void okButton_Click(object sender, EventArgs e) { try { this.DialogResult = DialogResult.None; if (userNamTextBox.Text.Length == 0) { MessageBox.Show(this, "Enter a user name.", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); return; } else if (passwordTextBox.Text.Length == 0) { MessageBox.Show(this, "Enter a user password.", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); return; } else if (!UserAccessManager.AuthenticateUser(userNamTextBox.Text, UserAccessManager.GetSecureString(passwordTextBox.Text))) { MessageBox.Show(this, "Invalid user name or password.", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); return; } else { DialogResult = DialogResult.OK; } } catch (Exception exception) { MessageBox.Show(this, exception.Message, this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); } finally { passwordTextBox.Text = string.Empty; } }