ScrollBars of DataGridview will be Crash when the height of all rows exceed the vision height of DataGridview

Question

As the title say,

DataGridview.ScrollBars = Vertical;

Assume the vision of DataGridview can contain 4 rows, if the row comes to 6, it has a Vertical ScrollBar. But if click the ScrollBar, the program will crash. If we set the DataGridview.ScrollBars = None, no problem will happen.

public partial class visitorLeave : Form
{
    public visitorLeave()
    {
        InitializeComponent();
    }
    bool isWorkerStopped = false;
    bool clickstart = false;
    ManageEmployee me = null;

    Thread tr1;

    private void visitorLeave_Load(object sender, EventArgs e)
    {
        me = new ManageEmployee(10);
        dataGridView1.AutoGenerateColumns = false;
        dataGridView1.DataSource = me.DataSource;
        tr1 = new Thread(new ThreadStart(Add));
        tr1.IsBackground = true;
        tr1.Start();
    }

    void Add()
    {
        while (!isWorkerStopped)
        {
            if (clickstart)
            {
                me.AddEmployee(new EmployeeData("new" + DateTime.Now.Ticks.ToString(), "0", "0", "0", "0", "0", null));
                dataGridView1.DataSource = me.DataSource;
                dataGridView1.UpdateRowHeightInfo(0, true);
                clickstart = false;
            }
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        clickstart = !clickstart;
    }
}

Answer 1

It is one of the leaks in Windows Forms' debugging logic that tries to detect you using controls in a thread-unsafe manner. It cannot see you assigning the DataSource property in a thread other than the UI thread.

Use BackgroundWorker to implement your threaded logic. And use its RunworkerCompleted event handler to set the grid's DataSource property. Or use Control.Invoke if you prefer to keep your existing threading code.