Question

I was wondering, after having read this question… he has this code:

public static T FindOrCreate<T>(this Table<T> table, Func<T, bool> find)      where T : new() {     T val = table.FirstOrDefault(find);     if (val == null)     {         val = new T();         table.InsertOnSubmit(val);     }     return val; } 

Would it be possible to also send in that new item as another Func? I mean, of course it would. But, would that have been created already? Or would it be created first when you actually run the Func? Lets say you have this:

public static T FindOrCreate<T>(this Table<T> table, Func<T, bool> find, Func<T> replacement)      where T : new() {     T val = table.FirstOrDefault(find);     if (val == null)     {         val = replacement();         table.InsertOnSubmit(val);     }     return val; } 

And then called that by doing this:

var invoiceDb = ctx.Invoices.FindOrCreate(a => a.InvoicerId == InvoicerId                                             && a.Number == invoiceNumber,                                           () => new Invoice()); invoiceDb.Number = invoiceNumber; 

If that invoice was found, would that new Invoice have been created? Or is that code ran not until the function is actually called? or how does that work?

Answer 1

In this case you’re passing a delegate so the

() => new Invoice() 

code is not called until the

val = replacement(); 

line