I am surprised that I can't initialize my fields in structs, why is it like that? Like:
struct MyStruct { private int a = 90; } but it's a complie time error. I don't know why it's a problem? Please explain this to me.
- Dupe of this thread.Kent Boogaart– Kent Boogaart2009-03-04 09:29:27 +00:00Commented Mar 4, 2009 at 9:29
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4 Answers
In C#, a struct cannot declare a default constructor.
The compiler moves the initialization statements to the constructor, which can't happen with a struct in C#.
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The reason is mainly performance. Consider the following,
var a = new MyStruct[1000]; If C# allowed initialization of fields in a struct then the initialization would have to be performed 1000 times, once for each element in the array. C# wanted to avoid such kinds of implicit behavior as might be found in other languages.
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mireazma
No offense but why not let the creator of the struct decide? Nothing to lose. And it would have been nice if values of fields initialized this way, would be used by
default(TheSaidStruct) instead of just zero filling.That's because your assignment is actually transformed by the compiler to be done in the default constructor. But C# structs don't have default constructors, as you can see in the link posted by Kent Boogaart.
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It's for performance. When you new up a struct with the default constructor, all it does is allocate however many bytes on the stack and initialises them to 0.
