Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <blockquote> <p>Do I understand this correctly or is it possible to declare the constraint on the interface and to have that constraint realized by the class?</p> </blockquote> <p>Correct. You <em>have</em><sup>1</sup> to declare the constraint on the type parameters for the generic class as well. Just because you named the type parameter in <code>DocumentPrinter&lt;T&gt;</code> to have the same name as the type parameter in <code>IDocumentPrinter&lt;T&gt;</code> does not mean that they are the same types. When you declare</p> <pre><code>public class DocumentPrinter&lt;T&gt; : IDocumentPrinter&lt;T&gt; </code></pre> <p>you are in fact saying to use <code>T</code> that parameterizes <code>DocumentPrinter&lt;T&gt;</code> to parameterize <code>IDocumentPrinter&lt;T&gt;</code> and <em>now</em> they are the same types. But for that to be legal, <code>T</code> from <code>DocumentPrinter&lt;T&gt;</code> has to satisfy all constraints on the type parameter for <code>IDocumentPrinter&lt;T&gt;</code>. Thus, you must explicitly say that <code>T</code> satisfies <code>T : IFooDoc</code>.</p> <p><sup>1</sup>: Apparently I need to state this explicitly. If you don't do something the language specification requires you to do, your code won't compile. The language specification requires that when you parameterize a generic type, the type that you parameterize it with must satisfy all the constraints on that type parameter for that generic type. If you do not, your code won't compile.</p>
    singulars
    1. This table or related slice is empty.
    1. POC# Interface Contraints
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USjason
    1. USjason
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POC# Interface Contraints
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThis is misleading, you don't have to add the constraint to the class to be able to access the members, you have to add it for the code to compile.
      singulars
      1. PO
      1. USsvick
    2. CO@svick: The question as stated is "*Do I understand this correctly or is it possible to declare the constraint on the interface and to have that constraint realized by the class?*" Not sure how my answer is misleading. If you *have to declare the constraint* as I specified on my answer, there is an implicit *if you don't, the code won't compile* since any time you do not do something that language *requires* you to do, you have code that won't compile. But again, the question was *do I have to do this, or is there a way to do it without being explicit.* I answered that question. Downovting?
      singulars
      1. PO
      1. USjason
    3. COThe question says: “It seems that I must explicitly declare an interface constraint upon the class itself *if I am to access members declared by the type*.” To me, that indicates that the OP *doesn't realize the code won't compile*. That's why I think it's important to stress that out.
      singulars
      1. PO
      1. USsvick
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload