这里是我完整的认证解决方案，供您参考。

首先，添加以下四个引用

 using System.DirectoryServices;
 using System.DirectoryServices.Protocols;
 using System.DirectoryServices.AccountManagement;
 using System.Net; 

private void AuthUser() { 


      try{
            string Uid = "USER_NAME";
            string Pass = "PASSWORD";
            if (Uid == "")
            {
                MessageBox.Show("Username cannot be null");
            }
            else if (Pass == "")
            {
                MessageBox.Show("Password cannot be null");
            }
            else
            {
                LdapConnection connection = new LdapConnection("YOUR DOMAIN");
                NetworkCredential credential = new NetworkCredential(Uid, Pass);
                connection.Credential = credential;
                connection.Bind();

                // after authenticate Loading user details to data table
                PrincipalContext ctx = new PrincipalContext(ContextType.Domain);
                UserPrincipal user = UserPrincipal.FindByIdentity(ctx, Uid);
                DirectoryEntry up_User = (DirectoryEntry)user.GetUnderlyingObject();
                DirectorySearcher deSearch = new DirectorySearcher(up_User);
                SearchResultCollection results = deSearch.FindAll();
                ResultPropertyCollection rpc = results[0].Properties;
                DataTable dt = new DataTable();
                DataRow toInsert = dt.NewRow();
                dt.Rows.InsertAt(toInsert, 0);

                foreach (string rp in rpc.PropertyNames)
                {
                    if (rpc[rp][0].ToString() != "System.Byte[]")
                    {
                        dt.Columns.Add(rp.ToString(), typeof(System.String));

                        foreach (DataRow row in dt.Rows)
                        {
                            row[rp.ToString()] = rpc[rp][0].ToString();
                        }

                    }  
                }
             //You can load data to grid view and see for reference only
                 dataGridView1.DataSource = dt;


            }
        } //Error Handling part
        catch (LdapException lexc)
        {
            String error = lexc.ServerErrorMessage;
            string pp = error.Substring(76, 4);
            string ppp = pp.Trim();

            if ("52e" == ppp)
            {
                MessageBox.Show("Invalid Username or password, contact ADA Team");
            }
            if ("775​" == ppp)
            {
                MessageBox.Show("User account locked, contact ADA Team");
            }
            if ("525​" == ppp)
            {
                MessageBox.Show("User not found, contact ADA Team");
            }
            if ("530" == ppp)
            {
                MessageBox.Show("Not permitted to logon at this time, contact ADA Team");
            }
            if ("531" == ppp)
            {
                MessageBox.Show("Not permitted to logon at this workstation, contact ADA Team");
            }
            if ("532" == ppp)
            {
                MessageBox.Show("Password expired, contact ADA Team");
            }
            if ("533​" == ppp)
            {
                MessageBox.Show("Account disabled, contact ADA Team");
            }
            if ("533​" == ppp)
            {
                MessageBox.Show("Account disabled, contact ADA Team");
            }



        } //common error handling
        catch (Exception exc)
        {
            MessageBox.Show("Invalid Username or password, contact ADA Team");

        }

        finally {
            tbUID.Text = "";
            tbPass.Text = "";

        }
    }

完整的. net解决方案是使用来自系统的类。DirectoryServices名称空间。它们允许直接查询AD服务器。下面是一个可以做到这一点的小样本:

using (DirectoryEntry entry = new DirectoryEntry())
{
    entry.Username = "here goes the username you want to validate";
    entry.Password = "here goes the password";

    DirectorySearcher searcher = new DirectorySearcher(entry);

    searcher.Filter = "(objectclass=user)";

    try
    {
        searcher.FindOne();
    }
    catch (COMException ex)
    {
        if (ex.ErrorCode == -2147023570)
        {
            // Login or password is incorrect
        }
    }
}

// FindOne() didn't throw, the credentials are correct

这段代码使用提供的凭据直接连接到AD服务器。如果凭证无效，则search . findone()将抛出异常。ErrorCode是一个对应于“无效的用户名/密码”COM错误。

您不需要以AD用户的身份运行代码。事实上，我成功地使用它在AD服务器上查询信息，从域外的客户端!

我们在内部网做这些

你必须使用System.DirectoryServices;

下面是代码的核心部分

using (DirectoryEntry adsEntry = new DirectoryEntry(path, strAccountId, strPassword))
{
    using (DirectorySearcher adsSearcher = new DirectorySearcher(adsEntry))
    {
        //adsSearcher.Filter = "(&(objectClass=user)(objectCategory=person))";
        adsSearcher.Filter = "(sAMAccountName=" + strAccountId + ")";

        try
        {
            SearchResult adsSearchResult = adsSearcher.FindOne();
            bSucceeded = true;

            strAuthenticatedBy = "Active Directory";
            strError = "User has been authenticated by Active Directory.";
        }
        catch (Exception ex)
        {
            // Failed to authenticate. Most likely it is caused by unknown user
            // id or bad strPassword.
            strError = ex.Message;
        }
        finally
        {
            adsEntry.Close();
        }
    }
}

对我来说，这两个下面的工作，确保你的域名是LDAP://在开始

//"LDAP://" + domainName
private void btnValidate_Click(object sender, RoutedEventArgs e)
{
    try
    {
        DirectoryEntry de = new DirectoryEntry(txtDomainName.Text, txtUsername.Text, txtPassword.Text);
        DirectorySearcher dsearch = new DirectorySearcher(de);
        SearchResult results = null;

        results = dsearch.FindOne();

        MessageBox.Show("Validation Success.");
    }
    catch (LdapException ex)
    {
        MessageBox.Show($"Validation Failure. {ex.GetBaseException().Message}");
    }
    catch (Exception ex)
    {
        MessageBox.Show($"Validation Failure. {ex.GetBaseException().Message}");
    }
}

private void btnValidate2_Click(object sender, RoutedEventArgs e)
{
    try
    {
        LdapConnection lcon = new LdapConnection(new LdapDirectoryIdentifier((string)null, false, false));
        NetworkCredential nc = new NetworkCredential(txtUsername.Text,
                               txtPassword.Text, txtDomainName.Text);
        lcon.Credential = nc;
        lcon.AuthType = AuthType.Negotiate;
        lcon.Bind(nc);

        MessageBox.Show("Validation Success.");
    }
    catch (LdapException ex)
    {
        MessageBox.Show($"Validation Failure. {ex.GetBaseException().Message}");
    }
    catch (Exception ex)
    {
        MessageBox.Show($"Validation Failure. {ex.GetBaseException().Message}");
    }
}

试试这段代码 (注意:报告不能在windows server 2000上工作)

#region NTLogonUser
#region Direct OS LogonUser Code
[DllImport( "advapi32.dll")]
private static extern bool LogonUser(String lpszUsername, 
    String lpszDomain, String lpszPassword, int dwLogonType, 
    int dwLogonProvider, out int phToken);

[DllImport("Kernel32.dll")]
private static extern int GetLastError();

public static bool LogOnXP(String sDomain, String sUser, String sPassword)
{
   int token1, ret;
   int attmpts = 0;

   bool LoggedOn = false;

   while (!LoggedOn && attmpts < 2)
   {
      LoggedOn= LogonUser(sUser, sDomain, sPassword, 3, 0, out token1);
      if (LoggedOn) return (true);
      else
      {
         switch (ret = GetLastError())
         {
            case (126): ; 
               if (attmpts++ > 2)
                  throw new LogonException(
                      "Specified module could not be found. error code: " + 
                      ret.ToString());
               break;

            case (1314): 
               throw new LogonException(
                  "Specified module could not be found. error code: " + 
                      ret.ToString());

            case (1326): 
               // edited out based on comment
               //  throw new LogonException(
               //   "Unknown user name or bad password.");
            return false;

            default: 
               throw new LogonException(
                  "Unexpected Logon Failure. Contact Administrator");
              }
          }
       }
   return(false);
}
#endregion Direct Logon Code
#endregion NTLogonUser

除非你需要为“LogonException”创建自己的自定义异常

我使用这个过程作为DLL登录到我们开发的其他应用程序… (我们目前正在使用OpenEdge Progress)

public static string AzureLogin(string user, string password) {

    string status;

    try {
        new DirectorySearcher(new DirectoryEntry("LDAP://yourdomain.com", user, password) {
            AuthenticationType = AuthenticationTypes.Secure,
            Username = user,
            Password = password
        })  {
            Filter = "(objectclass=user)"
        }.FindOne().Properties["displayname"][0].ToString();

        status = $"SUCCESS - User {user} has logged in.";

    } catch(System.Exception e) {
        status = $"ERROR - While logging in: {e}";
    }

    return status;
}