strange NullReferenceException

Hi guys,

I get some strange NullReferenceException once in a while (see screenshot). The 'TempDatasource' variable is a Dictionary<int, DataItem>, where DataItem is a custom class. The variable 'rn' is an integer.

I'm using VS2010 & .Net 4. Could this be a bug in the framework?

What is the stack? Haven't you defined you own GetHashCode(), Equals() method in DataItem?

The DataItem class is a simple class that only contains some int and string properties. No methods defined. I created this class because I need to bind some data to a gridview from different sources.

Can you post the code?

(only the relevant code)

Code:

---

  public partial class cpm : System.Web.UI.Page {
    private bool completed = false;
    private Dictionary<int, DataItem> TempDatasource = new Dictionary<int, DataItem>();

    class DataItem {
      public int rn_number { get; set; }
      public int imps { get; set; }
      public string name { get; set; }
      public DateTime enddate { get; set; }
    }

    protected void Page_Load(object sender, EventArgs e) {
        Report report = new Report();
        report.Completed += Process;
        report.Run(); //runs the report async

        while (!completed)
          Thread.Sleep(50);
       
        //now the report is ready, load some data from the local database and set the name and enddata
        //...

        gridview1.DataSource = TempDatasource.Values;
        gridview1.DataBind();
    }

    void Process(API.ExecuteReportCompletedEventArgs<API.Reporting.Network> e) {
      if (e.error != null) {
        //log error
      }
      else {
        foreach (var item in e.result.Data) {
          int rn;
          if (RN.IsValid(item.line_item, item.line_item_id, out rn)) {
            if (!TempDatasource.ContainsKey(rn)) {
              TempDatasource.Add(rn, new DataItem());
              TempDatasource[rn].rn_number = rn;
            }
            TempDatasource[rn].imps += item.imps;
          }
        }
      }
      completed = true;
    }

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