PasswordReset() throws exception - passwordAnswer? - asp.net

Question

I have an app that I'm trying to implement the following, but can't seem to figure out how:
User signs up, but the system creates its own temporary password for them
Admin approves user and as part of that approval, the user gets sent a temporary username/password.
The problem is that I can't set the MembershipProvider to enable password retrieval as that seems to disable certficate authentication. I do have passwordReset enabled, but when I try to use it in step 2 (trying to create a new password so I can have it in plaintext to email it to the user), it throws an error:
General Error: System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.ArgumentNullException: Value cannot be null.
Parameter name: passwordAnswer
Is there any way around this?
Here's a code snippet of the relevant code:
MembershipUser mu = Membership.GetUser(Session["UserId"], false);
string password = mu.ResetPassword();

Answer 1

The password is null because nothing got entered. In your code, just use an if:
if (passwordAnswer==null){
//do stuff here
}
While you can write anything there, I recommend, maybe:
if (passwordAnswer==null){
passwordAnswer=" ";//just a space
}
If you want it to be a generated password, research on generating random alphanumeric strings.

Answer 2

I was able to circumvent this issue by adding requiresQuestionAndAnswer="false" to the membership provider in my web.config:
<membership defaultProvider="DefaultMembershipProvider">
<providers>
<add name="DefaultMembershipProvider"
type="System.Web.Security.SqlMembershipProvider"
requiresUniqueEmail="true"
connectionStringName="DB"
applicationName="Acme"
maxInvalidPasswordAttempts="3"
requiresQuestionAndAnswer="false"
enablePasswordReset="true"
minRequiredPasswordLength="15"
minRequiredNonalphanumericCharacters="1"
passwordAttemptWindow="3"
passwordFormat="Hashed" />
</providers>
</membership>