PropertyBag

Dim objPB As PropertyBagDim strValueToPersist As StringPrivate Sub Command1_Click()strValueToPersist = "TestingPersist"Set objPB = New PropertyBagCall objPB.WriteProperty("PersistValue", strValueToPersist, vbNullString)'　　 为了能够实现从PropertyBag读取数据，可以使用ReadProperty方法。'这一方法的参数包含有一个属性名称和一个缺省的数值，返回值是属性的数值：'strValueToPersist = objPB.ReadProperty("PersistValue", vbNullString)MsgBox objPB.ReadProperty("PersistValue", vbNullString)'　　 为了保存PropertyBag对象的内容，可以将内容属性保存到一个二进制字节的数组或一个变量。''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Dim vntContents As Variant'vntContents = objPB.Contents''　　 注释：Save to desired location'''''　　 为了能够从PropertyBag对象中重新获取信息，将保存数值读入一个二进制的数组。''然后将内容属性设置为二进制数组，这样所有的属性数值将可以重新获得。''Dim b() As Byte'Dim vntContents As Variant'''　　 注释：Read saved contents into vntContents from saved location''Set objPB = New PropertyBag'b = vntContents'objPB.Contents = bEnd SubPrivate Sub Command2_Click()' Class1 MySettingDim obj, obj2 As Class1Set objPB = New PropertyBagSet obj = New Class1obj.MySetting = "hello Class1"Call objPB.WriteProperty("PersistValue", obj, Nothing)Set obj = Nothingobj2 = objPB.ReadProperty("PersistValue", Nothing)MsgBox obj2.MySettingEnd SubPrivate Sub Command1_Click()Dim obj As PersistDim pb As PropertyBagSet obj = New PersistDebug.Print 1 & ":" & obj.MySettingobj.MySetting = "Testing"Debug.Print 2 & obj.MySettingSet pb = New PropertyBag'注释: Save objectCall pb.WriteProperty("PersistSample", obj)Set obj = Nothing'注释: Restore objectSet obj = pb.ReadProperty("PersistSample")Debug.Print 3 & obj.MySettingEnd SubPrivate cstrMySetting As String'当Class_InitProperties第一次建立时即初始化类中的属性:Private Sub Class_InitProperties()    cstrMySetting = vbNullStringEnd Sub'在每一个属性中，Property Let函数调用PropertyChanged，将把这一属性标记为“dirty”。'如果任一属性被标记为“dirty”，Class_WriteProperties函数即被调用，过程如下所示：Public Property Let MySetting(ByValNewValue As String)    cstrMySetting = NewValue    PropertyChanged "MySetting"End PropertyPublic Property Get MySetting() As String    MySetting = cstrMySettingEnd Property'Class_ReadProperties函数可以从一个属性标签中返回一个对象的值:Private Sub Class_ReadProperties(PropBag As PropertyBag)    cstrMySetting = PropBag.ReadProperty("MySetting", vbNullString)End Sub'Class_WriteProperties函数将数值写入到属性标签:Private Sub Class_WriteProperties(PropBag As PropertyBag)    Call PropBag.WriteProperty("MySetting", cstrMySetting, vbNullString)End Sub