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Single Instanced WPF applications issue

Unanswered Single Instanced WPF applications issue

  • Monday, January 30, 2012 4:41 PM
     
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    Afternoon all,

    I've recently gone through the steps in this article to create a single instanced wpf application http://blogs.microsoft.co.il/blogs/arik/archive/2010/05/28/wpf-single-instance-application.aspx . After I tested and closed the first test of this I'm now constantly getting

    Class 'Application' must implement 'Sub InitializeComponent()' for interface 'System.Windows.Markup.IComponentConnector'.

    some times clicking rebuild will resolve the issue and I can run the code other times it just continues to fail. Has anyone else come across this and if so any ideas on what im doing wrong ?

    contents of my Application.xaml.vb

     

    Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Windows
Imports System.Windows.Markup


''' <summary>
''' Interaction logic for App.xaml
''' </summary>
Partial Public Class App
    Inherits Application
    Implements ISingleInstanceApp, IComponentConnector
    Private Const Unique As String = "My_Unique_Application_String"
    Private _contentLoaded As Boolean

    <STAThread()> _
    Public Shared Sub Main()
        If SingleInstance(Of App).InitializeAsFirstInstance(Unique) Then
            Dim a = New App()

            a.InitializeComponent()
            a.Run()

            ' Allow single instance code to perform cleanup operations
            SingleInstance(Of App).Cleanup()
        End If
    End Sub

#Region "ISingleInstanceApp Members"
    Public Function ISingleInstanceApp_SignalExternalCommandLineArgs(ByVal args As IList(Of String)) As Boolean Implements ISingleInstanceApp.SignalExternalCommandLineArgs
        Dim win As MainWindow = My.Application.MainWindow
        win.newCommandLineArgs(args)

        Return True
    End Function

#End Region
End Class

     


    and the application.xaml is pretty empty with

     

    <Application x:Class="Application"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    StartupUri="MainWindow.xaml"
ShutdownMode="OnMainWindowClose">
    <Application.Resources>
        
    </Application.Resources>
</Application>


    any help is appreciated

     

    *EDIT*

    I forgot to mention the files that are throwing the error are Application.g.vb and Application.g.i.vb

    the contents of those files are

    #ExternalChecksum("..\..\..\Application.xaml","{406ea660-64cf-4c82-b6f0-42d48172a799}","F5BE6FD6DCB7C43A14B51A47D8190D35")
'------------------------------------------------------------------------------
' <auto-generated>
'     This code was generated by a tool.
'     Runtime Version:4.0.30319.239
'
'     Changes to this file may cause incorrect behavior and will be lost if
'     the code is regenerated.
' </auto-generated>
'------------------------------------------------------------------------------

Option Strict Off
Option Explicit On

Imports System
Imports System.Diagnostics
Imports System.Windows
Imports System.Windows.Automation
Imports System.Windows.Controls
Imports System.Windows.Controls.Primitives
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Forms.Integration
Imports System.Windows.Ink
Imports System.Windows.Input
Imports System.Windows.Markup
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports System.Windows.Media.Effects
Imports System.Windows.Media.Imaging
Imports System.Windows.Media.Media3D
Imports System.Windows.Media.TextFormatting
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports System.Windows.Shell


'''<summary>
'''Application
'''</summary>
<Microsoft.VisualBasic.CompilerServices.DesignerGenerated(), _
 System.CodeDom.Compiler.GeneratedCodeAttribute("PresentationBuildTasks", "4.0.0.0")> _
Partial Public Class Application
    Inherits System.Windows.Application
    Implements System.Windows.Markup.IComponentConnector

    Private _contentLoaded As Boolean

    '''<summary>
    '''InitializeComponent
    '''</summary>
    <System.Diagnostics.DebuggerNonUserCodeAttribute()> _
    Public Sub InitializeComponent()

        #ExternalSource("..\..\..\Application.xaml",2)
        Me.StartupUri = New System.Uri("MainWindow.xaml", System.UriKind.Relative)
        
        #End ExternalSource
        If _contentLoaded Then
            Return
        End If
        _contentLoaded = true
        Dim resourceLocater As System.Uri = New System.Uri("/LogReader;component/application.xaml", System.UriKind.Relative)
        
        #ExternalSource("..\..\..\Application.xaml",1)
        System.Windows.Application.LoadComponent(Me, resourceLocater)
        
        #End ExternalSource
    End Sub
    
    <System.Diagnostics.DebuggerNonUserCodeAttribute(),  _
     System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes"),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity"),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily")>  _
    Sub System_Windows_Markup_IComponentConnector_Connect(ByVal connectionId As Integer, ByVal target As Object) Implements System.Windows.Markup.IComponentConnector.Connect
        Me._contentLoaded = true
    End Sub
End Class

    and

    #ExternalChecksum("..\..\..\Application.xaml","{406ea660-64cf-4c82-b6f0-42d48172a799}","B23A0EBE5EE6C637AB236986A35F74DB")
'------------------------------------------------------------------------------
' <auto-generated>
'     This code was generated by a tool.
'     Runtime Version:4.0.30319.239
'
'     Changes to this file may cause incorrect behavior and will be lost if
'     the code is regenerated.
' </auto-generated>
'------------------------------------------------------------------------------

Option Strict Off
Option Explicit On

Imports System
Imports System.Diagnostics
Imports System.Windows
Imports System.Windows.Automation
Imports System.Windows.Controls
Imports System.Windows.Controls.Primitives
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Forms.Integration
Imports System.Windows.Ink
Imports System.Windows.Input
Imports System.Windows.Markup
Imports System.Windows.Media
Imports System.Windows.Media.Animation
Imports System.Windows.Media.Effects
Imports System.Windows.Media.Imaging
Imports System.Windows.Media.Media3D
Imports System.Windows.Media.TextFormatting
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports System.Windows.Shell


'''<summary>
'''Application
'''</summary>
<Microsoft.VisualBasic.CompilerServices.DesignerGenerated(),  _
 System.CodeDom.Compiler.GeneratedCodeAttribute("PresentationBuildTasks", "4.0.0.0")>  _
Partial Public Class Application
    Inherits System.Windows.Application
    Implements System.Windows.Markup.IComponentConnector
    
    Private _contentLoaded As Boolean
    
    '''<summary>
    '''InitializeComponent
    '''</summary>
    <System.Diagnostics.DebuggerNonUserCodeAttribute()>  _
    Public Sub InitializeComponent()
        
        #ExternalSource("..\..\..\Application.xaml",4)
        Me.StartupUri = New System.Uri("MainWindow.xaml", System.UriKind.Relative)
        
        #End ExternalSource
        If _contentLoaded Then
            Return
        End If
        _contentLoaded = true
        Dim resourceLocater As System.Uri = New System.Uri("/LogReader;component/application.xaml", System.UriKind.Relative)
        
        #ExternalSource("..\..\..\Application.xaml",1)
        System.Windows.Application.LoadComponent(Me, resourceLocater)
        
        #End ExternalSource
    End Sub
    
    <System.Diagnostics.DebuggerNonUserCodeAttribute(),  _
     System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Design", "CA1033:InterfaceMethodsShouldBeCallableByChildTypes"),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Maintainability", "CA1502:AvoidExcessiveComplexity"),  _
     System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily")>  _
    Sub System_Windows_Markup_IComponentConnector_Connect(ByVal connectionId As Integer, ByVal target As Object) Implements System.Windows.Markup.IComponentConnector.Connect
        Me._contentLoaded = true
    End Sub
End Class


     

     


    • Edited by New_Coder Monday, January 30, 2012 5:17 PM
    •  
     

All Replies

  • Monday, January 30, 2012 6:06 PM
     
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    You can contact the developer of this code on discussion forum on codeproject 

    http://www.codeproject.com/Articles/84270/WPF-Single-Instance-Application

     

    Else you could check running process and use following code to check for single instance

    Private Sub CheckSingleInstance()
        Dim prc As Process = Process.GetCurrentProcess
        Dim processes() As Process = Process.GetProcessesByName(prc.ProcessName)
        If processes.Count > 1 Then
            MsgBox("Application is already running")
            'Application.Current.Shutdown()
        End If
    End Sub


    You can also use Mutex to check for single instance

    http://odetocode.com/blogs/scott/archive/2004/08/20/the-misunderstood-mutex.aspx

    Gaurav Khanna | Microsoft VB.NET MVP
     
  • Tuesday, January 31, 2012 10:08 AM
     
     
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    Thanks for the suggestions Khanna,

    although the code snippet wouldnt work for me as this wouldn't allow me to pass in subsequent command line args which is what I need, in regards to asking the original developer I have since posted the question to him.

     

    My question remains though, how do you resolve Class 'Application' must implement 'Sub InitializeComponent()' for interface 'System.Windows.Markup.IComponentConnector'. which are thrown in Application.g.vb and Application.g.i.vb ?

     
  • Tuesday, January 31, 2012 4:54 PM
     
     
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    I have managed to build the code again now and when ever it breaks (which is often) I can resolve.
    The temporary fix until I can work out why it is occuring is to change the designer generated code (Application.g.vb and Application.g.i.vb), the fix is to add "Implements IComponentConnector.InitializeComponent" next to the sub routine InitializeComponent() that is always present in these files.

    If anyone can assist in why these files are not automaticaly adding this, it would save my sanity :)

     
  • Tuesday, January 31, 2012 5:06 PM
     
     
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    InitializeComponent is a fundamental and required call in the code behind.  You have either renamed the namespace or class in the code behind or in the XAML without synching both.  DO NOT change code in the "g" code.  The "g" stands for generated and it will be overwritten.  I have found no problems in generated code in my three years of using WPF.  Chances are high it's either in the XAML or Code Behind for that view.
    JP Cowboy Coders Unite!
     
  • Tuesday, January 31, 2012 5:10 PM
     
     
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    For single instance applications you can use a static GetInstance method which returns the saved static instance of the control from the CTOR.  Not thread safe put pretty good solution and quick.
    JP Cowboy Coders Unite!
     
  • Saturday, March 31, 2012 4:25 PM
     
     
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    I have the same problem right now and I was just wondering if you ever managed to solve it? If so it would be a great solution to have in the public domain here.

    Thanks,

    Sam.

     
  • Saturday, March 31, 2012 9:59 PM
     
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    Afternoon all,

    I've recently gone through the steps in this article to create a single instanced wpf application http://blogs.microsoft.co.il/blogs/arik/archive/2010/05/28/wpf-single-instance-application.aspx . After I tested and closed the first test of this I'm now constantly getting

    Class 'Application' must implement 'Sub InitializeComponent()' for interface 'System.Windows.Markup.IComponentConnector'.

    some times clicking rebuild will resolve the issue and I can run the code other times it just continues to fail. Has anyone else come across this and if so any ideas on what im doing wrong ?

    contents of my Application.xaml.vb

     

    Imports System.Collections.Generic
Imports System.Configuration
Imports System.Data
Imports System.Linq
Imports System.Windows
Imports System.Windows.Markup


''' <summary>''' Interaction logic for App.xaml''' </summary>PartialPublicClass App
    Inherits Application
    Implements ISingleInstanceApp, IComponentConnector
    PrivateConst Unique AsString = "My_Unique_Application_String"Private _contentLoaded AsBoolean

    Hi

    afaics you shouldn't implement IComponentConnector in your own App.xaml.vb
    file (not the generated App.g.vb).
    IComponentConnector is "added" and explicitly implemented inside
    App.g.vb by the Code generator.
    So having a second Implements statement might cause this conflict
    and removing "Implements IComponentConnector" from your own code
    might solve the issue (not sure but worth a try)
    Also "_contentLoaded" is a generated field of the App.g.vb file, that should not be explicitly
    declared once again in your own code.
    Seems part of the generated file have merged into your own code.

    Chris