ConnectivityStatus.IsOffline Property

 

Gets or sets a value indicating whether an application is in offline mode.

Namespace:   System.Web.ClientServices
Assembly:  System.Web.Extensions (in System.Web.Extensions.dll)

Public Shared Property IsOffline As Boolean

Property Value

Type: System.Boolean

true if the application is in offline mode; otherwise, false.

When you set the IsOffline property, the ConnectivityStatus class caches the value to the local file system. The client service providers in the System.Web.ClientServices.Providers namespace check this value to determine whether to use the offline data cache instead of attempting to access the associated Microsoft Ajax authentication, roles, and profile services.

The following example code demonstrates how to use this property to update the offline status depending on a check box value. In this example, a CheckedChanged event handler updates the offline status. If the user sets the application to the online state, the event handler attempts to revalidate the user. However, if the authentication server is unavailable, the event handler returns the application to the offline state.

Private Sub workOfflineCheckBox_CheckedChanged( _
    ByVal sender As Object, ByVal e As EventArgs) _
    Handles workOfflineCheckBox.CheckedChanged

    ConnectivityStatus.IsOffline = workOfflineCheckBox.Checked
    If Not ConnectivityStatus.IsOffline Then

        Try

            ' Silently re-validate the user.
            CType(System.Threading.Thread.CurrentPrincipal.Identity,  _
                ClientFormsIdentity).RevalidateUser()

            ' If any settings have been changed locally, save the new
            ' new values to the Web settings service.
            SaveSettings()

            ' If any settings have not been changed locally, check 
            ' the Web settings service for updates. 
            My.Settings.Reload()

        Catch ex As System.Net.WebException

            MessageBox.Show( _
                "Unable to access the authentication service. " & _
                Environment.NewLine + "Staying in offline mode.", _
                "Warning", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            workOfflineCheckBox.Checked = True

        End Try

    End If
End Sub

.NET Framework
Available since 3.5
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