private void btnSignup_Click(object sender, RoutedEventArgs e)
 {
     if (txtUsername.Text.Trim() == String.Empty)
     {
         MessageBox.Show("请输入用户名!");
         pwbPassword.Password = null;
         pwbConfirm.Password  = null;
         return;
     }
     else if (pwbConfirm.Password.Trim() == String.Empty || pwbPassword.Password.Trim() == String.Empty)
     {
         MessageBox.Show("请输入密码!");
         pwbPassword.Password = null;
         pwbConfirm.Password  = null;
         return;
     }
     else if (pwbPassword.Password == pwbConfirm.Password)
     {
         Administrator administrator = new Administrator();
         administrator.Name     = txtUsername.Text.ToString();
         administrator.Password = pwbConfirm.Password;
         DataAccessLayer dataAccesslayer = new DataAccessLayer();
         dataAccesslayer.InsertAdministrator(administrator);
         noAdminAccount = false;
         this.Close();
         return;
     }
     else
     {
         MessageBox.Show("两次密码不一致!");
         pwbPassword.Password = null;
         pwbConfirm.Password  = null;
         return;
     }
 }
        private void btn_Signup_Click(object sender, RoutedEventArgs e)
        {
            DataAccessLayer dataAccesslayer = new DataAccessLayer();

            if (txt_Username.Text.Trim() == String.Empty)
            {
                SystemSounds.Beep.Play();
                MessageBox.Show("请输入用户名!");
                pwd_Password.Password = null;
                pwd_Confirm.Password  = null;
                return;
            }
            else if (dataAccesslayer.QueryAdministratorByName(txt_Username.Text).Count() > 0)
            {
                SystemSounds.Beep.Play();
                MessageBox.Show("已存在管理员:" + txt_Username + "!");
                return;
            }
            else if (pwd_Password.Password.Trim() == String.Empty || pwd_Confirm.Password.Trim() == String.Empty)
            {
                SystemSounds.Beep.Play();
                MessageBox.Show("请输入密码!");
                pwd_Password.Password = null;
                pwd_Confirm.Password  = null;
                return;
            }
            else if (pwd_Password.Password == pwd_Confirm.Password)
            {
                Administrator administrator = new Administrator();
                administrator.Name     = txt_Username.Text.ToString();
                administrator.Password = pwd_Confirm.Password;
                dataAccesslayer.InsertAdministrator(administrator);
                adminManagePage.FillDataGrid();
                this.Close();
                return;
            }
            else
            {
                SystemSounds.Beep.Play();
                MessageBox.Show("两次输入的密码不一致!");
                pwd_Password.Password = null;
                pwd_Confirm.Password  = null;
                return;
            }
        }