private void btn_login_Click(object sender, EventArgs e)
 {
     if (ValidateInputs())
     {
         this.label_status.Text = "Connecting .....";
         SharePointOnlineManager manager = new SharePointOnlineManager(url);
         if (manager.ConnectToSharePoint(username, password, out string res))
         {
             this.Hide();
             form = new Form1(manager);
             form.ShowDialog();
             this.Close();
         }
         else
         {
             this.label_status.ForeColor = Color.Red;
             this.label_status.Text      = res;
         }
     }
 }
 public Form1(SharePointOnlineManager spManager)
 {
     this.spManager = spManager;
     InitializeComponent();
     this.richTextBox1.AppendText(result);
 }