If you want to authenticate user with active directory and the show the data on web page.
public bool ValidateCredentials(string username, string password)
{
string adServer= "AD Server Name";
StringBuilder sb = new StringBuilder();
DirectoryEntry entry = new DirectoryEntry(adServer);//connect to server
DirectorySearcher search = new DirectorySearcher(entry);
string domain = System.Configuration.ConfigurationSettings.AppSettings["Domain"];
using (PrincipalContext pc = new PrincipalContext(ContextType.Domain, domain))
{
return pc.ValidateCredentials(username, password);
}
}