vb.net - CA2000：在失去作用域之前处置对象

Question

当我尝试在我的项目中运行代码分析时，我在这部分代码中遇到了错误。

//代码

  Private Sub SaveMaterialStatus(ByVal status As String)

        Dim cSMaterialInput As CSMaterialInput = Nothing

        Try

            If ViewState("CSInput") IsNot Nothing Then
                'Create a new transaction
                cSMaterialInput = New CSMaterialInput
                cSMaterialInput = ViewState("CSInput")
                cSMaterialInput.CSStatus = status
                CSMaterialInputMethods.SaveToDatabase(cSMaterialInput, Environment.UserName, Environment.MachineName)

            End If
        Catch ex As Exception
            Throw

        Finally
            If cSMaterialInput IsNot Nothing Then cSMaterialInput.Dispose()

        End Try
    End Sub

详细错误：

CA2000  Dispose objects before losing scope In method 'ShowSummary.SaveMaterialStatus(String)', call System.IDisposable.Dispose on object 'cSMaterialInput' before all references to it are out of scope.   xxxx.CostingTool.Presentation   ShowSummary.aspx.vb 790

我哪里错了？？

Answer 1

 cSMaterialInput = New CSMaterialInput

这就是问题开始的地方。您立即在下一个语句中重新分配变量，这样您创建的对象就不会被释放。这触发了 CA2000 警告。创建一个您从不使用的新对象是没有意义的。该方法几乎没有其他内容：

  Private Sub SaveMaterialStatus(ByVal status As String)
      Dim cSMaterialInput = ViewState("CSInput")
      If cSMaterialInput IsNot Nothing Then
          cSMaterialInput.CSStatus = status
          CSMaterialInputMethods.SaveToDatabase(cSMaterialInput, Environment.UserName, Environment.MachineName)
      End If
  End Sub

Nothing 测试仍然有明显的代码气味。当您的程序试图不保存任何内容时，它只是隐藏了一个错误。