从主线程中调用一个函数并使它与主线程中的一个函数并行工作

Question

I really need your help in my issue very quickly and it's too close to the previous issue. I want to call a function using thread from the main thread.

for more explanaition, here is a sample from my code: // please look to the code begining from ( //------- )

    // this function is being called from the Form1 class Like this 
    //(this.Load += new System.EventHandler(this.Form1_Load);)

    private void Form1_Load(object sender, EventArgs e)
    {
        Common.MainForm = this;

        ftpServerIP = "74.220.215.77/ASGAQuraan";
        ftpUserID = "sanbouk@asgatech.com";
        ftpPassword = "asga_root";

        iStartConnection = true;
        iGetNarratorData = false;
        iGetNarratorsSuras = false;
        _isExpandedIndecies = new string[10];

        refreshPhons = true;
        count = 0;
        _btnDownload2PC.Enabled = false;
        _btnDownload2Phone.Enabled = false;

        //--------------------------------------------------------------------------------------
        //timer1.Tick() is a function which Gets Data rom Phone
        //Now, GetFromServer, and GetFromPC are 2 functions which i want to them 
        // to work in paralel with Timer1.Tick()
        //So, Fincally i want all 3 function work together with no gabs

         Timer1.Enabled = true;
        Timer1.Start();
        if (InvokeRequired)
        {
            Invoke(new GetFromServerHandler(GetFromServer));
        }
        else
        {
            ServerQuranTreeView.Nodes.Clear();
            GetFromServer();
            GetFromPC();
        }
    }

** NOTE: in GetFromServer and GetFromPC I will update on a Tree which is in the main thread Form1 (GUI) and when when I tried to use thread ( thread _t = new Thread(new ThreadStart(GetFromServer))) this error appears: " Action being performed on this control is being called from the wrong thread. Marshal to the correct thread using Control.Invoke or Control.BeginInvoke to perform this action. " **

I hope that I explained my problem well.

Thanks in advance.

Answer 1

You can't do operations on the UI from a different thread - but you could make GetFromServer and GetFromPC fetch the data on the other thread and then call Control.Invoke to get back to the UI thread to update the treeview.

See my threading article for example of doing background work in another thread and then marshalling back. The article was written pre-C#2, so these days it's slightly less clunky. You can also use BackgroundWorker to make it easier to report progress etc.

Answer 2

For any single operation that only fetches data and then updates GUI and then its done till next time someone invokes it, use BackgroundWorker.

Its a class that has simplified thread coding for you. That way you just write the code for fetching data in one function, and one method that displays the fetched data afterwards.

Then just call it whenever data is to be fetched.

BackgroundWorker is superb for any GUI solution where you click a button that does something in the background and updates something afterwards. It also supports updating the GUI as it fetches data.