Question

我正在使用PropertyGrid控件来编辑我的类属性，并且我尝试将某些属性设置为只读，具体取决于其他属性设置。

这是我班级的代码：

Imports System.ComponentModel
Imports System.Reflection

Public Class PropertyClass

    Private _someProperty As Boolean = False

    <DefaultValue(False)>
    Public Property SomeProperty As Boolean
        Get
            Return _someProperty
        End Get
        Set(value As Boolean)
            _someProperty = value
            If value Then
                SetReadOnlyProperty("SerialPortNum", True)
                SetReadOnlyProperty("IPAddress", False)
            Else
                SetReadOnlyProperty("SerialPortNum", False)
                SetReadOnlyProperty("IPAddress", True)
            End If
        End Set
    End Property

    Public Property IPAddress As String = "0.0.0.0"

    Public Property SerialPortNum As Integer = 0

    Private Sub SetReadOnlyProperty(ByVal propertyName As String, ByVal readOnlyValue As Boolean)
        Dim descriptor As PropertyDescriptor = TypeDescriptor.GetProperties(Me.GetType)(propertyName)
        Dim attrib As ReadOnlyAttribute = CType(descriptor.Attributes(GetType(ReadOnlyAttribute)), ReadOnlyAttribute)
        Dim isReadOnly As FieldInfo = attrib.GetType.GetField("isReadOnly", (BindingFlags.NonPublic Or BindingFlags.Instance))
        isReadOnly.SetValue(attrib, readOnlyValue)
    End Sub
End Class

这是我用来编辑值的代码：

    Dim c As New PropertyClass
    PropertyGrid1.SelectedObject = c

问题在于，当我将SomeProperty设置为True时，没有任何反应，当我再次将其设置为False时，它会设置所有属性只要。有人可以在我的代码中看到错误吗？

Answer 1

尝试使用ReadOnly属性装饰所有类属性：

<[ReadOnly](False)> _
Public Property SomeProperty As Boolean
  Get
    Return _someProperty
  End Get
  Set(value As Boolean)
    _someProperty = value
    If value Then
      SetReadOnlyProperty("SerialPortNum", True)
      SetReadOnlyProperty("IPAddress", False)
    Else
      SetReadOnlyProperty("SerialPortNum", False)
      SetReadOnlyProperty("IPAddress", True)
    End If
  End Set
End Property

<[ReadOnly](False)> _
Public Property IPAddress As String = "0.0.0.0"

<[ReadOnly](False)> _
Public Property SerialPortNum As Integer = 0

从此代码项目中找到它：Enabling/disabling properties at runtime in the PropertyGrid

为了使所有这些正常工作，将类的每个属性的ReadOnly属性静态定义为您想要的任何值都很重要。如果没有，那么在运行时以这种方式更改属性将错误地修改类的每个属性的属性。

在PropertyGrid中设置ReadOnly属性设置所有属性只读

1 个答案: