CODEWITHSUNDEEP
c#visual-studio
Dejan Dozet
Dejan Dozet

Reputation: 1009

Variables keep resetting to null in C# application, why?

I am building a desktop app. In Program.cs I have this:

public struct Settings
{
     public string SiteName;
     public string IP3Oktets;
     public string Data_Source;
     public string Initial_Catalog;
     public string officialCardNumber;
     public bool KarticaUcitacu;
     public Dictionary<string, object> KarticuUbacio;
     public Dictionary<string, object> Korisnik;
     public Dictionary<string, object> PoslednjiUgovor;
     public Version Version;
     public string userName;
}

public static Settings mySettings = new Settings();

So only one object to hold app-wide properties.

Then during the logon process I set them up - a procedure that gets data from the database looks like this:

public static Dictionary<string, object> IzŠifreKartice(string pKartica)
{
     SqlParameter[] @params =
     {
         new SqlParameter("@KARTICA", SqlDbType.VarChar, 15) { Value = pKartica },
     };

     DataTable dt = DB.GetData("SELECT * FROM ZAPOSLENI WHERE KARTICA = @KARTICA", @params);

     if (dt.Rows.Count == 1)
     {
          return dt.Rows[0].Table.Columns
                   .Cast<DataColumn>()
                   .ToDictionary(c => c.ColumnName, c => dt.Rows[0][c]);  ;
     } 
     else
     {
          return null;
     }
}

Now, based on some condition I have to open another login prompt and I do it like this (I also show here the main form):

    this.Hide();
    var form2 = new frm_glavna(); //main form
    form2.Closed += (ss, args) => this.Close();
    form2.Show();
    var form3 = new frm_RazduživanjeLogin(); //another login 
    form3.ActiveControl = form3.txt_Lozinka;

    form3.ShowDialog(this);

And after that, when the main form opens, I lose all Dictionary<string, object> values (they become null).

What I am doing wrong here? Is it possible that the program is keeping their references instead of values?

Thanks, Dejan

update:

enter image description here

enter image description here

FIXED!

I have found that this was causing problem:

Program.Settings s = Program.mySettings;

it seems that this actually copy object somehow instead just keeping a reference on mySettings variable, so I remove it. I will use Program.mySettings even if that is much more to write.

Thanks

Upvotes: 0

Views: 571

Answers (1)

AKX
AKX

Reputation: 168834

You can change the Settings type from a struct to a class, and C# won't copy it on assignment anymore.

Upvotes: 1

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