Question

I have a problem when reading a String list, here is my code.

public partial class form : Form
{
    public static List<String> errores = new List<String>();

   private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e){

        BackgroundWorker bw = sender as BackgroundWorker;

        // Extract the argument. 
        string arg = (string)e.Argument;

        // Start the time-consuming operation.
        //  e.Result =
        if (tags.prog2(arg) == false)
        {
            //guardar en lista de no completadas
            form.errores.Add("a");

        }
  //some code here
        }




    private void buscar()
    {

    //Some code here
        foreach (string i in rutas)
            {
                backgroundWorker1 = new System.ComponentModel.BackgroundWorker();

                backgroundWorker1.WorkerSupportsCancellation = true;
                backgroundWorker1.DoWork += new System.ComponentModel.DoWorkEventHandler(this.backgroundWorker1_DoWork);
                backgroundWorker1.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(this.backgroundWorker1_RunWorkerCompleted);
                backgroundWorker1.RunWorkerAsync(i);                    


            }
          foreach (string prime in form.errores)
            {
                MessageBox.Show(prime);
            }
    }
}

but there is no elements in the list, why its happening this?

Obviously I call both functions

Aclaration
function1 its a backgroundWorker, so its called too many times, I dont know if this is related to the error.

Answer 1

Aclaration function1 its a backgroundWorker, so its called too many times, I dont know if this is related to the error

Seems read() is called before function1() call. As function1 is called by BackgroundWorker it is quite possible.

You should keep a flag to indicate whether function1 is called or not. If not called, you should take preventive action.

For the reference, following code is running well (and producing "aaa" output)

form f = new form(); 
f.Test();

---

public partial class form 
{
    public static List<String> errores = new List<String>();

    private void function1()
    {
        form.errores.Add("aaa");
    }

    //Now I try to read it in other function.

    private void read()
    {
        foreach (string i in form.errores)
        {
            Console.WriteLine(i);
        }
    }

    public void Test()
    {
       function1();
       read();
    }
}