如何查询用户是否存在-从Combobox传递域名返回默认域名

1. 获取所有可用的域

using System.DirectoryServices.ActiveDirectory;

var domainList = new List<string>();

Forest currentForest = Forest.GetCurrentForest();
foreach (Domain domain in currentForest.Domains)
{
    domainList.Add(domain.Name);
}

// 将域名添加到Combobox中
comboBox1.DataSource = domainList;

2. 查询用户是否存在

string userName = "testuser";
string domainName = comboBox1.Text;

// LDAP路径
string ldapPath = string.Format("LDAP://{0}", domainName);

// 绑定LDAP路径
DirectoryEntry entry = new DirectoryEntry(ldapPath);
entry.AuthenticationType = AuthenticationTypes.Secure;

// 设置查询参数
DirectorySearcher searcher = new DirectorySearcher(entry);
searcher.Filter = string.Format("(&(objectClass=user)(sAMAccountName={0}))", userName);

try
{
    SearchResult result = searcher.FindOne();
    if (result != null)
    {
        // 用户存在
        MessageBox.Show("用户存在");
    }
    else
    {
        // 用户不存在
        MessageBox.Show("用户不存在");
    }
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}