How to get a username in Active Directory from a display name in C#?

Question

I want to be able to obtain the userid of a user in Active Directory using the display name of that user. The display name is obtained from a database, and has been stored durin

Answer 1

I believe you can do it much more easily than with David's answer by using the built-in functionality of the System.DirectoryServices.AccountManagement (S.DS.AM) namespace.

Basically, you can define a domain context and easily find users and/or groups in AD:

using System.DirectoryServices.AccountManagement;

private string GetUserIdFromDisplayName(string displayName)
{
    // set up domain context
    using(PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
    {
        // find user by display name
        UserPrincipal user = UserPrincipal.FindByIdentity(ctx, displayName);

        // 
        if (user != null)
        {
             return user.SamAccountName;
             // or maybe you need user.UserPrincipalName;
        }
        else
        {
             return string.Empty;
        }
    }
}

I don't see any need to go to the underlying DirectoryEntry object, really - unless none of the properties of the UserPrincipal really are what you're looking for.

PS: if the search by display name shouldn't work (I don't have an AD at hand to test it right now) - you can always also use the PrincipalSearcher to find your user:

using System.DirectoryServices.AccountManagement;

private string GetUserIdFromDisplayName(string displayName)
{
    // set up domain context
    using(PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
    {
        // define a "query-by-example" principal - here, we search for a UserPrincipal 
        // and with the display name passed in
        UserPrincipal qbeUser = new UserPrincipal(ctx);
        qbeUser.DisplayName = displayName;

        // create your principal searcher passing in the QBE principal    
        PrincipalSearcher srch = new PrincipalSearcher(qbeUser);

        // find match - if exists
        UserPrincipal user = srch.FindOne() as UserPrincipal;

        if (user != null)
        {
             return user.SamAccountName;
             // or maybe you need user.UserPrincipalName;
        }
        else
        {
             return string.Empty;
        }
    }
}