Why the event listBox1_DrawItem is working only sometimes in some cases ?

In the designer I have set the listBox1 DrawMode property to: OwnerDrawVariable

Then in the Form1 Load event I did:

data.Add("Gpu Temeprature --- " + form1_location_on_x);           data
.Add("Cpu Temperature --- " + form1_location_on_y);
            listBox1.DataSource = data;

Then I have two events:

private void listBox1_MeasureItem(object sender, MeasureItemEventArgs e)
        {
            e.ItemHeight = 25;
        }

        private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
        {
            if (e.Index == -1)
            {
            }
            else
            {

                ColorText.ColorListBox(data, e);

            }
        }

I used a breakpoint on the line: ColorText.ColorListBox(data, e); and it's working it's getting to this line.

But I want to show some values that are changing each X seconds.

So I delete the code from the Load event and did:

In the cpuView method in Form1 :

private void cpuView()
        {
            if (pauseContinueDoWork == true)
            {
            }
            else
            {
                Computer myComputer = new Computer();
                myComputer = new Computer(settings) { CPUEnabled = 
true };

                myComputer.Open();
                Trace.WriteLine("");
                foreach (var hardwareItem in myComputer.Hardware)
                {
                    if (hardwareItem.HardwareType == 
HardwareType.CPU)
                    {
                        hardwareItem.Update();
                        foreach (IHardware subHardware in 
hardwareItem.SubHardware)
                            subHardware.Update();

                        foreach (var sensor in hardwareItem.Sensors)
                        {
                            settings.SetValue("sensor", 
sensor.Value.ToString());
                            if (sensor.SensorType == 
SensorType.Temperature)
                            {
                                sensor.Hardware.Update();
                                settings.GetValue("sensor", 
sensor.Value.ToString());
                                //label17.Text = 
sensor.Value.ToString() + "c";//String.Format("{0} Temperature = {1}c", sensor.Name, sensor.Value.HasValue ? sensor.Value.Value.ToString() : "no value");
                                if (InvokeRequired)
//this.Invoke(new Action(() => label17.Text = sensor.Value.ToString() + "c"));
data.Add("Gpu Temeprature --- " + sensor.Value.ToString());
                                else
                                    label17.Text = 
sensor.Value.ToString() + "c";
                                tempCpuValue = sensor.Value;
                                if (sensor.Value > 60)
                                {
Logger.Write("The Current CPU Temperature Is ===> " + sensor.Value);
                                    button1.Enabled = true;
                                }
                                int t = label17.Text.Length;
                                if (t >= 4)
                                {
                                    if (InvokeRequired)
this.Invoke(new Action(() => label17.Location = new Point(50,20)));

                                }
                                else
                                {
                                    
this.Invoke(new Action(() => label17.Location = new Point(50, 20)));
                                }
                                break;
                            }
                        }
                    }
                }
            }
        }

I changed in this method:

if (InvokeRequired)
                                    //this.Invoke(new Action(() => label17.Text = sensor.Value.ToString() + "c"));
                                    data.Add("Gpu Temeprature --- " + sensor.Value.ToString());

Then in the background do work event i did:

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = sender as BackgroundWorker;
            while (true)
            {
                if ((worker.CancellationPending == true))
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    if (tempCpuValue >= (float?)nud1.Value || tempGpuValue >= (float?)nud1.Value)
                    {
                        soundPlay = true;
                        blinking_label();
                        NudgeMe();
                    }
                    else
                    {
                        soundPlay = false;
                        stop_alarm = true;

                    }
                    cpuView();
                    gpuView();
                    listBox1.DataSource = data;
                    Thread.Sleep(1000);
                }
            }
        }

In this case the event draw item of the listBox1 is not working.

What I wanted is to update the first item in the listBox with the value sensor.Value

The problems are that each time it's adding a new sensor.Value to data(List<string>) instead updating the item. Second the measure item and draw item events are not working .