My winform app have two tab and multi thread, one is main tab and other is log tab. I only use log tab to show logs in a datagridview control. Exception is random occurred when click to log tab (Not click to row or colunm), i have try but can not find anyway to fix it. This is the error log:

Message : Object reference not set to an instance of an object.
Source : System.Windows.Forms
TargetSite : System.Windows.Forms.DataGridViewElementStates GetRowState(Int32)
StackTrace :    at System.Windows.Forms.DataGridViewRowCollection.GetRowState(Int32 rowIndex)
   at System.Windows.Forms.DataGridView.ComputeHeightOfFittingTrailingScrollingRows(Int32 totalVisibleFrozenHeight)
   at System.Windows.Forms.DataGridView.GetOutOfBoundCorrectedHitTestInfo(HitTestInfo& hti, Int32& mouseX, Int32& mouseY, Int32& xOffset, Int32& yOffset)
   at System.Windows.Forms.DataGridView.OnMouseMove(MouseEventArgs e)
   at System.Windows.Forms.Control.WmMouseMove(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.DataGridView.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Message : Object reference not set to an instance of an object.
Source : System.Windows.Forms
TargetSite : Void ClearInternal(Boolean)
StackTrace :    at System.Windows.Forms.DataGridViewRowCollection.ClearInternal(Boolean recreateNewRow)
   at System.Windows.Forms.DataGridView.OnClearingColumns()
   at System.Windows.Forms.DataGridViewColumnCollection.Clear()
   at System.Windows.Forms.DataGridView.Dispose(Boolean disposing)
   at System.ComponentModel.Component.Dispose()
   at System.Windows.Forms.Control.Dispose(Boolean disposing)
   at System.ComponentModel.Component.Dispose()
   at System.Windows.Forms.Control.Dispose(Boolean disposing)
   at System.Windows.Forms.TabControl.Dispose(Boolean disposing)
   at System.ComponentModel.Component.Dispose()
   at System.Windows.Forms.Control.Dispose(Boolean disposing)
   at System.Windows.Forms.Form.Dispose(Boolean disposing)

Update status code:

    private void updateMessage(int index, string message)
    {
        try
        {
            this.dgForums.Rows[index].Cells["ColStatus"].Value = message;

            System.Windows.Forms.Application.DoEvents();
        }
        catch
        {
        }
    }