cannot hide process

i want to start calc.exe and hide it

but only can start the exex but cant hide

what error in my code??

Imports System.Runtime.InteropServices
Imports System.IntPtr
Public Class Form1
    <DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _  
    Private Shared Function ShowWindowAsync(ByVal hwnd As IntPtr, ByVal nCmdShow As Integer) As B开发者_运维知识库oolean
    End Function 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim a As IntPtr = Process.GetProcessesByName("Calc")(0).Id
        ShowWindowAsync(a, 0)
    End Sub
End Class

The following code should do what you want using managed code, but when I tried it using calc it would not start hidden or minimized (other exe's worked as expected so it may be something peculiar with calc?)

    Dim procStartInfo As New ProcessStartInfo
    Dim procExecuting As New Process

    With procStartInfo
        .FileName = "calc"
        .WindowStyle = ProcessWindowStyle.Hidden
    End With

    procExecuting = Process.Start(procStartInfo)

I did time ago a snippet which works with any proccess, are two generic functions and also has recursive mode and is easy to use:

#Region " Hide-Restore Process "

    ' [ Hide-Restore Process Function ]
    '
    ' // By Elektro H@cker
    '
    ' Examples :
    '
    ' Hide_Process(Process.GetCurrentProcess().MainModule.ModuleName, False)
    ' Hide_Process("notepad.exe", False)
    ' Hide_Process("notepad", True)
    '
    ' Restore_Process(Process.GetCurrentProcess().MainModule.ModuleName, False)
    ' Restore_Process("notepad.exe", False)
    ' Restore_Process("notepad", True)

    Dim Process_Handle_Dictionary As New Dictionary(Of String, IntPtr)

    <System.Runtime.InteropServices.DllImport("User32")> Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Int32) As Int32
    End Function

    Private Sub Hide_Process(ByVal Process_Name As String, Optional ByVal Recursive As Boolean = False)

        If Process_Name.ToLower.EndsWith(".exe") Then Process_Name = Process_Name.Substring(0, Process_Name.Length - 4)

        Dim proc() As Process = Process.GetProcessesByName(Process_Name)

        If Recursive Then
            For proc_num As Integer = 0 To proc.Length - 1
                Try
                    Process_Handle_Dictionary.Add(Process_Name & ";" & proc(proc_num).Handle.ToString, proc(proc_num).MainWindowHandle)
                    ShowWindow(proc(proc_num).MainWindowHandle, 0)
                Catch ex As Exception
                    ' MsgBox(ex.Message) ' The handle already exist in the Dictionary
                End Try
                Application.DoEvents()
            Next
        Else
            If Not proc.Length = 0 AndAlso Not proc(0).MainWindowHandle = 0 Then
                Process_Handle_Dictionary.Add(Process_Name & ";" & proc(0).Handle.ToString, proc(0).MainWindowHandle)
                ShowWindow(proc(0).MainWindowHandle, 0)
            End If
        End If

    End Sub

    Private Sub Restore_Process(ByVal Process_Name As String, Optional ByVal Recursive As Boolean = False)

        If Process_Name.ToLower.EndsWith(".exe") Then Process_Name = Process_Name.Substring(0, Process_Name.Length - 4)

        Dim Temp_Dictionary As New Dictionary(Of String, IntPtr) ' Replic of the "Process_Handle_Dictionary" dictionary
        For Each Process In Process_Handle_Dictionary : Temp_Dictionary.Add(Process.Key, Process.Value) : Next

        If Recursive Then
            For Each Process In Temp_Dictionary
                If Process.Key.ToLower.Contains(Process_Name.ToLower) Then
                    ShowWindow(Process.Value, 9)
                    Process_Handle_Dictionary.Remove(Process.Key)
                End If
                Application.DoEvents()
            Next
        Else
            For Each Process In Temp_Dictionary
                If Process.Key.ToLower.Contains(Process_Name.ToLower) Then
                    ShowWindow(Process.Value, 9)
                    Process_Handle_Dictionary.Remove(Process.Key)
                    Exit For
                End If
                Application.DoEvents()
            Next
        End If

    End Sub

#End Region