'System.OutOfMemoryException' : Error creating window handle

Question

I'm coding a medium winforms application... every now and then on creation of certain Forms i get this exception.

I resolved it in the past but without proper udnerstanding of what is going on...

The puzzling part is that everything worked fine yesterday when I finnished this form and tested it, now I get this:

An unhandled exception of type 'System.OutOfMemoryException' occurred in System.Windows.Forms.dll

Additional information: Error creating window handle.

Exception is thrown in this block of code:

    public partial class PonovniIspisRacunaForm : Form
        {    

        DataTable dnevniPrometTable;
        DataTable kontrolnaTrakaTable;
        DataTable ukupniDnevniPrometTable;
        DataTable stavkeRacunaTable;
        ZisCode.Hibernate.Mdb.DataModel dnevniPrometDataModel;
        ZisCode.Hibernate.Mdb.DataModel kontrolnaTrakaDataModel;
        OsnovniPodaci.Porezi.Stope stope;
        string brojRacuna;
        string ZKI;
        string JIR;
        string Operator;
        //decimal ukupno = 0.00m;

        decimal tarifa;
        decimal kolicina;
        decimal iznos;
        decimal porez;
        decimal porez25;
        decimal porez05;
        decimal porez13;
        decimal povratnaUkupno;
        decimal osnov25;
        decimal osnov05;
        decimal osnov13;
        //decimal nabavna; 

        PrintDocument printDocument;

        public PonovniIspisRacunaForm()
        {
            InitializeComponent();
        }

    private void FinancijskiRekapitular_Load(object sender, EventArgs e)
            {
                stope = new OsnovniPodaci.Porezi.Stope();

                // popunjava današnji datum
                this.dtpDatum.Value = DateTime.Today;

                // Get Data Table za određeni datum:
                dnevniPrometDataModel = ZisCode.DataModels.Get("DnevniPromet");
                kontrolnaTrakaDataModel = ZisCode.DataModels.Get("KontrolnaTraka");

                PrintSetup();

                ukupniDnevniPrometTable = MergeDnevniKontrolna();
                if (ukupniDnevniPrometTable.Rows.Count != 0)
                {
                    FillComboBox();
            }
        }
    private void FillComboBox()
            {
                cbBrojRacuna.DataSource = ZisCode.Methods.DataTableOperations.SortDataTable(ukupniDnevniPrometTable, "Dokument", "DESC") // orderbydescending
                    .AsEnumerable().GroupBy(row => row.Field<string>("Dokument")).Select(group => group.First()).CopyToDataTable(); // groupby brojRacuna-Dokument
                cbBrojRacuna.DisplayMember = "Dokument"; // Broj Računa
                cbBrojRacuna.ValueMember = "Dokument";
                cbBrojRacuna.SelectedIndex = 0;
            }

            private void PrintSetup()
            {
                // priprema za ispis
                printDocument = new PrintDocument();
                printDocument.DefaultPageSettings.PaperSize = new PaperSize("Racun size", 295, 500);
                printDocument.PrintPage += new System.Drawing.Printing.PrintPageEventHandler(CreateRekapitular);
                // uklanja poruku dialog box (printing ..) kod ispisa
                PrintController printController = new StandardPrintController();
                printDocument.PrintController = printController;
                // popravlja font
                printPreview.UseAntiAlias = true;
            }
}

to be more specific this line: this.dtpDatum.Value = DateTime.Today; Why?? I have no idea...

I tried seting dateTimePicker in constructor and I got different exception unrelated to window handle.

I've read about this case on other questions but nothing really clicked for me.

Winforms issue - Error creating window handle

Error Creating Window Handle

These two answers don't help me since answers are to ambiguous and expect me to know how dispose is supposed to work in first place. Help, I'm a n00b!

UPDATE Posted Almost all code of the class as I was asked

Can you add some code for PrintSetup and FillComboBox() ? Do you have some general variables and what do you do on Closing the form? — Wai Fung Au Yeung, Apr 27 '17 at 13:10
@WaiFungAuYeung yes I do have bunch of variables and on closing the form I don't dispose lol how should I do it? Even though this exception is thrown when loading the form — solujic, Apr 28 '17 at 07:44

score 4 · Answer 1 · answered Apr 27 '17 at 13:54

A window handle is an unmanaged resource. There are only so many of them. If you don't free those handles, Windows will run out and you will get exceptions.

Classes that use native HANDLEs will need to free them when they are no longer needed. Those classes will implement IDisposable. You should look into this, it's a core part of .NET and crucial to working with unmanaged resources like handles.

Turn on your static code analysis (Right click on Project -> Properties -> Code Analysis and select Enable on build and pick Microsoft all rules) and fix all violations, especially those non-disposed IDisposables.

nvoigt thanks for reply, I didn't know this option even exists - now I feel like big n00b... — solujic, Apr 27 '17 at 14:05

score 1 · Answer 2 · edited May 23 '17 at 11:54

1

Since your exception is OutOfMemory it may be that you are just out of memory. Check task manager to see how much memory you have available and I would suggest to run your app through some memory profiler like RedGate or something similar to see where the leak is. In case of dispose take a look at this asnwer for more info C# Form.Close vs Form.Dispose

edited May 23 '17 at 11:54

Community

1
1

answered Apr 27 '17 at 13:45

chehh984

121
4

1

I don't think that's the problem, could it be that dateTimePicker didn't dispose (?!) since it is a custom user control... im not sure im just guessing voer here because dtp is the source of exception – solujic Apr 28 '17 at 07:33

score 0 · Answer 3 · answered May 02 '17 at 10:54

0

The problem was private void

dtpDatum_TextChanged(object sender, EventArgs e)
{
    ukupniDnevniPrometTable = MergeDnevniKontrolna();
    FillComboBox();
}

I guess this event was fired up too many times and caused memory leak

answered May 02 '17 at 10:54

solujic

924
1
18
43

'System.OutOfMemoryException' : Error creating window handle

3 Answers3