PRB: SendKeys Does Not Work with NumLock or Caplock

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0
• Microsoft Visual Basic Standard Edition, 32-bit only, for Windows, version 4.0

SYMPTOMS

Using SendKeys to change the state of {CAPSLOCK} or {NUMLOCK} is not effective.

CAUSE

Toggling {CAPSLOCK} or {NUMLOCK} with the SendKeys statement is only in effect for the continuous subsequent keys sent by SendKeys. The state of {CAPSLOCK} or {NUMLOCK} is reset when Visual Basic yields to other processes. For example, this occurs when the SendKeys statement's Wait parameter is set to "True", or when a DoEvents statement is executed.

RESOLUTION

Use SendKeys to toggle {CAPSLOCK} or {NUMLOCK} only when sending a series of keys continuously in a single or multiple number of SendKeys statements. To toggle the {CAPSLOCK} or {NUMLOCK} permanently:

1. Use the KeyState control that comes with Visual Basic 4.0.
   
   - or -



2. Use the Win32 API. See the article in the References section for details.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Start a new Standard EXE project. From1 is created by default.



2. Add a TextBox to Form1 and paste the following code in the code Window:

   
       Private Sub Text1_Click()
           SendKeys "s"
           SendKeys "{CAPSLOCK}"  ' Turn on the CapsLock
           SendKeys "o"  ' will be printed in caps
           For i = 0 To 10
           SendKeys Chr(Asc("a") + i)  'will be printed in caps
           Next
           'DoEvents  ' uncommenting this will print next line in smalls
           SendKeys "o"  ' will be printed in caps
           SendKeys "{CAPSLOCK}"  ' Turn off the caps lock
           SendKeys "o"  ' Will be printed in smalls
       End Sub
    




3. Turn off the Caps Lock. Run the project. Note that the SendKeys work as expected.



4. Un-comment the DoEvents statement. Run the project. The Caps Lock is reset after the DoEvents call.



5. In any SendKeys statement after SendKeys "{CAPSLOCK}", pass "True" as the second parameter. The state of Caps Lock is reset after that statement.

REFERENCES

For additional information, please see the following article in the Microsoft Knowledge Base:

Q177674 : HOWTO: Toggle the NUM LOCK, CAPS LOCK, and SCROLL LOCK Keys

Keywords : kbcode kbnokeyword kbVBp400 kbVBp500 kbVBp600 kbGrpVB
Version : WINDOWS:4.0,5.0,6.0
Platform : WINDOWS
Issue type : kbprb