列出所有使用目录服务的本地用户

Question

The following method I created seem does not work. An error always happens on foreach loop.

NotSupportedException was unhandled...The provider does not support searching and cannot search WinNT://WIN7,computer.

I'm querying the local machine

 private static void listUser(string computer)
 {
        using (DirectoryEntry d= new DirectoryEntry("WinNT://" + 
                     Environment.MachineName + ",computer"))
        {
           DirectorySearcher ds = new DirectorySearcher(d);
            ds.Filter = ("objectClass=user");
            foreach (SearchResult s in ds.FindAll())
            {

              //display name of each user

            }
        }
    }

Answer 1

You cannot use a DirectorySearcher with the WinNT provider . From the documentation:

Use a DirectorySearcher object to search and perform queries against an Active Directory Domain Services hierarchy using Lightweight Directory Access Protocol (LDAP). LDAP is the only system-supplied Active Directory Service Interfaces (ADSI) provider that supports directory searching.

Instead, use the DirectoryEntry.Children property to access all child objects of your Computer object , then use the SchemaClassName property to find the children that are User objects .

With LINQ:

string path = string.Format("WinNT://{0},computer", Environment.MachineName);

using (DirectoryEntry computerEntry = new DirectoryEntry(path))
{
    IEnumerable<string> userNames = computerEntry.Children
        .Cast<DirectoryEntry>()
        .Where(childEntry => childEntry.SchemaClassName == "User")
        .Select(userEntry => userEntry.Name);

    foreach (string name in userNames)
        Console.WriteLine(name);
}       

Without LINQ:

string path = string.Format("WinNT://{0},computer", Environment.MachineName);

using (DirectoryEntry computerEntry = new DirectoryEntry(path))
    foreach (DirectoryEntry childEntry in computerEntry.Children)
        if (childEntry.SchemaClassName == "User")
            Console.WriteLine(childEntry.Name);

Answer 2

The following are a few different ways to get your local computer name:

string name = Environment.MachineName;
string name = System.Net.Dns.GetHostName();
string name = System.Windows.Forms.SystemInformation.ComputerName;
string name = System.Environment.GetEnvironmentVariable(“COMPUTERNAME”);

The next one is a way to get the current user name:

string name = System.Windows.Forms.SystemInformation.UserName;