似乎你有两个任务。定义表单的两个成员：

 

   任务t1 = null;

   任务t2 = null;

 

并分配任务，例如：

 

   t1 = Task.Factory.StartNew（...）;

 

然后试试这个：

 

   isRunning = false;

   t1？。等待（）;

   t2？。等待（）;

   this.Close（）;

 

I have a task thats doing some work in my form and I call it in the form load like so

bool isRunning = false;
        Stopwatch timeOutWatchA = new Stopwatch();

        private void Form1_Load(object sender, EventArgs e)
        {
            Task.Factory.StartNew(() =>
            {
                if (Settings.CurrentSettings.EnableA)
                    WeightReadingThreadA();
            });
        }
        private void WeightReadingThreadA()
        {
            SerialPort portA = new SerialPort();

            TimeOutA();
            timeOutWatchA.Start();

            try
            {
                portA.Open();
                if (portA.IsOpen)
                {

                    while (isRunning)
                    {
                        //Does something here
                        
                        this.Invoke(new Action(() =>
                        {
                            try
                            {
                                //display results to UI
                            }
                            catch (Exception)
                            {
                            }
                        }));

                        timeOutWatchA.Reset();
                        timeOutWatchA.Start();
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        private void TimeOutA()
        {
            Task.Factory.StartNew(() =>
            {
                while (isRunning)
                {
                    Thread.Sleep(1000);
                    if ((timeOutWatchA.ElapsedMilliseconds / 1000) > 3)
                    {
                        this.Invoke(new Action(() =>
                        {
                            try
                            {
                                //display message to UI
                                //This is where Iam getting
                                //the error when I try to 
                                //close the form
                            }
                            catch (Exception)
                            {
                            }
                        }));
                    }
                }
            });
        }

        private void BtnClose_Click(object sender, EventArgs e)
        {
            isRunning = false;
            this.Close();
        }

When I try and close the form I get the error "'Invoke or BeginInvoke cannot be called on a control until the window handle has been created". My question is how can i stop this error so i can close the form nicely. I have tried setting the variable isRunning to false before I close the form but this is not working

If you think it you can achieve it

Seems that you have two tasks. Define two member of the form:

 

   Task t1 = null;

   Task t2 = null;

 

and assign the tasks, for example:

 

   t1 = Task.Factory.StartNew( … );

 

then try this:

 

   isRunning = false;

   t1?.Wait();

   t2?.Wait();

   this.Close();