Faster way to find out if a user exists on a system?

Question

I have an application that checks to see if a user exists (if not create it) every time it starts. This is done as follows:

bool bUserExists = false;
Directo         


        

Answer 1

.NET 3.5 supports new AD querying classes under the System.DirectoryServices.AccountManagement namespace.

To make use of it, you'll need to add "System.DirectoryServices.AccountManagement" as a reference AND add the using statement.

using System.DirectoryServices.AccountManagement;


using (PrincipalContext pc = new PrincipalContext(ContextType.Machine))
{
    UserPrincipal up = UserPrincipal.FindByIdentity(
        pc,
        IdentityType.SamAccountName,
        "UserName");

    bool UserExists = (up != null);
}

< .NET 3.5

For versions of .NET prior to 3.5, here is a clean example I found on dotnet-snippets

DirectoryEntry dirEntryLocalMachine =
    new DirectoryEntry("WinNT://" + Environment.MachineName + ",computer");

bool UserExists =
    dirEntryLocalMachine.Children.Find(userIdentity, "user") != null;