private void btnAdd_Click(object sender, EventArgs e)
{
Client myClient = new Client();
UseDB uDB = new UseDB();
myClient.Name = txtbName.Text;
myClient.Phone = Convert.ToInt32(txtbPhone.Text);
myClient.PassportSer = txtbPassSer.Text;
myClient.PassportNum = Convert.ToInt32(txtbPassNum.Text);
uDB.OpenConnection();
uDB.InsertClient(myClient);
uDB.CloseCon();
this.Hide();
}