How to show custom error in asp.net razor view

Question

I would like to display "No profile found" message, if the UserId doesn't exist in the database. How can i implement it. The code below does not work.

          UserId = Request.QueryString["UserId"];
           var db = Database.Open("mystring");
           var selectCommand = "SELECT * FROM UserProfile WHERE UserId = @0";
           var row = db.QuerySingle(selectCommand, UserId);

             if (row != null)
            {
                Email = row.Email;
                fullname = row.fullname;
                about = row.about;
             }else{
                 ModelState.AddFormError("No Profile Found.");

             }

Answer 1

Try like this:

@{
    var userId = Request.QueryString["UserId"];
    var db = Database.Open("mystring");
    var selectCommand = "SELECT * FROM UserProfile WHERE UserId = @0";
    var row = db.QuerySingle(selectCommand, UserId);
}

@if (row != null) {
    <div>
        Email: @row.Email
    </div>
    <div>
        Fullname: @row.fullname
    </div>
    <div>
        About: @row.about
    </div>
} else {
    <div>No Profile Found.</div>
}