Hi guys,

I'm developing a Winforms application (C#, .NET 2.0) with VS 2008.

All of a sudden the designer tells me the The ConnectionString property has not been initialized. when I open one of my forms.

This is the corresponding call stack:

at System.Data.OleDb.OleDbConnection.PermissionDemand()
at System.Data.OleDb.OleDbConnectionFactory.PermissionDemand(DbConnection outerConnection)
at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
at System.Data.OleDb.OleDbConnection.Open()
at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.ExecuteSingleRowRetrievalQuery(IRetrievalQuery queryToExecute, ITransaction containingTransaction, IEntityFields fieldsToFill, IFieldPersistenceInfo[] fieldPersistenceInfos)
at SD.LLBLGen.Pro.ORMSupportClasses.DaoBase.PerformFetchEntityAction(IEntity entityToFetch, ITransaction containingTransaction, IPredicateExpression selectFilter, IPrefetchPath prefetchPathToUse, Context contextToUse, ExcludeIncludeFieldsList excludedIncludedFields)
at eposbox2_DAL.DaoClasses.Lok_BenutzerDAO.FetchLok_BenutzerUsingUCBen_BenSl(IEntity entityToFetch, ITransaction containingTransaction, String ben_BenSl, IPrefetchPath prefetchPathToUse, Context contextToUse, ExcludeIncludeFieldsList excludedIncludedFields) in P:\SVN\Explidia\eposbox2\DAL\DaoClasses\Lok_BenutzerDAO.cs:line 67
at eposbox2_DAL.EntityClasses.Lok_BenutzerEntity.FetchUsingUCBen_BenSl(String ben_BenSl, IPrefetchPath prefetchPathToUse, Context contextToUse, ExcludeIncludeFieldsList excludedIncludedFields) in P:\SVN\Explidia\eposbox2\DAL\EntityClasses\Lok_BenutzerEntity.cs:line 382
at eposbox2_DAL.EntityClasses.Lok_BenutzerEntity.FetchUsingUCBen_BenSl(String ben_BenSl) in P:\SVN\Explidia\eposbox2\DAL\EntityClasses\Lok_BenutzerEntity.cs:line 343
at eposbox2.BAL.Benutzer..ctor(String pBenSl) in P:\SVN\Explidia\eposbox2\APP\BAL\Benutzer.cs:line 245
at eposbox2.BAL.ApplicationManager..cctor() in P:\SVN\Explidia\eposbox2\APP\BAL\ApplicationManager.cs:line 92  

All I'm doing in Benutzer.cs line 245 is:

   public Benutzer(string pBenSl)
    {
        _Entity = new Lok_BenutzerEntity();
        _Entity.FetchUsingUCBen_BenSl(pBenSl);  <--- line 245

What I don't understand: this happens while I'm in design mode. On runtime everything is fine. And this stuff has not been a problem for weeks. Suddenly just appeared.

Has anybody experienced such a problem before?

Is app.config still in the project and being copied to the correct folder on build...?

Matt

Hi Matt,

thanks for your reply!

Yes sure. The app.config is in the source code folder and contains a valid connection string.

<?xml version="1.0"?>
<configuration>
  <appSettings>
    <add key="Main.ConnectionString" value="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=P:\SVN\Explidia\eposbox2\RUN\eposbox2.mdb;User Id=;Password=;Jet OLEDB:System Database=;Jet OLEDB:Database password="/>

On Build the app.config is automatically copied to the output folder (of course with a different name: eposbox2.exe.config). Everything is fine on runtime.

It's a design time thing. You are triggering lazy-loading on the constructor of the class. This should fix the situation:

public Benutzer(string pBenSl)
{
    if( !DesignMode ) 
    {
        _Entity = new Lok_BenutzerEntity();
        _Entity.FetchUsingUCBen_BenSl(pBenSl);
        ...
    }
}

Ref: http://llblgen.com/tinyforum/Messages.aspx?ThreadID=13773&StartAtMessage=0&#76784

Hi daelmo,

hm, that's interesting. And actually, I already tried to make sure I'm not executing that code while being in design mode.

However, I didn't use the <DesignMode> property, because the code that forces the error is not within a control but rather in a simple class. So instead I used the following code.

 public static bool IsDesignMode
{
   get
   {
      return (System.ComponentModel.LicenseManager.UsageMode ==System.ComponentModel.LicenseUsageMode.Designtime);
   }
}

public Benutzer(string pBenSl)
{
     if( !IsDesignMode ) 
    {
        _Entity = new Lok_BenutzerEntity();
        _Entity.FetchUsingUCBen_BenSl(pBenSl);
        ...
    }
}

But this didn't help much. I was still getting the design time exception.

What I really don't understand: As far as I can see the code in the <Benutzer> class is not related at all to the WinForm that fires the exception.

Benutzer is a member of a static class called ApplicationManager. The constructor of this class is the only place where I call the constructor of the Benutzer class.

static ApplicationManager()
{
    if (!IsDesignMode)
    {
        //Create Benutzer instance for the logged user
        AktuellerBenutzer = new Benutzer(WinUser.UserName);
    }
}

As you can see I wrapped the call to the Benutzer constructor with <!IsDesignMode> again.

So the question is: maybe my IsDesignMode method just does not work?

Anyways: I understand this is not an LLBL issue in the proper sense. But if any of you guys had another ti I would very much appreciate this. Working on this form is becoming really annoying...

Thanks so much!

Instead of your IsDesignMode property please try the windows forms DesignMode property as David showed.

Is there a chance to use the windows forms <DesignMode> property within a class that is not a control?

As I already wrote, that was the only reason why I had to write my own <IsDesignMode> property. But maybe I'm missing something?

Your class must have been used from within a control or a form, that where you should pass the value of Component.DesignMode to the class, maybe through the CTor of the class.

Bottom line, you should find a way to read this value or pass it to the class.

Thanks guys! It's working again. Component.DesignMode did the trick.