Let's examine the MSIL code generated for the following generic method: public static U BoxValue<T, U>(T value) where T : struct, U where U : class { return value; } Look: .method public hidebysig static !!U BoxValue<valuetype .ctor ([mscorlib]System.ValueType, !!U) T,class U>(!!T 'value') cil managed { .maxstack 8 IL_00...
I need a method that returns an instance of the supplied class type. Let's assume that the supplied types are limited to such that an "empty" instance of them can be created. For instance, supplying String.class would return an empty String, supplying an Integer.class would return an Integer whose initial value is zero, and so on. But ho...
Since there is no implicit conversion between Mvc.JsonResult and Mvc.ViewResult I cannot just utilize a conditional operator but instead end up with a cast. Which leads me to my question is the performance hit I will take for boxing the JsonResult worth it or should I just do a normal if...else block? The code below appears inside a no...
Guys, I'm writing a class to represent a row from a SQL query. I want the field data to be accessed via the indexer property of the class. This is straightforward enough if I load the data into an internal List of Object. I've already tried this and am not happy with the boxing for the primitives. Boxing increases the memory requirement...
public void DoSomething(params object[] args) { // ... } The problem with the above signature is that every value-type that will be passed to that method will be boxed implicitly, and this is serious performance issue for me. Is there a way to declear a method that accepts variable number of arguments without boxing the value-type...
I got some weird exception when trying to compile this: Byte b = 2; if (b < new Integer(5)) { ... } Is it a valid check (unboxing-implicit cast - unboxing)? ...
So I understand what boxing and unboxing is. When's it come up in real-world code, or in what examples is it an issue? I can't imagine doing something like this example: int i = 123; object o = i; // Boxing int j = (int)o; // Unboxing ...but that's almost certainly extremely oversimplified and I might have even done boxing/...
I am a big fan of auto-boxing in Java as it saves a lot of ugly boiler plate code. However I have found auto-unboxing to be confusing in some circumstances where the Number object may be null. Is there any way to detect where auto-unboxing is occurring in a codebase with a javac warning? Any other solution to detect occurrences of unboxi...
Hi I'm using ADO.NET to communicate some db, and searching for a way to avoid boxing when setting the DbParameter.Value property to value-type. Is there a way to avoid boxing in DbParameter.Value? Thanks. ...
Though I know what boxing and unboxing is. But I can't comprehend the real use of it. Why and where should I use it. short s=25; object objshort=s; //Boxing short anothershort=(short)objshort; //UnBoxing Please help. Thanks in advance. ...
Hi, How can I store a variable of type int32_t (e.g. for ABPropertyID) in an NSDictionary? [NSNumber numberWithInt:...] doesn't seem to work. Thanks From the comments: NSLog(@" %@ %@ ", [NSNumber numberWithLong:kABPersonFirstNameProperty], kABPersonFirstNameProperty); Prints: 0 (null) Any ideas? ...
I was wondering, does a class get boxed? I always assumed every class had a virtual table which can be used to identify the class, so does it need to be boxed? ...
Hi! I'm wondering whether boxing a value type in an object is a special case or whether the "box" constructed by .NET becomes garbage (that the GC has to collect) after any references to it are dropped. For example, StringBuilder.AppendFormat() has these overloads: StringBuilder.AppendFormat(string format, object arg0); StringBuilder....
Hello, everyone! I need to do lots of conversions between primitivetype[] and boxedtype[] (both directions). Such as: Integer[] <-> int[], Double[] <-> double[], ... I wanted to know, if there's some quasi-standards APIs out there, which provide such functionality, before I write such utility methods by myself. Java has 8 primitive ty...
I'm working on creating my own DI framework that creates delegate factories as a learning exercise. My way of building typed delegates is to use expressions to create a function that calls a static method with reference to my container and any constructor params. This thrown up an interesting question with regards to value types. Whic...
Is there any difference between the 2 methods below for calculating c ... specifically boxing/unboxing issues? Dim a As Integer? = 10 Dim b As Integer? = Nothing Dim c As Integer ' Method 1 c = If(a, 0) + If(b, 0) ' Method 2 c = a.GetValueOrDefault(0) + b.GetValueOrDefault(0) ...
Those of us who've worked in VB/VB.NET have seen code similar to this abomination: Dim name As String = IIf(obj Is Nothing, "", obj.Name) I say "abomination" for three simple reasons: IIf is a function, all of whose parameters are evaluated; hence if obj is nothing in the above call then a NullReferenceException will be thrown. This...
I am learning WPF and it seems like some properties like Content are of type Object. When you have a very complex UI with 1000s of controls, would this be a problem with boxing, etc? I see that this provides a lot of power (having Content to take anything), but just thought I should ask people's opinions about this. ...
Is there a implemented Java method in jdk to do this? public static Byte[] box(byte[] byteArray) { Byte[] box = new Byte[byteArray.length]; for (int i = 0; i < box.length; i++) { box[i] = byteArray[i]; } return box; } ...
I'm working on an extension method that's only applicable to reference types. I think, however, it's currently boxing and unboxing the the value. How can I avoid this? namespace System { public static class SystemExtensions { public static TResult GetOrDefaultIfNull<T, TResult>(this T obj, Func<T, TResult> getValue, TR...