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!

可能最简单的方法是PInvoke LogonUser Win32 api。

http://www.pinvoke.net/default.aspx/advapi32/LogonUser.html

MSDN参考在这里…

http://msdn.microsoft.com/en-us/library/aa378184.aspx

绝对要使用登录类型

LOGON32_LOGON_NETWORK (3)

这只创建了一个轻量级的令牌-完美的认证检查。(其他类型可用于构建交互式会话等)

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 = "";

        }
    }

另一个.NET调用用于快速验证LDAP凭据:

using System.DirectoryServices;

using(var DE = new DirectoryEntry(path, username, password)
{
    try
    {
        DE.RefreshCache(); // This will force credentials validation
    }
    catch (COMException ex)
    {
        // Validation failed - handle how you want
    }
}

如果你使用的是。net 3.5或更新版本，你可以使用System.DirectoryServices.AccountManagement命名空间轻松验证你的凭证:

// create a "principal context" - e.g. your domain (could be machine, too)
using(PrincipalContext pc = new PrincipalContext(ContextType.Domain, "YOURDOMAIN"))
{
    // validate the credentials
    bool isValid = pc.ValidateCredentials("myuser", "mypassword");
}

它简单，可靠，在你的端是100%的c#托管代码——你还能要求什么呢?: -)

在这里阅读所有内容:

在.NET Framework 3.5中管理目录安全主体 System.DirectoryServices.AccountManagement上的MSDN文档

更新:

正如在另一个SO问题(及其答案)中概述的那样，对于用户的旧密码，这个调用可能会返回True。只是要注意这种行为，如果发生这种情况不要太惊讶:-)(感谢@MikeGledhill指出这一点!)

Windows身份验证失败的原因有很多:用户名或密码不正确、帐户被锁定、密码过期等等。为了区分这些错误，通过P/Invoke调用LogonUser API函数，如果函数返回false，检查错误代码:

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;

using Microsoft.Win32.SafeHandles;

public static class Win32Authentication
{
    private class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
        private SafeTokenHandle() // called by P/Invoke
            : base(true)
        {
        }

        protected override bool ReleaseHandle()
        {
            return CloseHandle(this.handle);
        }
    }

    private enum LogonType : uint
    {
        Network = 3, // LOGON32_LOGON_NETWORK
    }

    private enum LogonProvider : uint
    {
        WinNT50 = 3, // LOGON32_PROVIDER_WINNT50
    }

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool CloseHandle(IntPtr handle);

    [DllImport("advapi32.dll", SetLastError = true)]
    private static extern bool LogonUser(
        string userName, string domain, string password,
        LogonType logonType, LogonProvider logonProvider,
        out SafeTokenHandle token);

    public static void AuthenticateUser(string userName, string password)
    {
        string domain = null;
        string[] parts = userName.Split('\\');
        if (parts.Length == 2)
        {
            domain = parts[0];
            userName = parts[1];
        }

        SafeTokenHandle token;
        if (LogonUser(userName, domain, password, LogonType.Network, LogonProvider.WinNT50, out token))
            token.Dispose();
        else
            throw new Win32Exception(); // calls Marshal.GetLastWin32Error()
    }
}

示例用法:

try
{
    Win32Authentication.AuthenticateUser("EXAMPLE\\user", "P@ssw0rd");
    // Or: Win32Authentication.AuthenticateUser("user@example.com", "P@ssw0rd");
}
catch (Win32Exception ex)
{
    switch (ex.NativeErrorCode)
    {
        case 1326: // ERROR_LOGON_FAILURE (incorrect user name or password)
            // ...
        case 1327: // ERROR_ACCOUNT_RESTRICTION
            // ...
        case 1330: // ERROR_PASSWORD_EXPIRED
            // ...
        case 1331: // ERROR_ACCOUNT_DISABLED
            // ...
        case 1907: // ERROR_PASSWORD_MUST_CHANGE
            // ...
        case 1909: // ERROR_ACCOUNT_LOCKED_OUT
            // ...
        default: // Other
            break;
    }
}

注意:LogonUser需要与您验证的域建立信任关系。