How to modify UI elements from async c#

Question

I need to add in a form.listwiew some rows but i need to add them dinamyically while my async function is processing... I have read that is not possible to do this from an async method. Anyway i have to do this ... any other method or solution? Example:

private async Task start(CancellationToken token)
        {      
        try
        {
            await Task.Run(() =>
            {
             //do something and then modify UI
             Guiadjust("",1); //function that add rows

            },token);
        }catch (Exception ex)
        {
            if (ex is TaskCanceledException)
                CustomMessageBox.Show("Unaxpected error", ex.ToString());
        }
      }

Function to add rows to list graphical form element that doesn't work because called from async method, instead it should normally work!

private void Guiadjust(string cc, int ff)
{

    string[] row = { "Working", "", "" };
    var listViewItem = new ListViewItem(row);
    list.Items.Add(listViewItem);
}

Calling the function:

await start(cts.Token);

this doesn't work.... no rows are added from my async function. And i need to add rows dinamically to the UI — Programmer, Jun 12 '18 at 10:52
hint : you're looking for `Control.Invoke` : https://stackoverflow.com/questions/6650691/invoke-in-windows-forms — Timothy Groote, Jun 12 '18 at 10:53
You could update UI this way: `this.Invoke(() => list.Items.Add(listViewItem));` — Fabjan, Jun 12 '18 at 10:53
Cannot convert with invoke from System.....ListViewItem to System.Delegate — Programmer, Jun 12 '18 at 10:57
You _can_ update the GUI from an async method, but you _cannot_ update the GUI from a `Task.Run()`. You simplified too much to get a good answer. — bommelding, Jun 12 '18 at 11:00

How to modify UI elements from async c#

0 Answers0