Active Directory 用户组成员身份 GroupPrincipal

我正在尝试使用GroupPrincipal（的一部分System.DirectoryServices.AccountManagement名称空间）来填充字符串类型的列表，以便我可以检查用户是否是 Active Directory 组的成员。这是我迄今为止编写的编辑后的类：

public class ActiveDirectoryMembership
{
    private PrincipalContext context = new PrincipalContext(ContextType.Domain, Environment.UserDomainName);
    private List<string> GroupName {get;set;}

    public ActiveDirectoryMembership() 
    {
         //Code snipped - this part returns a list of users
         populateGroups();
    }

    private void populateGroups()
    {
        GroupPrincipal SearchGroup = GroupPrincipal.FindByIdentity(context, "Group Name");
        GroupName = new List<string>();
        foreach (UserPrincipal p in GroupName.GetMembers())
        {
           GroupName.add(p.SamAccountName);
        }
    }

那么，我哪里出错了？

提前致谢 ：）

对代码的这种修改有效（我进行了测试以确保）：

using System.DirectoryServices.AccountManagement;


    private static readonly string DomainName = "domaincontrollercomputer.domain.com";
    private static readonly string DomainContainer = "DC=DOMAIN,DC=COM";
    private static readonly string ADGroupName = "AD Group Name";
    private List<string> GroupName {get;set;}
      
    private void populateGroups()
    {
        using (var ctx = new PrincipalContext(ContextType.Domain, DomainName, DomainContainer))
        {
            using (var grp = GroupPrincipal.FindByIdentity(ctx, ADGroupName))
            {
                GroupName = new List<string>();
                foreach (var member in grp.GetMembers())
                {
                    GroupName.Add(member.SamAccountName);
                }
            }
        }
    }