VB.NET 表单设计器文件中的 Dispose 方法

Question

<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
    Try
        If disposing AndAlso components IsNot Nothing Then
            components.Dispose()
        End If
    Finally
        MyBase.Dispose(disposing)
    End Try

谁能告诉我为什么我们在designer.vb 中使用它？

Answer 1

Dispose 用于释放不受运行时管理的资源（非托管资源）。这包括文件、流、字体等。当不再使用该对象时，garbage collector 会自动释放分配给托管对象的内存。但是，无法预测垃圾收集何时发生。此外，垃圾收集器不了解非托管资源，例如窗口句柄或打开的文件和流。

在您的代码中，基类的Dispose 方法被子类实现覆盖，因此overriden 关键字调用Mybase.Dispose。基类是IContainer，子类是Form。 Dispose 方法在IDisposable 接口中可用。

在designer.vb 中，当在表单上调用Dispose 时，此自动生成 代码用于在表单的组件上调用Dispose，即在处置表单时，也处置其组件.

<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
    Try
        ' If Dispose() has been called explicitly free both managed and 
        ' unmanaged resources (disposing = true)
        ' and there are components in the form
        If disposing AndAlso components IsNot Nothing Then 
            ' Free the resources used by components
            components.Dispose()
        End If
    Finally
        ' Once done disposing the current form's resources, 
        ' dispose the resources held by its base class 
        ' Finally clause executes this code block (to dispose base class)
        ' whether or not an exception has been encountered while 
        ' disposing the resources in the form
        MyBase.Dispose(disposing)
    End Try

更多信息

• Form.Dispose Method (Boolean)
• Implementing Finalize and Dispose to Clean Up Unmanaged Resources
• What's that "Windows Form Designer generated code" anyway?
• C# Finalize/Dispose pattern
• Dispose vs Dispose(bool)