WaitForInputIdle

Waits until the specified process is in an idle state. Idle is defined as the state where the process is ready to process a message but no message is pending.

Code:

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    Const INFINITE As Int32 = -1
    Const WAIT_TIMEOUT As Int32 = 258
    Private Declare Function apiWaitForInputIdle Lib "user32" Alias "WaitForInputIdle" (ByVal hProcess As Int32, ByVal dwMilliseconds As Int32) As Int32
    Public Function WindowWaitForIdle(ByVal hWnd As Int32, Optional ByVal dwMilliseconds As Int32 = 5000) As Boolean
        Try ''''''''''''''''''''''''''''''''''''''''''''In case handle is invalid
            For Each p As Process In Process.GetProcesses() 'Iterate through all processes
                If p.MainWindowHandle.ToInt32 = hWnd Then 'If the handle matches the specified handle
                    'p.WaitForInputIdle(dwMilliseconds)'You could do this, but it may not always wait long enough like the API does
                    WindowWaitForIdle = CBool(apiWaitForInputIdle(p.Handle.ToInt32, dwMilliseconds)) 'Set return value
                End If
            Next
        Catch ex As Exception
        End Try ''''''''''''''''''''''''''''''''''''''''Ignore any error due to handles with no graphical interface
        Return Not WindowWaitForIdle '''''''''''''''''''Return the inverse of API call, which is zero for success instead
    End Function

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.Text = WindowWaitForIdle(Me.Handle.ToInt32, 5000).ToString
    End Sub

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