How can I read cursor position on a second screen?

Question

I need to monitor the Cursor.Position.X as it moves from the left side of my screen #1 (the primary screen) to the right side of screen #2, which is set up as an extension of the primary screen and to the right of it. They are both HD so my total viewing area is 3840 x 1050, and I need to continuously monitor the value of 'x' as it changes from zero to 3840.

In Visual Basic: Dim MposX as integer = Cursor.Position.X only works for the primary screen. How can I get it to continuously provide the X value numbers (1921 to 3840) when the cursor is on screen #2?

Answer 1

Maybe you can test with a Mouse Hook.

From doc :

pt
Type: POINT
The x- and y-coordinates of the cursor, in per-monitor-aware screen coordinates.

So you can check if there is a difference with or without a Manifest (PROCESS_DPI_AWARENESS enumeration)
by changing the <dpiAware> value

Test of a Mouse Hook =>

Imports System.Runtime.InteropServices  
  
Public Class Form1  
    Public Const WH_MIN As Integer = (-1)  
    Public Const WH_MSGFILTER As Integer = (-1)  
    Public Const WH_JOURNALRECORD As Integer = 0  
    Public Const WH_JOURNALPLAYBACK As Integer = 1  
    Public Const WH_KEYBOARD As Integer = 2  
    Public Const WH_GETMESSAGE As Integer = 3  
    Public Const WH_CALLWNDPROC As Integer = 4  
    Public Const WH_CBT As Integer = 5  
    Public Const WH_SYSMSGFILTER As Integer = 6  
    Public Const WH_MOUSE As Integer = 7  
    Public Const WH_HARDWARE As Integer = 8  
    Public Const WH_DEBUG As Integer = 9  
    Public Const WH_SHELL As Integer = 10  
    Public Const WH_FOREGROUNDIDLE As Integer = 11  
    Public Const WH_CALLWNDPROCRET As Integer = 12  
    Public Const WH_KEYBOARD_LL As Integer = 13  
    Public Const WH_MOUSE_LL As Integer = 14  
    Public Const WH_MAX As Integer = 14  
    Public Const WH_MINHOOK As Integer = WH_MIN  
    Public Const WH_MAXHOOK As Integer = WH_MAX  
  
    <StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Unicode)>  
    Public Structure MSLLHOOKSTRUCT  
        Public pt As System.Drawing.Point  
        Public mouseData As Integer  
        Public flags As Integer  
        Public time As Integer  
        Public dwExtraInfo As UInteger  
    End Structure  
  
    Public Delegate Function HookProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer  
  
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>  
    Public Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal lpfn As HookProc, ByVal hInstance As IntPtr, ByVal threadId As Integer) As Integer  
    End Function  
  
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>  
    Public Shared Function UnhookWindowsHookEx(ByVal idHook As Integer) As Boolean  
    End Function  
  
    <DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall)>  
    Public Shared Function CallNextHookEx(ByVal idHook As Integer, ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer  
    End Function  
  
    Shared hHook As Integer = 0  
    Private MouseLLProcedure As HookProc  
  
    Public Sub New()  
        InitializeComponent()  
    End Sub  
  
    Private Shared Label1 As Label = New Label()  
  
    Public Shared Function MouseLLProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer  
        If (nCode >= 0) Then  
            Dim pMSLLHOOKSTRUCT As MSLLHOOKSTRUCT = New MSLLHOOKSTRUCT()  
            pMSLLHOOKSTRUCT = CType(Marshal.PtrToStructure(lParam, pMSLLHOOKSTRUCT.[GetType]()), MSLLHOOKSTRUCT)  
            Label1.Text = pMSLLHOOKSTRUCT.pt.ToString()  
        End If  
  
        Return If(nCode < 0, CallNextHookEx(hHook, nCode, wParam, lParam), 0)  
    End Function  
  
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load  
        Label1.Size = New Size(100, 32)  
        Label1.Location = New Point(150, 150)  
        Label1.BorderStyle = BorderStyle.Fixed3D  
        Label1.BackColor = Color.Black  
        Label1.ForeColor = Color.Yellow  
        Label1.Font = New Font("Arial", 8.0F, FontStyle.Bold, GraphicsUnit.Point)  
        Label1.TextAlign = ContentAlignment.MiddleCenter  
        Me.Controls.Add(Label1)  
        Me.ClientSize = New System.Drawing.Size(400, 400)  
        MouseLLProcedure = New HookProc(AddressOf MouseLLProc)  
        hHook = SetWindowsHookEx(WH_MOUSE_LL, MouseLLProcedure, CType(0, IntPtr), 0)  
        CenterToScreen()  
    End Sub  
  
    Private Sub Form1_FormClosing(ByVal sender As Object, ByVal e As FormClosingEventArgs) Handles MyBase.FormClosing  
        If hHook <> 0 Then UnhookWindowsHookEx(hHook)  
    End Sub  
  
End Class  
  

Answer 2

Use the Win32 API GetCursorPos. I'm not aware of a .NET equivalent so you may need to PInvoke it.