The System.Web.Security.Membership class provides a Membership.GeneratePassword(int, int) method, which generates a password of a specified size with at least the specified number of non-alphabetic characters. The SqlMembershipProvider.GeneratePassword method of the System.Web.Security.SqlMembershipProvider calls the Membership.GeneratePassword(int, int) method of the System.Web.Security.Membership class to retrieve a random password that is at least 14 characters long. If the SqlMembershipProvider.MinRequiredPasswordLength property is greater than 14, the password returned will be the length specified in the SqlMembershipProvider.MinRequiredPasswordLength property.

You can specifically call the SqlMembershipProvider.GeneratePassword method by referencing the System.Web.Security.SqlMembershipProvider class directly from the Membership.Provider property of the System.Web.Security.Membership class.

The generated password only contains alphanumeric characters and the following punctuation marks: !@#$%^&*()_-+=[{]};:<>|./?. No hidden or non-printable control characters are included in the generated password.