Hi,

I have a form which will be used to log tech support calls. What happens is a user enters in a username and I want to return a firstname, lastname, and email address.

I have this working if it gets the currently logged on user via Request.LogonUserIdentity.User and it returns the name and email address but not for the user calling in.

I included a sample of what I'm trying to do but of course you can't go directlly from username to sid as shown in line one.

1    Dim user As System.Security.Principal.SecurityIdentifier = txtUserName.Text.Trim 'error here .
2    
3    Dim dir As New DirectoryEntry("LDAP://<SID=" + SidToHex(user) + ">")
4    dir = New DirectoryEntry("LDAP://" + DirectCast(dir.Properties("distinguishedName")(0), String), Nothing, Nothing, AuthenticationTypes.Secure Or AuthenticationTypes.ReadonlyServer)
5    
6    FirstName = dir.Properties("givenName")(0).ToString
7    LastName = dir.Properties("sn")(0).ToString
8    EmailAddress = dir.Properties("mail")(0).ToString
9    

If you have the username of the calling user, then you should use DirectorySearcher with a filter including the sAMAccountName. There's no shortcut to jump from username to SID as you have already discovered. 

DirectoryEntry root = new DirectoryEntry("DC=somedomain,DC=com");
DirectoryEntry user = null;
using (DirectorySearcher search = new DirectorySearcher(root))
{
	search.SearchScope = SearchScope.Subtree;
	search.Filter = "(&(objectClass=user)(sAMAccountName=" + txtUserName.Text.Trim() + "))";
	search.PropertiesToLoad.AddRange(new string[] { "givenName", "sn", "mail" });
	SearchResultCollection searchResultColl = search.FindAll();
	if (searchResultColl.Count == 1)
	{
		user = searchResultColl[0].GetDirectoryEntry();
	}
	else
	{
		// User not found
	}
}
FirstName = user.Properties["givenName"][0].Value;
...

I just realized you're probably working in VB.net. I wrote this code in C#, but I think you should be able to get the point with this. Good luck!