C# : How to pause the thread and continue when some event occur?

You could use a System.Threading.EventWaitHandle.

An EventWaitHandle blocks until it is signaled. In your case it will be signaled by the button click event.

private void MyThread()
{
    // do some stuff

    myWaitHandle.WaitOne(); // this will block until your button is clicked

    // continue thread
}

You can signal your wait handle like this:

private void Button_Click(object sender, EventArgs e)
{
     myWaitHandle.Set(); // this signals the wait handle and your other thread will continue
}

Indeed, suspending a thread is bad practice since you very rarely know exactly what a thread is doing at the time. It is more predictable to have the thread run past a ManualResetEvent, calling WaitOne() each time. This will act as a gate - the controlling thread can call Reset() to shut the gate (pausing the thread, but safely), and Set() to open the gate (resuming the thread).

For example, you could call WaitOne at the start of each loop iteration (or once every n iterations if the loop is too tight).

You can try this also

private static AutoResetEvent _wait = new AutoResetEvent(false);

public Form1()
    {
        InitializeComponent();
    }

private void Form1_Load(object sender, EventArgs e)
    {
        Control.CheckForIllegalCrossThreadCalls = false;
        backgroundWorker1.RunWorkerAsync();
    }
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        Dosomething();
    }

private void Dosomething()
{
 //Your Loop
 for(int i =0;i<10;i++)
   {
    //Dosomething
    _wait._wait.WaitOne();//Pause the loop until the button was clicked.

   } 
}

private void btn1_Click(object sender, EventArgs e)
    {
        _wait.Set();
    }