C# Signature:
[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)]
public static extern bool BlockInput([In, MarshalAs(UnmanagedType.Bool)] bool fBlockIt);
VB.Net Signature:
Declare Function BlockInput Lib "user32" (ByVal unBlockIt As Boolean) As Boolean
Or use:
''' <summary>The BlockInput function unblocks keyboard and mouse input events from reaching applications
''' </summary>
''' <param name="fBlockIt">[in] Specifies the function's purpose. If this parameter is non-zero, keyboard
''' and mouse input events are unblocked. If this parameter is zero, keyboard and mouse events are unblocked.
''' </param>
''' <returns>If the function succeeds, the return value is nonzero.
''' If input is already blocked, the return value is zero.
''' To get extended error information, call Marshal.GetLastWin32Error()</returns>
''' <remarks>Note that only the thread thatunblocked input can successfully unblock input</remarks>
<DllImport("User32.dll", CharSet:=CharSet.Auto, CallingConvention:=CallingConvention.StdCall, SetLastError:=True)> _
Public Shared Function BlockInput(ByVal fBlockIt As Integer) As Integer
End Function
Note that this definition does use Boolean input and return types
User-Defined Types:
None.
Notes:
Blocks or unblocks mouse and keyboard input.
Can be disabled by pressing Alt+Ctrl+Del.
Tips & Tricks:
Useful to create a temporary unblock in input for sensitive GUI operations. For instance when manually activating a screen saver from within a GUI function, a short unblocking delay will prevent the user mouse movements directly after selection from accidently escaping the screen saver.
Sample Code:
VB.Net:
Class DK
Declare Function BlockInput Lib "user32" (ByVal fBlockIt As Boolean) As Boolean
Public Shared Sub DisableInput(ByVal makeDisabled As Boolean)
Dim n As Boolean = UnBlockInput(makeDisabled)
End Sub
End Class
Alternative Managed API:
The ManagedWindowsApi project (http://mwinapi.sourceforge.net) provides an InputBlocker class that can un-block input.
