通过变量名访问 VB.Net 结构元素

Question

好的，一些继承的代码：我有一个具有全部权限的结构：

public structure Perms
    dim writeStaff as Boolean
    dim readStaff as Boolean
    dim writeSupervisor as Boolean
    dim readSuperVisor as Boolean
    ' ... and many more
End Structure

我想要一个函数 canDo，我是这样创建的：

public function canDo(p as Perms, whichOne as String) as boolean
    Dim b as System.Reflection.FieldInfo
    b = p.GetType().GetField(whichOne)
    return b
end function

我用预填充的结构和 "writeSupervisor" 参数调用 canDo

在调试中，b 显示为 {Boolean writeSupervisor}，但是当我尝试将 return b 作为布尔值时，出现错误：类型 'System.Reflection.FieldInfo' 的值无法转换为 'Boolean'.

关于如何通过元素名称和测试/比较/return 值 "index" 进入结构的任何想法？

Answer 1

您需要调用GetValue method of the FieldInfo对象来获取字段值。

Public Function canDo(p As Perms, whichOne As String) As Boolean
    If (Not String.IsNullOrEmpty(whichOne)) Then
        Dim info As FieldInfo = p.GetType().GetField(whichOne)
        If (Not info Is Nothing) Then
            Dim value As Object = info.GetValue(p)
            If (TypeOf value Is Boolean) Then
                Return DirectCast(value, Boolean)
            End If
        End If
    End If
    Return False
End Function

我还建议您阅读此内容：Visual Basic Naming Conventions。

通过变量名访问 VB.Net 结构元素

Access VB.Net structure element by variable name

vb.net

reflection

structure