Error while passing argument
<p>I have a UserBll class which has  following method </p>

<pre><code>public string GetaspnetUserIdByUserName(string name )
{
    string _lsttUserId = (from aspnet in db.aspnet_Users
                            where aspnet.UserName.Equals(name)
                            select aspnet.UserId
                         ).ToString();
    return _lsttUserId;
}
</code></pre>

<p>I create an instance of Usertable having UserId and UserName field and I am using following code</p>

<pre><code>UserBLL bll = new UserBL
UserTable uTable = new UserTable();
uTable.UserId = bll.GetaspnetUserIdByUserName(Membership.GetUser(model.UserName));
</code></pre>

<p>in above code I get following error:</p>

<blockquote>
  <p>GetaspnetUserIdByUserName has some invalid argument </p>
</blockquote>

<p>Can somebody please tell me what wrong I am doing </p>
