CODEWITHSUNDEEP
c#
karthik
karthik

Reputation: 4741

Problem While receiving events from a thread

I'm Doing a project on FileTransfer in which i have a listview , i will get events from one of my class file for updating the percentage of the file sent so far,after receiving it i will place the percentage in my listview ,while doing that the listview got a flickering effect how to avoid it.i used application.doevents() but it doesnt works. i have seen in torrents while updating the percent the list doesnt get flickered how to achieve this .

void Sender_Progress(int CurrentValue, string Ip) // here im receiving Events
    {
        try
        {
            //if (CurrentValue == 1)
            //    UpdateTimer.Enabled = true;
            //list_send.Items[CurrentValue].SubItems[4].Text = Ip.ToString();
            //Application.DoEvents();
            obj = new object[] {CurrentValue,   Ip };
            list_send.Invoke(new UpdateList(UpList), obj);

        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
    public void UpList(int Val, string ind) // here im updating the listview
    {
        Application.DoEvents();
        int index = 0;
        index = Convert.ToInt32(ind);
        index = index - 1;
        list_send.Items[index].SubItems[4].Text = Val.ToString();
        if (Val == 100)
        {
            list_send.Items[index].SubItems[2].Text = "Completed.";
            //UpdateTimer.Enabled = false;
        }
        //Application.DoEvents();
    }

Upvotes: 1

Views: 105

Answers (3)

karthik
karthik

Reputation: 4741

i overcome the flickering effect succesfully,im getting events frequently ,i will get an integer everytime, i will store it in a variable and compare it with next variable received by the event if it matches i wont invoke the listview,otherwise i will invoke it.now the flickering goes away. thanks all.

Upvotes: -1

Marc Gravell
Marc Gravell

Reputation: 1063884

Firstly, you don't need the DoEvents, since you are already correctly working on two threads. Remove that. After that, I expect the problem is simply doing too much too quickly. Is it possible to batch updates, and only send an update, say, every 20? 50? times? It isn't clear what the control is, but many have multiple-update modes; for example with ListView:

    theList.BeginUpdate();
    try {
        // make multiple updates here...
    } finally {
        theList.EndUpdate();
    }

I would then see about passing over a list of updates, say, every 20 times (unless each takes a considerable time) [note it must be a different list per Invoke, and you need to remember to send any remaining items at the end, too].

Upvotes: 2

Dror Helper
Dror Helper

Reputation: 30819

Use worker thread - it's available from the toolbox and has two events that are invoked in the main (UI) thread.

The Progress event can be used to signal the listbox that it need to refresh or that the task was completed.

Upvotes: 0

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