CODEWITHSUNDEEP
c#winformslistbox
bred_one
bred_one

Reputation: 147

Async method in winforms doesn't works

I've got Listbox on main form, and i'd like to call method in second thread with access to listbox. Code:

class SecThreadOp
{
   public Thread thr1;
    private ListBox listb1= new ListBox();
    public SecThreadOp(ListBox lb)
    {
        thr1 = new Thread(write);
        listb1 = lb;
    }

    public void write()
    {
        if (listb1.InvokeRequired)
        {
            listb1.Invoke(new Action(write));
        }
        else
        {
            for (int i = 0; i < 20; i++) 
            {
                listb1.Items.Add("testing");
                Thread.Sleep(2000);
            }
        }
    }

}

and in main form i ve got:

.........
SecThreadOp sc;
.........
sc = new SecThreadOp(this.listBox1);
.........
private void button1_Click(object sender, EventArgs e)
   {
       sc.thr1.Start();
   }

Application suspend after click button, but i want to display 'test' in listbox async.

Thanks

Upvotes: 0

Views: 153

Answers (1)

Cam Bruce
Cam Bruce

Reputation: 5689

It looks like you're just re-calling write() in your background thread. In your Invoke, I'm assuming you want to update the ListBox on the UI thread. Do something like this:

 listb1.Invoke((MethodInvoker)delegate {  listb1.Items.Add("testing"); });

Upvotes: 1

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