VBA MSFORMS 与控件 - 有什么区别

Question

向用户窗体添加控件时，以下有什么区别。我很困惑何时适合使用其中任何一种。

Dim aButton1 as MSFORMS.CommandButton
Dim aButton2 as Control.CommandButton
Dim aButton3 as CommandButton

Answer 1

先添加用户表单 .然后在 VBA IDE 按 F2 , 对象浏览器出现。在左上角是组合框，选择 MSForms .在类列表中，您可以看到属于 MSForms 对象库的类。

你可以看到命令按钮 和 控制在该列表中:



在你的代码中声明一个 CommandButton 类型的变量:

Dim button1 As MSForms.CommandButton
Dim button2 As CommandButton

变量 button1 肯定是 MSForms 中的 CommandButton 类型。 button2 可以是您在本地 VBA 项目中定义的自己的类 ...但如果您的本地 VBA 项目不包含任何具有此类名称的类，它也会从 MSForms 中考虑。然而 如果您引用另一个对象库 说'MSFoo'，它也将包含类CommandButton，你必须声明它们 完全合格 像这样:

Dim button1 As MSForms.CommandButton
Dim button2 As MSFoo.CommandButton

在你的代码中声明一个 Control 类型的变量:

Dim controlObject As MSForms.Control

使用 Control 类型的变量，就像控件的基类一样。例如。枚举控件集合:

For Each controlObject In Me.Controls
    Debug.Print VBA.TypeName(controlObject)
Next controlObject

或者作为函数中的参数，它不仅需要一种类型的控制:

Private Sub PrinControlName(ByRef c As MSForms.Control)
    Debug.Print c.Name
End Sub

因此，我认为使用像 MSForms.CommandButton 这样的完全限定名称通常是合适的。使用 Control.CommandButton 是错误的，除非您引用名为“Control”的对象库，其中包含类 CommandButton，否则不会编译。

编辑:

这里是 的例子本地创建的同名类 像 MSForm.CommandButton:


以及如何 类型名称 和 类型在这种情况下工作:

Option Explicit

Private m_buttonMsForms As MSForms.CommandButton
Private m_buttonLocal As CommandButton

Private Sub UserForm_Initialize()
    Set m_buttonMsForms = Me.Controls.Add( _
        "Forms.CommandButton.1", "testMsButton", True)
    Set m_buttonLocal = New CommandButton

    m_buttonLocal.Name = "testLocalButton"

    Debug.Print "We have two instances of two different button types: " & _
        m_buttonLocal.Name & " and " & m_buttonMsForms.Name

    ' Check instances with TypeName function
    ' TypeName function returns same results
    If VBA.TypeName(m_buttonMsForms) = VBA.TypeName(m_buttonLocal) Then
        Debug.Print "TypeName of both buton types returns same result"
    End If

    ' Check instances with TypeOf operator
    ' TypeOf doen't work with not initialised objects
    If m_buttonLocal Is Nothing Or m_buttonMsForms Is Nothing Then _
        Exit Sub

    ' TypeOf operator can distinguish between
    ' localy declared CommandButton type and MSForms CommandButton
    If TypeOf m_buttonLocal Is MSForms.CommandButton Then _
        Debug.Print "m_buttonLocal Is MSForms.CommandButton"

    If TypeOf m_buttonMsForms Is CommandButton Then _
        Debug.Print "m_buttonMsForms Is CommandButton"

    If TypeOf m_buttonLocal Is CommandButton Then _
        Debug.Print "m_buttonLocal Is CommandButton"

    If TypeOf m_buttonMsForms Is MSForms.CommandButton Then _
        Debug.Print "m_buttonMsForms Is MSForms.CommandButton"

End Sub

Output:

We have two instances of two different button types: testLocalButton and testMsButton
TypeName of both buton types returns same result
m_buttonLocal Is CommandButton
m_buttonMsForms Is MSForms.CommandButton