How to put focus to textbox as needed

问题

I have a textbox on a userform. If the user fails to enter anything in this textbox, I need to trap that to force an entry. I can do this easily enough, but after notifying the user tht they need to make an entry, I want the focus to return to the textbox. Right now, it doesn't do that. Here is my code:

Private Sub txtAnswer_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)

Select Case KeyCode
    Case 13:
        If Me.txtAnswer.Value = "" Then
            temp = MsgBox("You need to enter an answer!", vbCritical + vbOKOnly, "No Answer Found!")
            Me.txtAnswer.SetFocus
        Else
            recordAnswer
        End If
    End Select

End Sub

This code works fine in that the message box pops up if the textbox is left blank. After clearing the message box, if I hit enter immediately again, the message box reappears, suggesting that the focus is on the textbox. However, if I try to enter a character (like the number '1' for example) nothing appears in the textbox.

Can anybody suggest how I can get the focus back on this textbox in a way that will allow the user to enter data? Thank you!

回答1:

Why are you not using an 'ok' button to complete the action?

You should not bother users with messages while they are typing in a form. Do it at the end.

Private Sub OK_Click()

    '// Validate form
    If txtAnswer.Text = vbNullString Then
        MsgBox "You need to enter an answer!", vbExclamation, "No Answer Found!"
        txtAnswer.SetFocus
        Exit Sub
    End If

    '// You have reached here so form is correct carry on
    recordAnswer

End Sub

If you really want to use the behaviour you asked for then try this:

Private Sub txtAnswer_KeyDown(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)

    Select Case KeyCode
    Case 13:
        If Me.txtAnswer.Value = "" Then
            temp = MsgBox("You need to enter an answer!", vbCritical + vbOKOnly, "No Answer Found!")              
            KeyCode = 0
        Else
            recordAnswer
        End If
    End Select

End Sub

The problem is that in your code you are setting focus but the enter key is firing afterwards. You don't need to set focus because the textbox already has the focus you just need to cancel the enter key.

回答2:

The other answers seem really complicated. I had a similar problem and really wanted a text warning. It seemed easier for me to just make an invisible label on the form that would show up if the input was incorrect. I also made the background of the label red so that the user would notice something was wrong. Doing it this way kept the cursor visible and right where they left off.

Public Function amount(ByRef cont As MSForms.TextBox) As Integer
'makes sure that a number is used
'could change to account for decimals if necessary
Dim i As Long
On Error Resume Next
i = 0
If (cont.Value = "") Then Exit Function
    Do While i < 1000000
        If (cont.Value = i) Then
            UserForm1.Label257.Visible = False
            Exit Function
        End If
        i = i + 1
    Loop
UserForm1.Label257.Visible = True
amount = 1
End Function

Public Sub qty_BeforeUpdate(ByVal Cancel As MSForms.ReturnBoolean)
If amount(UserForm1.qty) = 1 Then
    Cancel = True
End If
End Sub

I hope this helps other who run into this problem later on.

回答3:

Looking at the above code, I assume the i counter is to keep it going? Sorry a bit rusty, been a few years since I've done code.

At any rate, if thats the case you could always run it while i=0, do (or while true).

Sorry, first time posting here, hope that made sense.

来源：https://stackoverflow.com/questions/10906714/how-to-put-focus-to-textbox-as-needed