Checking if a user exists in Active Directory using C# or VB.Net

You can use the .Net Wrapper to see if a user exists in Active Directory or not.

Programming Langauges Supported

ASP.NET, C#, VB.Net, Visual Studio 2010, Visual Sutdio 2008

Method: UserExists

Parameters:  (string) Username

Precondition

An instance of the LDAP manager must be instantiated for a valid ADDS server.

Functionality

The method is called passing the Username as a string. Three things can then occur:

1. If the username exists in Active Directory and the method returns true.
2. If the username does not exist in Active Directory the method returns false
3. An Exception will be thrown for other errors

Example

Where LdapConnection is an instance of LdapManager

public Boolean UserExists(String UserName)
        {
            try
            {
                return LdapConnection.UserExists(UserName);
            }
            catch (Exception)
            {
                throw;
            }
        }

Post Condition

It should be noted that there is no residual connection to the authenticated User Name, this method does not result in any "Login" context.