VB.NET change background color or image in windows form application in the taskbar when user running multiple instances of application

Question

Thanks for reading. We have a VB.NET windows form application running .NET 4.8 Framework. Users often run multiple instances of the application. When this occurs, all of the same colored minimized windows in the taskbar make it difficult for the user to distinguish the different instances. I would like to implement a background color change based on the users Process ID (System.Diagnostics.Process.GetCurrentProcess). For instance, if the user had 3 instances of the application running with 2 forms open apiece then there would be 6 windows in the taskbar of the same color and/or text. I would like to differentiate between those 3 instances if possible. Thanks for the help.

Answer 1

change background color or image in windows form application in the taskbar...

You can use ITaskbarList3.SetOverlayIcon to set a colored icon in the Taskbar Button, like in the MS SDK sample :

Answer 2

Basic logic would go into MyApplication class which is created from project properties, Application tab, View Application events button.

Something like this which as coded is limited to colors/open instances of an application.

Imports Microsoft.VisualBasic.ApplicationServices  
  
Namespace My  
    Partial Friend Class MyApplication  
        Public backColorDictionary As Dictionary(Of Integer, Color) =  
                   New Dictionary(Of Integer, Color) From  
            {  
                {1, Color.Red},  
                {2, Color.Green},  
                {3, Color.Blue},  
                {4, Color.DarkOrange}  
            }  
  
        Private _color As Color  
        ''' <summary>  
        ''' Form background color  
        ''' </summary>  
        ''' <returns></returns>  
        Public ReadOnly Property BackColor() As Color  
            Get  
                Return _color  
            End Get  
        End Property  
  
        ''' <summary>  
        ''' Logic to determine background color to use or a default if more instance  
        ''' of the application open than colors in <see cref="backColorDictionary"/>  
        ''' </summary>  
        ''' <param name="sender"></param>  
        ''' <param name="e"></param>  
        Private Sub MyApplication_Startup(sender As Object, e As StartupEventArgs) Handles Me.Startup  
  
            Dim currentProcess = Process.GetCurrentProcess().ProcessName  
            Dim counter = Process.GetProcessesByName(currentProcess).Length  
            If counter <= backColorDictionary.Count Then  
                _color = backColorDictionary(counter)               '  
            Else  
                _color = Color.White  
            End If  
  
        End Sub  
    End Class  
End Namespace  
  

Then in a form load event

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load  
  
    BackColor = My.Application.BackColor  

Update

Here we get over 100 colors

Imports System.Reflection  
Imports Microsoft.VisualBasic.ApplicationServices  
  
Namespace My  
    Partial Friend Class MyApplication  
        Public backColorDictionary As Dictionary(Of Integer, Color) = CreateColorsDictionary()  
  
        Public Shared Function ColorStructToList() As List(Of Color)  
            Return GetType(Color).GetProperties(  
                BindingFlags.Static Or  
                BindingFlags.DeclaredOnly Or  
                BindingFlags.Public).Select(  
                    Function(c)  
                        Return CType(c.GetValue(Nothing, Nothing), Color)  
                    End Function).ToList()  
        End Function  
        Private Function CreateColorsDictionary() As Dictionary(Of Integer, Color)  
            Dim colors = ColorStructToList()  
  
            Dim results = colors.Select(Function(item, index) New With  
                                           {  
                                                .Index = index + 1,  
                                                .Color = item  
                                           })  
            Dim Dictionary = New Dictionary(Of Integer, Color)  
  
  
            For Each anonymous In results  
  
                If anonymous.Color = Color.Transparent Then  
                    Dictionary.Add(anonymous.Index, Color.White)  
                Else  
                    Dictionary.Add(anonymous.Index, anonymous.Color)  
                End If  
  
            Next  
  
            Return Dictionary  
  
        End Function  
  
        Private _color As Color  
        ''' <summary>  
        ''' Form background color  
        ''' </summary>  
        ''' <returns></returns>  
        Public ReadOnly Property BackColor() As Color  
            Get  
                Return _color  
            End Get  
        End Property  
  
        ''' <summary>  
        ''' Logic to determine background color to use or a default if more instance  
        ''' of the application open than colors in <see cref="backColorDictionary"/>  
        ''' </summary>  
        ''' <param name="sender"></param>  
        ''' <param name="e"></param>  
        Private Sub MyApplication_Startup(sender As Object, e As StartupEventArgs) Handles Me.Startup  
  
            Dim currentProcess = Process.GetCurrentProcess().ProcessName  
            Dim counter = Process.GetProcessesByName(currentProcess).Length  
            If counter <= backColorDictionary.Count Then  
                _color = backColorDictionary(counter)               '  
            Else  
                _color = Color.White  
            End If  
  
        End Sub  
    End Class  
End Namespace  
  

Opening three instances gets

Answer 3

very helpful both Castorix31 and Karen. Thanks!