Question

I have an application that uses Process.Start to execute an exe. It works fine for all the .exe that I have tested except when the .exe has a configuration file where it gets a connectionstring, when this happens I get a System.NullReferenceException. this is my code.

to execute the exe:

string eucApp = @"C:\Temp\app.exe"
startInfo = new ProcessStartInfo(eucApp);
using (Process execProcess = Process.Start(startInfo))
{
    execProcess.WaitForExit();
}

then the exe starts and the first thing that does is get the a connection string with this code line

strCadena = ConfigurationManager.ConnectionStrings("ConnectionString")

If I replace this with the connectionstring like this, it works fine

strCadena = "Data Source=HostName;Initial Catalog=MyDB;Integrated security=True"

I would remove the config file and put its values into the .exe code but the trouble is that I have more than 500 .exe’s that uses config files so if any one knows a way to avoide this please tell me!

Answer 1

thanks for your help. I figured out the problem. Somehow the .exe was pointing to the app.config of the aplication that start’s the process. I added this class to the .exe that is developed in VB .Net

Imports System.Configuration
Imports System.Reflection
Public Class AppConfig
  Implements IDisposable
  Public Shared Function Change(ByVal path As String) As AppConfig

    Return New ChangeAppConfig(path)
  End Function
  Public Overridable Sub Dispose() Implements IDisposable.Dispose
  End Sub
  Private Class ChangeAppConfig
    Inherits AppConfig
    Private ReadOnly oldConfig As String = AppDomain.CurrentDomain.GetData("APP_CONFIG_FILE").ToString
    Private disposedValue As Boolean
    Public Sub New(ByVal path As String)
      AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", path)
      ResetConfigMechanism()
    End Sub
    Public Overrides Sub Dispose()
      If (Not disposedValue) Then
        AppDomain.CurrentDomain.SetData("APP_CONFIG_FILE", oldConfig)
        ResetConfigMechanism()
        disposedValue = True
      End If
      GC.SuppressFinalize(Me)
    End Sub
    Private Shared Sub ResetConfigMechanism()

      GetType(ConfigurationManager).GetField("s_initState", BindingFlags.NonPublic Or BindingFlags.Static).SetValue(Nothing, 0)
      GetType(ConfigurationManager).GetField("s_configSystem", BindingFlags.NonPublic Or BindingFlags.Static).SetValue(Nothing, Nothing)
      Dim assemblies() As Type = GetType(ConfigurationManager).Assembly.GetTypes()
      For Each assembly As Type In assemblies
        If (assembly.FullName = "System.Configuration.ClientConfigPaths") Then
          assembly.GetField("s_current", BindingFlags.NonPublic Or BindingFlags.Static).SetValue(Nothing, Nothing)
          Exit For
        End If
      Next
    End Sub
  End Class
End Class

I call Change function at the begining of the program

AppConfig.Change(Application.StartupPath & "\app.exe.Config")

This way it take the right config file