Object initializers. [modified]
-
John Simmons / outlaw programmer wrote:
Why is that better than writing the appropriate constructor
As I said in my first post. Lets assume that your class contains 20 properties, all of those recieve default values in the default ctor. And the user only wants to init custom values in 5 of them.. (Think winforms control or such, eg a grid) Should you create a constructor for each possible combination of properties that the user _might_ want to set? No way..
Not to mention if they're all the same type you can't create a ctors for all of them. That said, this is just a return of optional parameters. Personally I'd prefer a syntax of
FooBar myFooBar = new FooBar(1,2,,,5,,,8,,,,,,15,,,,19,20);and a ctor that looked likeFooBar(optional int param1, optional int param2, optional int param3,.... ) {...}Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
-
This falls neatly under the category of "Just because you *can* do it, doesn't mean you *should* do it". Why is that better than writing the appropriate constructor and using
new Person("John", "Simmons");? Further, an appropriately designed class initializes all of its properties when it's instantiated. This new feature of .Net appears to propagate lazy programmers."Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001Ten! Or we should be able to use something like the syntax that Attributes use.
-
Ah, more new "features" to avoid. I wish they'd add the features the I want.
I am still holding out for them to add a DoAllMyWork class ;P
-
I am still holding out for them to add a DoAllMyWork class ;P
You can make one by inheriting
HireRentACoderand implementingCheapOutsourcing().Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
-
You can make one by inheriting
HireRentACoderand implementingCheapOutsourcing().Today's lesson is brought to you by the word "niggardly". Remember kids, don't attribute to racism what can be explained by Scandinavian language roots. -- Robert Royall
Do you implement CheapOutsourcing() in VB thus:
Me = Nothing -
Do you implement CheapOutsourcing() in VB thus:
Me = Nothing -
Pete O'Hanlon wrote:
You can't initialize objects like this.
That's correct but the above code compiles. But foo.Name is not initialized. That's why it is a subtle bug ;)
Giorgi Dalakishvili #region signature my articles My blog[^] #endregion
-
I didn't know you could do this (citing the correct way to do it):
Foo foo = new Foo() { Description="Blah", Name="name"};
Putting the constructor body here is, IMHO, bad programming technique.
"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001It translates to
Foo foo = new Foo();
foo.Description = "Blah";
foo.Name = "name";How's that bad programming technique?
-- Kein Mitleid Für Die Mehrheit
-
class Foo
{
public string Description { get; set; }
public String Name { get; set; }
}public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}private void InitFoo()
{
Foo foo = new Foo() { Description = Name = "name" };
}
}After running
InitFoomethod foo.Name is not initialized. Can you spot the bug? You can see answer at my blog post: Object Initializers and Possible Bugs[^]Giorgi Dalakishvili #region signature my articles My blog[^] #endregion
modified on Friday, September 19, 2008 2:19 AM
Really subtle !! I changed the properties order as Mirko1980 said, Visual Studio is telling me 'Description' does not exist in the current context.:confused: I tend to think that if you do a one step initialization, you can put just one member of your object at the most left side of the assignment, one and just one; why don't ask me :wtf:
Best wishes, Redwan Al-Bougha
-
This falls neatly under the category of "Just because you *can* do it, doesn't mean you *should* do it". Why is that better than writing the appropriate constructor and using
new Person("John", "Simmons");? Further, an appropriately designed class initializes all of its properties when it's instantiated. This new feature of .Net appears to propagate lazy programmers."Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001I look at it as one of those "if you don't like it, don't use it" things. Frankly, I think it'll make code cleaner and more concise. Instead of 10 different constructors for various combination's of things you MIGHT pass in, this syntax allows you to explicitly initialize the object how you want it. The only real change I've seen in C# so far since its creation that truly scares me is the 'dynamic' keyword in C# 4. I like the idea of it when you're trying to work with interop (like access the Excel object library, for instance), but like the 'unsafe' keyword, you should have to tell the compiler explicitly that you mean it. And THEN, it should only be usable on interop types. You should also never be able to return a dynamic type from methods or properties. In other words:
// Allowed, if a DYNAMIC compiler flag is enabled.
dynamic range = Excel.Application.CurrentWorkbook.CurrentSheet.Range("A1:B3");// NEVER allowed.
dynamic x = 3;Kyosa Jamie Nordmeyer - Taekwondo Yi (2nd) Dan Portland, Oregon, USA
