October 2009 - Posts

• Silverlight 3 - Enabling the Silverlight 'Out of Browser' Experience

  Silverlight 3 applications can be installed as local applications on PCs and MACs. This is a brief 'how to' for enabling, installing, and removing a Silverlight 3 out of browser applications. 1. Use Visual Studio 2008 or 2010 to create a Silverlight 3 project. 2. Open the Silverlight 3 project's properties dialog. Select the 'Silverlight' tab. Check the 'Enable running application out of the browser'. Click the 'Out-of-Browser Settings...' button. 3. The 'Out-of-Browser Settings' dialog opens. Use it to configure your Silverlight 3 application for out of browser installation. 4. Run your application.  Right-click a page in your application and select 'Install..' menu item. 5. The 'Install application' dialog opens. Use it to install short cuts to your application. 6. The Silverlight 3 out of browser application short cut on the desktop: 7. Use the short cut to launch the application on the computer. Here's a screen shot of my sample application running locally on my computer: 8 To remove the Silverlight 3 out of browser application from your computer: run it, right-click a page in the application, and select the 'Remove this application...' menu item. Posted Oct 23 2009, 06:09 AM by Mike McIntyre

• Visual Basic 2010 and .NET Framework 4 Deliver Beta 2 in Final Stretch to March 22 Launch

  Read all about it at:  Final Stretch Posted Oct 20 2009, 07:44 AM by Mike McIntyre

• Search for Files with a Specific Extension in and below a System Special Folder

  The Visual Basic My.Computer.FileSystem GetFiles method can be used to search for files with a specific extension in or below a specific directory: Below is a function for that purpose:     Private Function GetFilePathList(ByVal specialDirectoryPath As String, ByVal fileExtension As String) _                     As List(Of String)         ' Instantiate a list of type String.         Dim filePathList As New List(Of String)         ' Use the My.Computer.FileSystem GetFiles method to search for files with a specific file         '   extension in or below a specific directory.         ' Note the use of the FileIO.SearchOption SearchAllSubDirectories to request all directories         '   below the specifified directory be searched too.         For Each filePath As String In My.Computer.FileSystem.GetFiles(specialDirectoryPath, _                     FileIO.SearchOption.SearchAllSubDirectories, fileExtension)             filePathList.Add(filePath)         Next         Return filePathList     End Function Here's an example show how to call the function above: Dim fileList As List(Of String) = GetFilePathList(My.Computer.FileSystem.SpecialDirectories.MyPictures, "*.png")   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 14 2009, 07:19 PM by Mike McIntyre Filed under: GetFiles

• Validation and the Windows Forms ErrorProvider

  Download source code here ->  Validation and the Windows Forms ErrorProvider Component I've noticed that not a lot of people take advantage of the Windows Forms built in user interface for indicating that a control on a form has an error associated with it - the ErrorProvider component. The ErrorProvider presents a simple mechanism for indicating to the end user that a control on a form has an error associated with it. If an error description string is specified for the control, an icon appears next to the control. The icon flashes in the manner specified by BlinkStyle, at the rate specified by BlinkRate. When the mouse hovers over the icon, a ToolTip appears showing the error description string. Typically, you use ErrorProvider in association with data-bound controls. When using ErrorProvider with data-bound controls, you must specify the ContainerControl, either in the constructor or by setting the ContainerControl property. The Visual Studio project download at the link above demonstrates how to combine validation with the ErrorProvider.   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 10 2009, 08:03 PM by Mike McIntyre Filed under: WindowsForms, ErrorProvider

• Visual Basic 2010 - Nullable Optional Parameters

  Nullable types were a welcome addition to Visual Basic 2008.  In Visual Basic 2010 you can use them as parameters.  Here are two examples:     ' Assign Nothing as the default value for nullable optional parameter.     Sub Add(ByVal x As Integer, ByVal y As Integer, Optional ByVal z As Integer? = Nothing)         ' code removed for brevity     End Sub       ' Assign an integer value to a nullable optional paramter of type Double.     Sub Process(ByVal x As Integer, ByVal y As Integer, Optional ByVal z As Double? = 4)         ' code removed for brevity     End Sub   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 10 2009, 01:40 PM by Mike McIntyre Filed under: visual basic 2010, nullable optional parameters

• Visual Basic 2010 - Array Literals

  Visual Basic 2010 array litererals provide a shortcut mechanism for declaring and filling arrays for types that can be inferred by the compiler.  Here a three examples:         ' Examples         Dim a = {1, 2, 3} 'infers Integer()         Dim b = {1, 2, 3.5} 'infers Double()         Dim c = {"1", "2", "3"} 'infers String() Becareful not to mix in types the compiler can not infer:          ' WARNING: Make sure you used types that can be inferred.         ' The next example will generation a warning if OPTION STRICT ON         '   or infer a type of Object if OPTION STRICT OFF         Dim d = {1, "123"} 'infers Object() (warning with Option Strict On) Create multidimensional arrays with array literals:         ' Create multidimensional arrays by nesting array array literals:         'Nested array literals can be used to produce multidimensional arrays:         Dim f = {{1, 2, 3}, {4, 5, 6}} 'infers Integer(,)         Dim g = {({1, 2, 3}), ({4, 5, 6})} 'infers Integer()() (jagged array)   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 08 2009, 01:30 PM by Mike McIntyre Filed under: visual basic 10, Visual Studio 2010, array literal

• Visual Basic 2010 - Multiline Function Lambdas

  A multiline Function lambda is a lambda expression that represents a Function containing one or more statements.  The “Function” keyword can be used to create a multiline lambda that returns a value.  The following examples how to create mutiline Function lambdas.  The first creates a multiline Function lambda and assigns it to a variable.  The second uses a multiline Function lamda inline.           ' A multiline Function lambda created and assigned to a variable.         ' Note: Does not require line continuation characters.         Dim x = Function(n As Integer)                     If n Mod 2 = 0 Then                         Return 3                     Else                         Return 3.14                     End If                 End Function         ' Use the lamda and display it's result.         MsgBox(x(33).ToString & " is the answer.")           ' A multiline Function lambda created and used inline.         Dim theAnswer = Function(n As Integer)                             If n Mod 2 = 0 Then                                 Return 3                             Else                                 Return 3.14                             End If                         End Function         ' Use the lamda and display it's result.         MsgBox(x(14).ToString & " is the answer.") Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 06 2009, 01:07 PM by Mike McIntyre Filed under: Multiline, lambda, function

• Visual Basic 2010 - Multiline Sub Lambdas

  A multiline Sub lambda is a lambda expression that represents a Sub containing one or more statements.  Visual Basic 9.0 only supported lambdas that were a single expression that returned a value; for example, the following line was an error:       'Error - Console.WriteLine doesn't return a value     Array.ForEach(nums, Function(n) Console.WriteLine(n))   With Visual Basic 10.0, lambdas can now contain expressions that do not return a value:      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click         ' Delcare an array of integers named number filled with four numbers.         Dim numbers() = {1, 6, 9, 4}         ' Use a multiline Sub lambda to iterate the array elements and print them to the Results window.         Array.ForEach(numbers, Sub(n)                                    Console.Write("Number: ")                                    Console.WriteLine(n)                                End Sub)     End Sub   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 05 2009, 12:52 PM by Mike McIntyre Filed under: visual basic 10, lambda, sub lambda

• VB 20010 - Continuing a Statement over Multiple Lines after a Comma

  Visual Basic 2010 provides mechanisms to continue lines of a statment without the traditional _ (underline) character. One mechanism is to contiue the statement on a new line after a comma. Here's and example:     Private Function ProcessOrder(ByVal customer As Person,                                   ByVal orderDate As DateTime,                                   ByVal ship As Boolean) As ProcessResult         Dim processResults As New ProcessResult         '  Processing code omitted for brevity.         Return processResults     End Function   Mike McIntyre's .Net Journal getdotnetcode.com Posted Oct 04 2009, 11:35 AM by Mike McIntyre Filed under: line continuation