如何从vb.net中的模块访问表单变量 [英] How do you access form variable from a module in vb.net

问题描述

如何从vb.net中的模块访问表单变量?

解决方案

将表单变量声明为public.

<首先，应将变量声明为public(从不同程序集的同一程序集访问)或internal(从同一程序集的访问，因此应更频繁地使用).该变量"实际上应该是成员，可以是字段，也可以是属性.通常，正确的封装要求它是属性，而不是字段.从外部访问任何字段都被认为是不好的编码风格.

如果成员是static，则可以从外部以MyModule.MyMember身份访问它.如果这是一个实例成员(非静态)，则需要具有该模块的实例(通过在某个地方调用的构造函数，该实例将返回对该实例的引用)，并以MyInstance.MyMember的形式进行访问.

—SA

如果不引用该类的实例，则无法直接访问该类.您最好的选择可能是这样的:

 模块 Module1
    私有 m_MyForm  As  Form1
    公共 只读 属性 MyForm() As  Form1
        获取
            如果 IsNothing(m_MyForm)然后 m_MyForm = 新建 Form1
            返回 m_MyForm
        结束 获取
    结束 属性
    公共 子 WriteLog( ByVal  txt  As  字符串)
        MyForm.TextBox3.Text + = txt + vbNewLine
    结束 子
结束 模块 

现在，您可以在应用程序中的任何位置使用Module1.MyForm访问Form1.

How do you access form variable from a module in vb.net?

解决方案

Declare the form variable as public.

First, the variable should be declared public (to access from the same of different assembly) or internal (to access from the same assembly, so it should be used more often). This "variable" is actually should be a member, either a field or a property. Usually, proper encapsulation requires it to be a property, not a field. Having any fields accessible from outside is considered a bad coding style.

If the member is static, you access it from outside as MyModule.MyMember. If this is an instance member (non-static), you need to have an instance of the module (via a constructor you call somewhere which returns you the reference to the instance), and access it as MyInstance.MyMember.

—SA

You cannot directly access a class without a reference to an instance of that class. Your best bet might be something like this:

Module Module1
    Private m_MyForm As Form1
    Public ReadOnly Property MyForm() As Form1
        Get
            If IsNothing(m_MyForm) Then m_MyForm = New Form1
            Return m_MyForm
        End Get
    End Property
    Public Sub WriteLog(ByVal txt As String)
        MyForm.TextBox3.Text += txt + vbNewLine
    End Sub
End Module

Now anywhere in your application you can access Form1 using Module1.MyForm.

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