focus on this textbox on event of LostFocus

Question

Hi,

I want to focus on TextBox2 while user is keypressed [tab] in case of (not TextBox2.Text = 'A'),

But, TextBox3 is having its own checking while Not TextBox3.Text = "A", it will make focusing on TextBox3.

Finally, It will focus on TextBox3 instead of TextBox2. But, my goal is focus on TextBox2 in this case.

So, how to make focus on TextBox2 instead of TextBox3 with optimized coding, while keypressed [tab] on TextBox2 and stay on TextBox2 ?

Private Sub TextBox2_LostFocus(sender As Object, e As System.EventArgs) Handles TextBox2.LostFocus        
If Not TextBox2.Text = "A" Then            
TextBox2.Focus()        
End If    
End Sub    

Private Sub TextBox3_LostFocus(sender As Object, e As System.EventArgs) Handles TextBox3.LostFocus        
If Not TextBox3.Text = "A" Then            
TextBox3.Focus()        
End If   
End Sub

Answer 1

The LostFocus/GotFocus/Focus events/methods are low level (though ok to use). The documentation says the Enter and Leave events and the Select method should be used.

If I got you right, you want to keep the focus in Textbox2 if it does not contain an "A". Same for Textbox3. I suggest using the Validating event for this purpose.

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Armin

Answer 2

Hi Armin Zingler,

I am newbie on vb.net, please guide me how Validating event works and give me coding example in this case?

Thank you very much

Best Regards

Francis SZE

Answer 3

Hi Francis,

have a look at the sample in the documentation:

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating.aspx

---

Armin

Answer 4

I suggest using the Validating event for this purpose.

---

Armin

I agree with Armin.

The validating event fires whenever the user leaves the control (ergo, they've entered it and now go to move to another control), but unlike the ".Leaving" event, the event args allow you to "lock" your user in by setting e.Cancel = True.

If it's text, you might consider giving them an "out" by showing an ErrorProvider (it's in your toolbox, just grab it and drag to your form) then show them they need to correct the error -OR- clear the contents entirely in order to proceed. If it's a databound item though, this may not be wise, but it's something to consider.

---

Please call me Frank :)

Answer 5

Please follow this question, if interested

http://social.msdn.microsoft.com/Forums/en-US/vbgeneral/thread/2fbaaf57-f82e-490e-a240-0f050db3abf1