash Window messages
    Public Delegate Function FlashCaptureRoutine(ByVal hwnd As Integer, ByVal
 Msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

    ' Used for enumerating child windows
    Public Delegate Function EnumWindowProcess(ByVal Handle As IntPtr, ByVal Parameter As IntPtr) As Boolean

#End Region

    ' Constants
    Public Const GWL_WNDPROC As Integer = (-4)
    Public Const WM_ENTERMENULOOP As Integer = &H211
    Public Const WM_RBUTTONDOWN As Integer = &H204
    Public Const WM_INITMENU = &H116

    ' Private vars
    Private mFlashWindowHandle As IntPtr
    Private mPreviousHandle As Integer
    Private isCapturing As Boolean

    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal 
e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        ' Cleanup if appropriate
        If isCapturing Then CleanupCapture()
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal 
e As System.EventArgs) Handles MyBase.Load
        ' Load the test movie...
        Me.AxShockwaveFlash1.Movie = "MyTestMovie.swf"
        Me.AxShockwaveFlash1.Menu = True
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal 
e As System.EventArgs) Handles Button1.Click
        ' Capture / Reset Flash Window Processing as appropriate

        ' React as approrpiate
        If isCapturing Then
            ' Resume
            CleanupCapture()
        Else
            ' Capture events
            CaptureRightClick()
        End If
        ' Switch over the flag
        isCapturing = Not isCapturing
    End Sub

    Private Sub CaptureRightClick()
        ' Attempt to obtain the Flash Window
        EnumChildWindows(Me.Handle, 
AddressOf EnumWindow, IntPtr.Zero)
        ' Subclass using new routine storing the old result
        mPreviousHandle = SetWindowLong(mFlashWindowHandle, GWL_WNDPROC, AddressOf FlashWindowCapture)
    End Sub

    Private Sub CleanupCapture()
        ' Reset back to the original handle...
        SetWindowLong(mFlashWindowHandle, GWL_WNDPROC, mPreviousHandle)
    End Sub

    Private Function FlashWindowCapture(ByVal hwnd As Integer, ByVal Msg As Integer, 
ByVal wParam As Integer, ByVal lParam As Integer) As Integer

        ' Capture the appropriate message and prevent it from being processed
        Select Case Msg
            Case WM_RBUTTONDOWN
                ' Exit
                Exit Function            
        End Select

        ' Carry on...
        Return CallWindowProc(mPreviousHandle, hwnd, Msg, wParam, lParam)
    End Function

    Private Function EnumWindow(ByVal Handle As IntPtr, ByVal Parameter As IntPtr) As Boolean
        ' Obtain the class name of the child window
        Dim ClassName As New System.Text.StringBuilder("", 255)
        GetClassName(Handle, ClassName, ClassName.MaxCapacity)

        ' Is this the Flash Window?
        If ClassName.ToString = "MacromediaFlashPlayerActiveX" Then
            mFlashWindowHandle = Handle
        End If
        Return True
    End Function

End Class

Strongly Typed Datasets (.NET 2.0) - Course Notes

Mark Dryden — Thu, 24 Jan 2008 09:55:00 GMT

This course was created for the VBCity Academy where you can take online courses for free. Unfortunately, the material I wrote is something I constantly want to keep linking to - so I've decided to place the course up as a flat article.

I fully recommend that the take the course through the Academy where the structure and flow of the course should make a little more sense - however, if big long documents are your thing - check out the article at http://blogs.vbcity.com/drydo/articles/8959.aspx.

CD, DVD and USB Key Insertion and Removal Detection

Mark Dryden — Wed, 10 Oct 2007 16:28:00 GMT

Just an old code snippet that I've dug out for a new project from an old VB6 project and thought it would be beneficial to post up but I start doing my VooDoo. In short, the following will detect the insertion and detection of USB key devices, CDs and DVDs. It doesn't detect the insertion of specific USB devices (at least not the devices arrayed in front of me) - but feel free to play with the code and the Hdr.devicetype parameter.

Anyhoo, create a new form and paste the following in...

Private Const WM_DEVICECHANGE As Integer = &H219

' Media Insertion parameters
Private Const DBT_DEVICEARRIVAL As Integer = &H8000
Private Const DBT_DEVICEREMOVECOMPLETE As Integer = &H8004&
Private Const DBT_DEVTYP_VOLUME As Integer = 2

' Media Insertion structures
<StructLayout(LayoutKind.Sequential)> _

Private Structure DEV_BROADCAST_HDR

Public size As Integer
Public devicetype As Integer
Public reserved As Integer

End Structure

<StructLayout(LayoutKind.Sequential)> _
Private Structure DEV_BROADCAST_VOLUME

Public Header As DEV_BROADCAST_HDR
Public UnitMask As Integer
Public Flags As Short

End Structure

Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)

' Capture the appropriate messages
Select Case m.Msg

Case WM_DEVICECHANGE

Dim Hdr As DEV_BROADCAST_HDR
Dim Volume As DEV_BROADCAST_VOLUME

' Perform conversion
Try

' Convert into the struct
Hdr = DirectCast( _

Marshal.PtrToStructure(m.LParam, Hdr.GetType), _
DEV_BROADCAST_HDR)

' If its an appropriate device, convert the volume type
If Hdr.devicetype = DBT_DEVTYP_VOLUME Then

Volume = DirectCast( _
Marshal.PtrToStructure(m.LParam, Volume.GetType), _
DEV_BROADCAST_VOLUME)

End If

Catch ex As Exception

Exit Sub

End Try

' Determine the event
Select Case m.WParam.ToInt32

Case DBT_DEVICEARRIVAL

MessageBox.Show("Inserted and ready on drive: " & GetVolumeLetter(Volume.UnitMask))

Case DBT_DEVICEREMOVECOMPLETE

MessageBox.Show("Removed from drive: " & GetVolumeLetter(Volume.UnitMask))

End Select

' Call the base routine
MyBase.WndProc(m)

End Sub

Private Function GetVolumeLetter(ByVal Mask As Integer) As Char

' This function takes the integer value passed through and determine the volume
' type that has been inserted/removed

Dim CharCode As Integer = 65
Do Until (Mask And 1) = 1

' Used instead of c# syntax of >>=
Mask = CType(Fix(CType(Mask, Double) / 2), Integer)
CharCode += 1

Loop
' Return the char val
Return Chr(CharCode)

End Function

This code comes without warranty so if it blows up, wipes your machine or becomes the key node in the birth of SkyNet - feel free to post a comment so I can laugh like a drain. Note: it does work but remember to include it within your testing phase...

Global Exception Handler for VB.NET

Mark Dryden — Tue, 02 Oct 2007 10:03:00 GMT

I've been involved in an interesting post where a member wanted to create a Global Exception Handler. As an absolute purist of course, I recommend that an adequate testing phase should eradicate virtually all errors, barring those that are effected by outside elements, e.g. FileSystem, Database(s), Networking, etc.

Anyhoo, we initially started off utilising the 'AppDomain.UnhandledException' event and whilst this certainly worked in the Development Environment, if it was ran as a normal executable as either the Debug or Release build - the CLR Error Handler would appear. After some research, I came across ex-MVP's Daniel Moth's Blog entry on the subject where the ThreadException event of the Application should also be captured along with a Try..Catch statement wrapped around the 'Application.Run' statement.

Anyhoo - the good news is that it worked (tested for Framework 2.0) and here's the code for those who are interested...

Module Startup

' Main display form
Private myStartupForm As Form1

' Delegate used to marshal back to the main UI thread
Private Delegate Sub SafeApplicationThreadException(ByVal sender As Object, ByVal e As Threading.ThreadExceptionEventArgs)

Sub Main()

' Initialise the startup form
myStartupForm = New Form1

' Configure the form...

' Configure AppDomain

Dim currentDomain As AppDomain = AppDomain.CurrentDomain
AddHandler currentDomain.UnhandledException, AddressOf AppDomain_UnhandledException
AddHandler Application.ThreadException, AddressOf Application_ThreadException

' Start the main form
Try

Application.Run(myStartupForm)

Catch ex As Exception

' Custom handling logic
DisplayCustomErrorLogic(ex)

End Try

End Sub

Private Sub DisplayCustomErrorLogic(ByVal sourceException As Exception)

' Hide the current form
myStartupForm.Hide()

' Display the message
MsgBox(sourceException.Message.ToString)

' Exit the application (you don't have to though)
Application.Exit()

End Sub

Private Sub Application_ThreadException(ByVal sender As Object, ByVal e As Threading.ThreadExceptionEventArgs)

' Pass to the safe exception handler
SafeApplication_ThreadException(sender, e)

End Sub

Private Sub SafeApplication_ThreadException(ByVal sender As Object, ByVal e As Threading.ThreadExceptionEventArgs)

' Are we running on the correct thread?
If myStartupForm.InvokeRequired Then

' Invoke back to the main thread
myStartupForm.Invoke(New SafeApplicationThreadException(AddressOf SafeApplication_ThreadException), New Object() {sender, e})

Else

' Custom handling logic
DisplayCustomErrorLogic(e.Exception)

End If

End Sub

Private Sub AppDomain_UnhandledException(ByVal sender As Object, ByVal e As UnhandledExceptionEventArgs)

' Custom handling logic
DisplayCustomErrorLogic(DirectCast(e.ExceptionObject, Exception))

End Sub

End Module

Note: the ThreadingException event is marshalled back to the main GUI thread, this allows any specific GUI manipulation with the original starting form if so desired. Note 2: in order to utilise the above code, create a new module called Startup and paste the above in. When completed, open the Project Properties up and select the 'Application' tab. Ensure that the 'Enable Application Framework' checkbox is unticked and then select 'Sub Main' from the Combobox titled 'Startup Object'.

Importing a TextFile into a Database using a Dataset

Mark Dryden — Fri, 28 Sep 2007 14:25:00 GMT

Importing a TextFile into a Database using a Dataset

This question comes up a bit on the forums (twice today already) where the user wants to import data from one Datasource (such as a TextFile) into a database (SQL Server / Access / Whatever). Now in the case of SQL Server my natural reaction would be to suggest DTS for SQL 2000 or check out some of the new cool features of SQL 2005 (which I've yet to experience). However, there are occasions - especially if some processing needs to be performing during the import, where it would be a lot easier if the import was done in .NET.

Now sure, if you want to read in your text file using a text reader - throw it into an array then utilise a DataCommand object and ExecuteNonQuery then go for it. However, if you like your coding a bit easier and find the DataTable a versatile object to store your data and perform various routine upon it before you upload, well, gather closer children...

OK - at my local pub they run a Bonus Ball thing. Basically, everyone has a number and pays one pound per week for privilege of that number. If the said number comes out in the National UK Lotto as the Bonus Ball on a Saturday, then you win the lot (up to £49). Now there's a lot of banter about who keeps winning (or seems to keep winning) and those with sob stories about how they haven't won in 'x' number of years. So on occasion I grab all the results from a website (Lottery Results) throw it into SQL and run a quick GROUP BY query to work out exactly when people have won.

So - for this post I've taken the results of the page and saved it as a text file. Got rid of the 'UK National Lotto Winning Numbers' and the 'All lotteries below have exceeded the 180 days expiry date' strings and second set of field titles just below this (maintaining the first line with the field names) and there's my text file for import.

I place the text file into an appropriate directory, create my table in a test Database, structure as is...

CREATE TABLE [dbo].[tblLottery] (

[EntryId] [int] IDENTITY (1, 1) NOT NULL ,
[LotteryId] [int] NOT NULL ,
[BonusBall] [int] NOT NULL ,
[WeekDay] [nvarchar] (3) COLLATE Latin1_General_CI_AS NOT NULL ,
[DrawDay] [int] NOT NULL ,
[DrawMonth] [nvarchar] (10) COLLATE Latin1_General_CI_AS NOT NULL ,
[DrawYear] [int] NOT NULL

) ON [PRIMARY]

and then utilise my code...

' Dataset

Dim ds As New DataSet

' Text File connection
Dim oleTextConn As New OleDbConnection
' Set the connection string
oleTextConn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\MyImportDirectory\;Extended Properties=""text;HDR=Yes;FMT=Delimited"""

' Configure a dataadapter to load in the text data into my dataset
Dim daTextFile As New OleDbDataAdapter
' Generate the Select Command
Dim selCommand As New OleDbCommand
' Configure
With selCommand

.CommandText = "SELECT * FROM [Lottery.txt]"
.CommandType = CommandType.Text
.Connection = oleTextConn

End With
' Add to the dataadapter
daTextFile.SelectCommand = selCommand

' Fill the dataset
oleTextConn.Open()
daTextFile.Fill(ds)

' Cleanup our text connections
oleTextConn.Close()
daTextFile.Dispose()
daTextFile = Nothing
oleTextConn.Dispose()
oleTextConn = Nothing

' Create the SQL Connection
Dim sqlConn As New SqlConnection
sqlConn.ConnectionString = "Data Source=ARNIE;Initial Catalog=MyLotteryDB;Integrated Security=SSPI;"
' Create a new SQL DataAdapter
Dim daSQL As New SqlDataAdapter
' Generate the Insert Command
Dim insCommand As New SqlCommand
With insCommand

.CommandText = "INSERT INTO tblLottery ( [LotteryId] , [BonusBall] , [WeekDay] , [DrawDay] , [DrawMonth] , [DrawYear] ) VALUES ( @LotteryId , @BonusBall , @WeekDay, @DrawDay , @DrawMonth, @DrawYear )"
.CommandType = CommandType.Text
.Connection = sqlConn

' Configure the insert parameters
.Parameters.Add(New SqlParameter("@LotteryId", SqlDbType.Int, 0, "No#"))
.Parameters.Add(New SqlParameter("@BonusBall", SqlDbType.Int, 0, "BN"))
.Parameters.Add(New SqlParameter("@WeekDay", SqlDbType.NVarChar, 3, "Day"))
.Parameters.Add(New SqlParameter("@DrawDay", SqlDbType.Int, 0, "DD"))
.Parameters.Add(New SqlParameter("@DrawMonth", SqlDbType.NVarChar, 10, "MMM"))
.Parameters.Add(New SqlParameter("@DrawYear", SqlDbType.Int, 0, "YYYY"))

End With
' Add to the dataadapter
daSQL.InsertCommand = insCommand

' Loop through each row and set its rowstate to added
' This will cause the dataadapter to think every row is new and needs inserting...
For Each dr As DataRow In ds.Tables(0).Rows

dr.SetAdded()

' Open the SQL Connection and Update
sqlConn.Open()
daSQL.Update(ds.Tables(0))

' Cleanup
sqlConn.Close()
daSQL.Dispose()
daSQL = Nothing
sqlConn.Dispose()
sqlConn = Nothing

...and job done. Takes around 3 seconds to process on my machine which is pretty slick huh?

Design Notes:

If you are not familiar with the Text File OleDb Driver, you specify the directory only in the connection string then the actual filename in the SELECT statement. In other words, each text file should be classed as its own data entity.
When a datarow is loaded into a dataset, it rowstate will be set with the 'Unchanged' flag. If we then run our SQLDataAdapter nothing will happen as the dataset knows that the records have not been altered. In order for them to be inserted we reset this flag to 'Added' that will invoke the 'InsertCommand' when the 'Update' routine is called.
Note: I use the 'SetAdded' method of the DataRow object to set the DataRow's RowState. This is a Framework 2.0 method only. But this can be worked around for Framework 1.*, e.g. create a duplicate DataTable and 'Add' the records from the sourcetable to new table - this should set the RowState flag.

HTH - M

ASP.NET 2.0, Custom Role assignment without a 'Role Provider'

Mark Dryden — Wed, 19 Sep 2007 11:18:00 GMT

I love starting new projects with a new technology and recently the requirement for an ASP.NET 2.0 custom reporting module landed on my desk. I have some ASP.NET 1.1 experience having created a couple of sites about two years ago but that was it.

Keen to implement some of ASP.NET 2.0's cool features I came across the Membership, Roles and Profiles features @ http://www.4guysfromrolla.com and was impressed by how easy it was to generate a robust authentication system from scratch utilising Roles and various other niceities. However, out of all these articles there didn't seem to be anything that covered the scenario where the developer had already got a database and structure for storage and a library that could handle the authentication, role assignment and various other tasks.

Digging a little deeper it seemed that I could still utilise the login control then capture the 'authenticate' event and then employ my custom logic to authenticate the user. However, I wanted an easy way to identify whether the user was part of a specific role or not.

Now I must admit I checked out creating my own custom 'Role Provider' and whilst this might have been a better approach (especially if I wanted to expose routines to Add, Remove, Amend roles from a user) in the scenario where I'm handling this elsewhere - it seemed to be overkill.

Anyhoo, here's how I did it...

In my 'Authenticate' event of the login control I instantiate my custom authentication class. In my case, this class exposes a method to authenticate the user (returning a boolean value) and a property exposing the role of the user (which is a numerical value).

Note: it is possible of utilise multiple roles, my scenario precluded that option...

Here's the psuedo-code....

' Custom authentication class

Dim myAuthentication As New UserAuthentication

' Call custom authentication routine (where: conLogin is the Login control)
' and pass the username and password over
If myAuthentication.AuthenticateUser(conLogin.UserName, conLogin.Password) Then

' If sucessful, generate the authentication ticket
Dim ticket As New FormsAuthenticationTicket( _

1, _
"userName", _
DateTime.Now, _
DateTime.Now.AddMinutes(20), _
False, _
myAuthentication.RoleId, _ ' Retreive the RoleId from the authentication class
FormsAuthentication.FormsCookiePath)

' Encrypt
Dim encTicket As String = FormsAuthentication.Encrypt(ticket)
Dim authCookie As New HttpCookie(FormsAuthentication.FormsCookieName, encTicket)

' Add to the cookies
Response.Cookies.Add(authCookie)

' Perform any appropriate navigation from the login page
Response.Redirect("NextPage.aspx")

End If

As you can see when I instantiate my AuthenticationTicket I pass the RoleId into the 'userData' argument. Once in there, I can now utilise that value elsewhere, namely the HttpApplication.AuthenticateRequest event where I can parse the current FormsIdentity, obtain the appropriate RoleId from the 'userData' property and add that to the 'roles' for the current user.

So, if you haven't created a Global.asax file, do so. Within here you need to capture the 'AuthenticateRequest' event of the Application object and then utilise the following code...

Protected Sub Application_AuthenticateRequest(ByVal sender As Object, ByVal e As System.EventArgs)

' Does the object exist and is the user instantiate?
If (((Not HttpContext.Current.User Is Nothing) AndAlso HttpContext.Current.User.Identity.IsAuthenticated) AndAlso TypeOf HttpContext.Current.User.Identity Is FormsIdentity) Then

' Retreive the current identity
Dim id As FormsIdentity = CType(HttpContext.Current.User.Identity, FormsIdentity)
' Reset the User object and incorporate the new roles
HttpContext.Current.User = New System.Security.Principal.GenericPrincipal(id, New String() {id.Ticket.UserData})

End If

End Sub

So the User object is reset with the appropriate role. Note: that the 'roles()' argument of instantiation of 'GenericPrincipal' object does accept an array of string to support multiple roles.

Now, it is possible to utilise the base 'User.IsInRole' method and pass the appropriate RoleId over. However, I tend to make my job slightly easier by employing an Enum and utilising that, e.g.

If User.IsInRole(Constants.UserRoles.Administrator) Then

Response.Write("You're an Administrator!")

Else

Response.Write("You're a nobody.")

End If

And that's it. One block of code in the Global.asasx and one Enum to make coding slightly easily (admittedly without Option Strict On) and everything is up and running!

HTH - M

Deleting Files using Array.ForEach (My Generics Enlightenment)

Mark Dryden — Wed, 25 Jul 2007 14:11:00 GMT

Just a tiny post after another break of sorting out the house selling junk on eBay.

Today I saw a post on the VbCity Forums where the ORPO wanted to delete a portion of files from a directory using a search pattern. The answer was to utilise the 'IO.Directory' or 'IO.DirectoryInfo' class's 'GetFiles' method then loop through the result deleting the appropriate 'IO.File' or 'IO.FileInfo' object. However, ORPO's being ORPO's wanted to perform this action in one line.

Anyhoo, after coming to the end of my lunch I decided to trawl the intellisense to see if anything jumped out at me. And it did :-)

Now I have to admit that I thought that Generics (introducing with .NET 2.0) was merely a matter of strongly typing Arraylists - however, introductions to the likes of anonymous methods have left me thinking that it can a bigger and more impactive part of the framework that originally thought (at least from a coding perspective).

So - back to the chase. The 'Array' object has a shared method called 'ForEach' that will loop through the array performing the specified function upon each object (identified using a delegate). So - all I had to do was get the list of files and pass the hard work over to the 'IO.File.Delete' method....

' Deletes all files with the extension of '.doc' under the 'MyDirectory' directory.
Array.ForEach(Of String)(IO.Directory.GetFiles("C:\MyDirectory\", "*.doc"), AddressOf IO.File.Delete)

Cool huh?

.NET Micro Framework - Further thoughts...

Mark Dryden — Thu, 24 May 2007 10:48:00 GMT

Well, it's been a fun couple of days messing with the Micro Framework and overall I'm impressed. Sure - the .NET Micro Framework doesn't have the XML namespace, but it is a *Micro* framework people.

Anyhoo, I've managed to code up some simple applications such as an image viewer that could move between image, which I then improved so it moved between images and used an alpha transition between each one. And I've also been messing the SerialPort class to just send some simple commands to our RS232 relay board - the plan is to get an RS232 IR transmitter so we can communicate with Kevin our RoboSapien2 so fingers crossed.

From all that playing around, here are a couple of titbits...

Debugging live from the actual board. Sussed out that this wasn't a limitation but rather that Visual Studio SP1 had 'lost' the configuration manager from the Project Properties and Dropdown combo from the Build menu bar. Anyhoo, to get it back simply goto 'Tools', 'Options', navigate to 'Projects and Solutions' and ensure that 'Show advanced build configurations' is checked! Then it was a matter of setting the configuration manager to 'Build' and 'Deploy'!
For some reason the Tahoe board completely crapped out on me big time. Basically, my application would start up but then overwrite on the display with 'ABORT data' and output the some various debug data / registers (that could be navigated using the 'Up' and 'Down' buttons). Not a problem you would think? Well, it seems that the 'ABORT data' left the board is a non-interruptible state and therefore I could no longer deploy again to the device.

OK - I panicked. I tried everything to get the board back up and running and the only way I got it (after an hour messing with the board, swapping out and installing the USB drivers) was to reset the actual board at the moment when the deploy actually took place. Whether this actually solved the problem remains to be seen - I couldn't tell through the blurred tears.
Finally, a little bit of code on resizing an image and displaying it (in this case to the dimensions of the screen). My first natural instinct was to ensure that the bitmap object had an appropriate routine (there called 'Bitmap.StretchImage') - however, it came with the 'Remark' that the method was for backward compatibility, etc. So, here's my attempt at demonstrating the old technique (StretchImage) and one new technique. Enjoy...

(Note: and remember to remove the 'System.Drawing' namespace from your assembly when adding images as resources!)

Utilising an Image Brush and Rectangle

/// <summary> Constructor for the window</summary>
public MainViewWindow()
{
// panel control to fill the window client area
Panel panel = new Panel();
panel.HorizontalAlignment = HorizontalAlignment.Stretch;
panel.VerticalAlignment = VerticalAlignment.Stretch;
// Generate a bitmap and obtain from the resource
Bitmap bOriginal = Resources.GetBitmap(Resources.BitmapResources.MyResourceImage);
Bitmap bResized = new Bitmap(SystemMetrics.ScreenWidth, SystemMetrics.ScreenHeight);
// Resize the image
bResized.StretchImage(0, 0, bOriginal, bResized.Width, bResized.Height, 255);
// Generate an image control and set with the resized image
Image img = new Image(bResized);
// Add the image to the main panel
panel.Children.Add(img);
// The window has exactly one child
this.Child = panel;
}

Utilising an Image Brush and Rectangle

/// <summary> Constructor for the window</summary>
public MainViewWindow()
{
// panel control to fill the window client area
Panel panel = new Panel();
panel.HorizontalAlignment = HorizontalAlignment.Stretch;
panel.VerticalAlignment = VerticalAlignment.Stretch;
// Create an image brush with the bitmap from resource
ImageBrush imgBrush = new ImageBrush(Resources.GetBitmap(Resources.BitmapResources.MyResourceImage));
// Ensure it will fill the parent
imgBrush.Stretch = Stretch.Fill;
// Generate a rectangle
Microsoft.SPOT.Presentation.Shapes.Rectangle rect = new Microsoft.SPOT.Presentation.Shapes.Rectangle();
// Configure (e.g. lose the stroke border)
rect.Stroke = new Pen( Color.White , 0);
rect.Fill = imgBrush;
// Add the image to the main panel
panel.Children.Add(rect);
// The window has exactly one child
this.Child = panel;
}

Note: the above code is just test / development code - no picking through my clumsy C# :p

Have fun - M