A static property that loses its value intermittently?

Question

Is there something fundamentally wrong with the next design, or can someone understand why static properties sometimes lose their meaning?

I have a class library project containing an AppConfig class; this class is used by the Webforms project.

The skeleton of the 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

Static properties are set once at application startup, from the Application_Start event for Global.asax

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)

    //Fires when the application is started
    AppConfig.OnApplicationStart()

End Sub

After that, whenever we want to access a value in Web.Config from anywhere, for example. aspx page code-behind or another class or reference class, we just call the static property.

For instance,

AppConfig.ConfigValue1()
AppConfig.ConfigValue2() 

This rotation returns the value stored in the static backup fields m_field1, m_field2

, , Web.Config .

- , , ?

Answer 1

, Application_Start Global.asax

. ,

Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs)
        AppConfig.OnApplicationStart() 
End Sub

: Session_Start, ( !).

Application_Start, .

IIS, , ?

Answer 2

/ , , . .

( , ).

return defaultValue

:

ReadSetting = defaultValue