Question

I would like to add the result of a LINQ 2 SQL query to a label or textbox.
I use a class “CustomerClass” as a datalayer. In here I have a method with a LINQ query.
This result needs to be returned to the code behind file and added to a label or textbox.

Method in Class:

public static object SelectCustomerByUser(string user)
{
    var query = (from p in dc.Customers
                 where p.No_ == user
                 select p).Single();
    return query;
}

Code behind file:

protected void Page_Load(object sender, EventArgs e)
{
    string user = Membership.GetUser().UserName.ToString().ToUpper();
    var queryresult = CustomerClass.SelectCustomerByUser(user);
    lblStreet.Text = ?????????

}

When i set the LINQ query direclty into the code behind file I can assign lblStreet.Text directly like: lblStreet.Text = queryresult.StreetBut I want to keep the LINQ queries separatly from the code behind file.

Answer 1

The method SelectCustomerByUser returns a boxed object of Customer type so you need to unbox (type cast) it and assign properties/fields value to your user-interface.

Something like:

var queryresult = CustomerClass.SelectCustomerByUser(user) as Customer;
if(queryresult!=null)
  lblStreet.Text= queryresult.Street;  

It would be better if you change the return type of SelectCustomerByUser and use FirstOrDefault instead of Single method.

public static Customer SelectCustomerByUser(string user)
{
    var query = (from p in dc.Customers
                 where p.No_ == user
                 select p).Single();
    return query;
}