Is there something fundamentally wrong with the following design, or can anyone see why would the static properties sometimes loose their values ?
I have a class library project containing a class AppConfig; this class is consumed by a Webforms project.
The skeleton of AppConfig class is as follows:
Public Class AppConfig
Implements IConfigurationSectionHandler
Private Const C_KEY1 As String = "WebConfig.Key.1"
Private Const C_KEY2 As String = "WebConfig.Key.2"
Private Const C_KEY1_DEFAULT_VALUE as string = "Key1defaultVal"
Private Const C_KEY2_DEFAULT_VALUE as string = "Key2defaultVal"
Private Shared m_field1 As String
Private Shared m_field2 As String
Public Shared ReadOnly Property ConfigValue1() As String
Get
ConfigValue1= m_field1
End Get
End Property
Public Shared ReadOnly Property ConfigValue2() As String
Get
ConfigValue2 = m_field2
End Get
End Property
Public Shared Sub OnApplicationStart()
m_field1 = ReadSetting(C_KEY1, C_KEY1_DEFAULT_VALUE)
m_field2 = ReadSetting(C_KEY2, C_KEY1_DEFAULT_VALUE)
End Sub
Public Overloads Shared Function ReadSetting(ByVal key As String, ByVal defaultValue As String) As String
Try
Dim setting As String = System.Configuration.ConfigurationManager.AppSettings(key)
If setting Is Nothing Then
ReadSetting = defaultValue
Else
ReadSetting = setting
End If
Catch
ReadSetting = defaultValue
End Try
End Function
Public Function Create(ByVal parent As Object, ByVal configContext As Object, ByVal section As System.Xml.XmlNode) As Object Implements System.Configuration.IConfigurationSectionHandler.Create
Dim objSettings As NameValueCollection
Dim objHandler As NameValueSectionHandler
objHandler = New NameValueSectionHandler
objSettings = CType(objHandler.Create(parent, configContext, section), NameValueCollection)
Return 1
End Function
End Class
The Static Properties get set once on application start, from the Application_Start event of the Global.asax
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
//Fires when the application is started
AppConfig.OnApplicationStart()
End Sub
Thereafter, whenever we want to access a value in the Web.Config from anywhere, e.g. aspx page code-behind or another class or referenced class, we simply call the static property.
For example,
AppConfig.ConfigValue1()
AppConfig.ConfigValue2()
This is turn returns the value stored in the static backing fields m_field1, m_field2
Problem is sometimes these values are empty string, when clearly the Web.Config entry has values.
Is there something fundamentally wrong with the above design, or is it reasonable to expect the static properties would keep their value for the life of the Application session?
