Microsoft KB Archive/276346

= FIX: SendKeys Function Locks Keyboard on Windows 2000 =

Article ID: 276346

Article Last Modified on 9/12/2006

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APPLIES TO


 * Microsoft Visual Basic 5.0 Professional Edition, when used with:
 * Microsoft Windows 2000 Service Pack 1
 * Microsoft Visual Basic 6.0 Professional Edition, when used with:
 * Microsoft Windows 2000 Service Pack 1
 * Microsoft Visual Basic 5.0 Enterprise Edition, when used with:
 * Microsoft Windows 2000 Service Pack 1
 * Microsoft Visual Basic 6.0 Enterprise Edition, when used with:
 * Microsoft Windows 2000 Service Pack 1

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This article was previously published under Q276346



SYMPTOMS
When a Visual Basic program is running, the keyboard on your Windows 2000-based computer freezes.

This problem can also occur if the application is hosted on a Terminal Server, and if the client is running Windows 2000. The following system event is logged on the Windows 2000-based computer:

Event Type:Error

Event Source:i8042prt

Event Category:None

Event ID:27

Description:

The operation on timed out (time out is configurable via the registry).



CAUSE
This problem is the result of a bug in the Windows 2000 keyboard driver, and only occurs in conjunction with the Visual Basic SendKeys function.



RESOLUTION
To resolve this problem on a Windows 2000-based computer that is not running Terminal Services, install Windows 2000 Service Pack 2 (SP2) from the following Microsoft Web site:

http://www.microsoft.com/windows2000/downloads/servicepacks/sp2/default.mspx

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows 2000 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:   Date         Time     Version         Size     File name ---  05/18/2000   07:17p   5.0.2195.2096   48,592   I8042prt.sys

To unlock the keyboard manually, on the Start menu, point to Settings, and then click Control Panel. Click Keyboard, and then reset the Keyboard Refresh Rate.



WORKAROUND
There are also two programmatic workarounds to this problem:

Workaround 1
Replace the SendKeys function with the keybd_event API function as follows: Private Declare Sub keybd_event Lib &quot;user32&quot; (ByVal bVk As Byte,ByVal _ bScan As Byte, ByVal dwFlags As Long, ByVal dwExtraInfo As Long)

Const KEYEVENTF_KEYUP = &H2 Const VK_TAB = &H9

keybd_event VK_TAB, 0, 0, 0 keybd_event VK_TAB, 0, KEYEVENTF_KEYUP, 0

Workaround 2
Replace the Sendkeys function with the PostMessage API function as follows: Private Declare Function PostMessage Lib &quot;user32&quot; Alias &quot;PostMessageA&quot; _ (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _  ByVal lParam As Long) As Long

Const WM_KEYDOWN As Long = &H100 Const VK_TAB As Long = &H9 Dim retVal as long

retVal = PostMessage(Me.hwnd, WM_KEYDOWN, VK_TAB, 0)



STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.



Steps to Reproduce Behavior
 On a computer that is running Windows 2000, create a new Standard EXE project in Visual Basic. Form1 is created by default. Set the Keypreview property of Form1 to True. Add six TextBoxes to Form1.  Add the following code to the General Declarations section of Form1: Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer) If KeyCode = 13 Then SendKeys &quot;{tab}&quot; End If End Sub </li> Run the project.</li> Press and hold down the Enter key on the numeric keypad, and note that the keyboard locks in approximately five seconds.</li></ol>

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

262798 PS/2 Keyboard/Mouse Not Recognized When Plugged Into Running Computer

Additional query words: stops responding key pad board

Keywords: kbbug kbqfe kbprb kbpending kbhotfixserver KB276346

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