private void buttonLogin_Click(object sender, EventArgs e) { if (textBoxUsername.Text.Equals("") || textBoxPassword.Text.Equals("")) { MessageBox.Show("用户名或密码为空"); return; } try { SupplierInfo.supplier = SupplierDataAccess.LoginSupplier(textBoxUsername.Text, textBoxPassword.Text); MainForm mainForm = MainForm.CreateForm(); Hide(); mainForm.ShowDialog(); Show(); } catch { MessageBox.Show("登录失败"); } }