首先我们来了解一下什么是Active Directory。不用我描述，看以下网址，或在.net自带帮助文档里根据Active Directory关键字一搜，就什么都明白了。

接下来，我们来看看权限。你可以通过“网上邻居--整个网络--Directory--demain(你的域名)”你就可以看到所有关于域下的信息，粗一看就知道是怎么回事了。
需要告诉大家的：所有组织单位下的用户都在Users(容器)--Demain Users(组)中
用代码进行访问时，如果你是域管理员用户，则可以做任何操作，否则，只能查询用户属性。

private void SearchUser()
{
string domainName = "Domain";
string groupName = "Domain Users";
string dirmemName="";
//在Domain Users域用户里取得每个用户名
System.DirectoryServices.DirectoryEntry group = new System.DirectoryServices.DirectoryEntry("WinNT://" + domainName + "/" + groupName + ",group");
foreach(Object member in (IEnumerable)group.Invoke("Members"))
{
//根据很个用户生成如："LDAP://OU=套装软体课,OU=系统开发部,OU=资讯服务处,OU=营运支援中心,OU=XX公司,DC=Domain,DC=com,DC=cn"
System.DirectoryServices.DirectoryEntry dirmem = new System.DirectoryServices.DirectoryEntry(member);
dirmemName=dirmem.Name;
string DomainName="Domain";
string FilterStr = "(sAMAccountname="+dirmemName+")";
System.DirectoryServices.DirectorySearcher FindMe = new System.DirectoryServices.DirectorySearcher(DomainName);
FindMe.Filter = FilterStr;
System.DirectoryServices.SearchResult FindRes = FindMe.FindOne();
System.DirectoryServices.DirectoryEntry MyUser = FindRes.GetDirectoryEntry();
string OUPath=MyUser.Parent.Path;
//找到该用户所在的LDAP:后，由域管理员登录，并取得该用户的所在属性。
string strFieldsValue="",strFields="";
System.DirectoryServices.DirectoryEntry myds=new System.DirectoryServices.DirectoryEntry(OUPath,"域管理员名","域管理员密码");
foreach(System.DirectoryServices.DirectoryEntry tempEntry in myds.Children)
{
if(tempEntry.SchemaClassName.ToString() == "user" && tempEntry.Properties["sAMAccountName"].Value.ToString().ToLower()==dirmemName)
{
foreach (string propertyName in tempEntry.Properties.PropertyNames )
{
string oneNode = propertyName + ": " +
entry.Properties[propertyName][0].ToString();
this.Textbox1.Text=oneNode;
}
}

-------------------------------------------

public void AddUser(string strPath,string Username,string ChineseName)//strPath 增加用户至哪个组织单位如"LDAP://OU=XX公司,DC=Domain,DC=com"帐号、中文名{
try
{
string RootDSE;
//System.DirectoryServices.DirectorySearcher DSESearcher= new System.DirectoryServices.DirectorySearcher();
//RootDSE=DSESearcher.SearchRoot.Path;
//RootDSE="LDAP://DC=Domain,DC=com";
//RootDSE=RootDSE.Insert(7,"CN=Users,");
System.DirectoryServices.DirectoryEntry myDE = new System.DirectoryServices.DirectoryEntry(strPath);
System.DirectoryServices.DirectoryEntries myEntries = myDE.Children;
// Create a new entry 'Sample' in the container.
string strname="CN="+ChineseName;
System.DirectoryServices.DirectoryEntry myDirectoryEntry = myEntries.Add(strname, "user");

//MessageBox.Show(myDirectoryEntry.SchemaClassName.ToString());
myDirectoryEntry.Properties["userPrincipalName"].Value=Username;
myDirectoryEntry.Properties["name"].Value=ChineseName;
myDirectoryEntry.Properties["samAccountName"].Value=Username;
myDirectoryEntry.Properties["userAccountControl"].Value =66048; //590336;
myDirectoryEntry.CommitChanges();
}

----------------------------------------------

private void addOU(string strPath,string OUName)//增加组织到strPath组织单位下，组织名称
{
try
{
//String RootDSE;
//System.DirectoryServices.DirectorySearcher DSESearcher= new System.DirectoryServices.DirectorySearcher();
//RootDSE=DSESearcher.SearchRoot.Path;
//RootDSE="LDAP://OU=百意时尚广场,DC=Domain,DC=com";

System.DirectoryServices.DirectoryEntry myDE = new System.DirectoryServices.DirectoryEntry(strPath);
System.DirectoryServices.DirectoryEntries myEntries = myDE.Children;
string name="OU="+OUName;
System.DirectoryServices.DirectoryEntry myDirectoryEntry = myEntries.Add(name,"organizationalUnit");

myDirectoryEntry.Properties["name"].Value=OUName;
myDirectoryEntry.Properties["instanceType"].Value=4;
myDirectoryEntry.Properties["distinguishedName"].Value="OU="+OUName+",DC=Domain,DC=COM)";
myDirectoryEntry.Properties["objectCategory"].Value="CN=Organizational-Unit,CN=Schema,CN=Configuration,DC=sedep,DC=COM";
myDirectoryEntry.Properties["ou"].Value=OUName;
myDirectoryEntry.Properties["postalCode"].Value="777";

myDirectoryEntry.CommitChanges();
//UserMoveto("LDAP://OU="+OUName+",DC=sedep,DC=com",strPath);
}
catch(Exception RaiseErr)
{
MessageBox.Show (RaiseErr.Message);
}
}

---------------------------------------------

private void ModifyUser()
{
try
{
string DomainName="Domain";
string FilterStr = "(sAMAccountname=karlluo)";
System.DirectoryServices.DirectorySearcher FindMe = new System.DirectoryServices.DirectorySearcher(DomainName);
FindMe.Filter = FilterStr;
System.DirectoryServices.SearchResult FindRes = FindMe.FindOne();
string tt=FindRes.Path;
System.DirectoryServices.DirectoryEntry MyUser = FindRes.GetDirectoryEntry();
string OUPath=MyUser.Parent.Path;

DirectoryEntry myds=new DirectoryEntry(OUPath,"域管理员名","域管理员密码");

foreach(System.DirectoryServices.DirectoryEntry tempEntry in myds.Children)
{
if(tempEntry.SchemaClassName.ToString() == "user")
{
if(tempEntry.Properties["sAMAccountName"].Value.ToString().ToLower()=="karlluo")
{
tempEntry.UsePropertyCache=true;
tempEntry.Properties["st"].Value="yyyyyyyyyyyyyyyy";
//newEntry.Properties["userPrincipalName"].Value="userID";
tempEntry.CommitChanges();
}
}
}
}
catch(Exception RaiseErr)
{
MessageBox.Show (RaiseErr.Message);
}

}

来源:网络