vba 检查访问表单字段是否为空，如果不为空则调用添加功能
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Check Access Form Field for Null, if Not Null then Call the Add Feature
提问by T-Rex
I have this simple Access Form that when you fill out the form and forget to fill out the Business Unit field, a msgBox will pop up telling you so and setFocus to that very Combo box. If it is Not null, I want to call the next feature. The first part of this code works, but the when it is notNull it wil not carry on.
我有一个简单的访问表单，当您填写表单并忘记填写业务单位字段时，会弹出一个 msgBox 告诉您，并将焦点设置到那个组合框。如果它不为空，我想调用下一个功能。这段代码的第一部分有效，但当它不为空时它不会继续。
Private Sub Image_AddNon_RPS_Button_Click()
If IsNull(Me.BU_Selected_Add) Then
MsgBox "Please Select a Business Unit!", vbOKOnly
Exit Sub
End If
Me.Combo_BU_Selector.SetFocus
Exit Sub
If Not IsNull(Me.BU_Selected_Add) Then
Call Add_RPS_LINE
End If
End Sub
Does anybody see where I am totally out in left field?
有没有人看到我在左场完全出局？
回答by Ken White
You've got an extra Exit Sub(the one after the first MsgBox) that stops your code from doing what you want. Also, your first End Ifis in the wrong location.
你有一个额外的Exit Sub（第一个之后的MsgBox）阻止你的代码做你想做的事。此外，您的第一个End If位置错误。
Try something like this instead:
试试这样的：
Private Sub Image_AddNon_RPS_Button_Click()
If IsNull(Me.BU_Selected_Add) Then ' No business unit
MsgBox "Please Select a Business Unit!", vbOKOnly ' Tell user
Me.Combo_BU_Selector.SetFocus ' Focus the control
Exit Sub ' Exit the method
End If ' End the IsNull test
Call Add_RPS_LINE ' You only get here if the above doesn't execute
End Sub
It helps if you learn to properly indent your code to match Ifand End Ifvisually, so you can see where they line up (match) and where they don't. :-)
如果您学会正确缩进代码以匹配If和End If视觉化，这会有所帮助，这样您就可以看到它们排列（匹配）的位置以及它们不排列的位置。:-)
回答by unDeadHerbs
If you correct the indentation of your code to:
如果您将代码的缩进更正为：
Private Sub Image_AddNon_RPS_Button_Click()
If IsNull(Me.BU_Selected_Add) Then
MsgBox "Please Select a Business Unit!", vbOKOnly
Exit Sub
End If
Me.Combo_BU_Selector.SetFocus
Exit Sub
If Not IsNull(Me.BU_Selected_Add) Then
Call Add_RPS_LINE
End If
End Sub
You can clearly see that the Exit Subin the middle will terminate the function before it gets to Call Add_RPS_LINE.
您可以清楚地看到Exit Sub中间的 将在到达 之前终止函数Call Add_RPS_LINE。
If you look at the two Ifstatements you have, you can see that they are almost the same and so an Elseis in order, resulting in this simpler and more readable code.
如果您查看If您拥有的两个语句，您会发现它们几乎相同，因此Else顺序一致，从而产生了更简单、更易读的代码。
Private Sub Image_AddNon_RPS_Button_Click()
If IsNull(Me.BU_Selected_Add) Then
MsgBox "Please Select a Business Unit!", vbOKOnly
Me.Combo_BU_Selector.SetFocus
Else
Call Add_RPS_LINE
End If
End Sub
