主题：AD域用户验证

private void btnLogin_Click(object sender, EventArgs e)
{
    if( txtUsername.Text.Length == 0 || txtPassword.Text.Length == 0 ) {
        MessageBox.Show("用户名或者密码不能为空。", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Warning);
        return;
    }

    string ldapPath = "LDAP://" + GetDomainName();
    string domainAndUsername = Environment.UserDomainName + "\\" + txtUsername.Text;
    DirectoryEntry entry = new DirectoryEntry(ldapPath, domainAndUsername, txtPassword.Text);

    DirectorySearcher search = new DirectorySearcher(entry);

    try {
        SearchResult result = search.FindOne();

        MessageBox.Show("登录成功。", this.Text, MessageBoxButtons.OK, MessageBoxIcon.Information);
    }
    catch( Exception ex ) {
        // 如果用户名或者密码不正确，也会抛出异常。
        MessageBox.Show(ex.Message, this.Text, MessageBoxButtons.OK, MessageBoxIcon.Stop);
    }
}

请问这个在Foxtable中怎么写啊？ 用于域验证