将焦点设置回文本框

在用户移动到用户表单上的下一个字段之前，我需要检查文本框是否为空/空或空白。这是检查文本框是否为空/null/空白的代码。我的问题是它不会将焦点返回到文本框，而是移动到用户表单中的下一个字段。

Private Sub txtTDYLocation_lostfocus()
Dim Pcase As String
    'converts text to proper case
    
    If Trim(txtTDYLocation.Value & "") = "" Then
        MsgBox "Please enter TDY location", vbOKOnly
        txtTDYLocation.SetFocus
    Else
        Pcase = Me.txtTDYLocation
        Pcase = StrConv(Pcase, vbProperCase)
        Me.txtTDYLocation.Text = Pcase
        Me.txtTDYLocation = StrConv(Me.txtTDYLocation, 3)
   End If
End Sub

为此，您应该使用该事件txtTDYLocation_BeforeUpdate如果值为Null在文本框中。一旦取消设置为True焦点将无法离开文本框。

Private Sub txtTDYLocation_BeforeUpdate(Cancel As Integer)
    If Trim(txtTDYLocation & "") = "" Then
        MsgBox "Please enter TDY location", vbOKOnly
        Cancel = True
    End If
End Sub

And in txtTDYLocation_AfterUpdate()您可以更改该值。

Private Sub txtTDYLocation_AfterUpdate()
    Dim Pcase As String
    'converts text to proper case
    If Trim(txtTDYLocation.Value & "") <> "" Then
        Pcase = Me.txtTDYLocation
        Pcase = StrConv(Pcase, vbProperCase)
        Me.txtTDYLocation.Value = Pcase
        Me.txtTDYLocation = StrConv(Me.txtTDYLocation, 3)
   End If
End Sub