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Cannot Modify The Return Value Of Because It Is Not A Variable C#

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The second part is due to the fact that gridNameValue Properties.Size.Width is a member of a struct. Although this would achieve your goal of having direct read-write access to the structs within the List<>, boxing the struct is really stuffing the struct into a class (a System.Object) and Where do I drop off a foot passenger in Calais (P&O)? Such a design has the advantage of allowing code like thing1.Origin = thing2.Origin; to set the state of object's origin to match that of another, but it can't warn about code Check This Out

In the second it is the value type itself. It works very simply, and very reliably, for handling window resizing. But that certainly would be problematic if different languages are used. This operates on the COPY, and any changes are lost, and the compiler does NOT warn about this.

Cannot Modify The Return Value Of Because It Is Not A Variable C#

C++ solved it, so it's solvable. I think I am saying the same thing. On Wed, 16 May 2007 09:23:09 -0700, Zytan >The problem (well, "a problem" anyway) is that lots of methods areessentially "const" even though no one's bothered to mark them as

You example struct Foo is mutable. –shf301 Jan 18 '11 at 4:35 Edited my question, added a more specific footer. –Lazlo Jan 18 '11 at 4:37 | show 2 I know it lacks this information. Compiler Error CS1612 Visual Studio 2015 Other Versions Visual Studio 2013 Visual Studio 2012 Visual Studio 2010 Visual Studio 2008 Visual Studio 2005 Visual Studio .NET 2003  Updated: July 20, 2015Cannot Cannot Modify The Return Value Of Because It Is Not A Variable List Create a project called TestSamples with a form that does nothing for now.

HTH, Sam ------------------------------------------------------------ We're hiring! Cannot Modify The Return Value Of Because It Is Not A Variable Struct With a Listfrom the array, which is always a copy of the item in the array (and if it's a copy of the reference then you can My brain apparently couldn't keep up with changing back and forth. –Alastair Pitts Jan 18 '11 at 4:45 Actuall you cant. http://stackoverflow.com/questions/18126289/cannot-modify-the-return-value-because-it-is-not-a-variable I therefore created a temp value and assigned my structure to it.

There may in fact be such an implementation, and if there is, it will have the same issue. Cannot Modify The Return Value Of Transform Rotation Because It Is Not A Variable I didn't think that this would really ever happen. This means defensively copying any incoming data to be stored in the collection, and either defensively copying or wrapping any data read from it. I'd hate for the compiler to analyze a stub function, make an automatic determination of const-ness, and somehow affect how the code around it is error-checked. (Note that optimizing the generated

Cannot Modify The Return Value Of Because It Is Not A Variable Struct

Just say no to mutablestructs, basically :) Yup! :) But, it just doesn't seem fair, since the language isn't quite 'complete', yet. http://stackoverflow.com/questions/414981/directly-modifying-listt-elements For example: interface IMap { int Size { get; set; } } struct Map: IMap { public Map(int size) { _size = size; } private int _size; public int Size { Cannot Modify The Return Value Of Because It Is Not A Variable C# using System; using System.Collections.Generic; using System.Text; namespace TestSamples { /// This structure identifies and contains the data to be sent to the event public delegate void TimeDelayEventHandler(TimeDelayEventData data); public class Cannot Modify The Return Value Of Because It Is Not A Variable Unity You'll have to add a setter for the Home property and adjust your code to: private Point mHome; public Point Home { get { return mHome; } set {mHome = value;}

If a library designer can't get const-correctness, how can they be expected to properly solve a bunch of more devious concerns (parameter checking, buffer overflows, race conditions, etc)? http://ecoflashapps.com/cannot-modify/cannot-modify-the-library-file.html If I receive written permission to use content from a paper without citing, is it plagiarism? 40 Vertices And A Connected Graph, Minimum Number Of Edges? more hot questions question feed lang-cs about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation I therefore created a temp value and assigned my structure to it. Cannot Modify The Expression Because It Is Not A Variable Struct

This incident will be reported At delivery time, client criticises the lack of some features that weren't written on my quote. I'm wondering why you declared a default constructor for a struct, though, since C# doesn't allow them. May 14 '07 #11 P: n/a Jon Skeet [C# MVP] Samuel R. this contact form Without getting into detail, I'll mention just one benefit: it's forced me to correct large architectural issues that I wasn't aware of.

When you call gridNameValueProperties.Size, you're returning a Size struct, then trying to set the Width on the returned struct (not the original). C# Struct Cannot Modify Because It Is Not A Variable Zytan May 14 '07 #5 P: n/a Peter Duniho On Mon, 14 May 2007 11:38:10 -0700, Zytan share|improve this answer answered Aug 7 '15 at 8:09 xmedeko 2,05411836 add a comment| up vote 0 down vote Its a wil guess , but the property X and Y are

It will return a copy of a value within the list, and you can operate on that copy 'till the cows come home and the item in the list will never But the reference refers to a single instance, and if you change that instance, that change is reflected whether you look at the copied reference you're using, or the original reference That means that when you say: GlobalData.Instance.MyTimeDelayData, you are getting a _copy_ of the TimeDelayData within the GlobalData object, not a _reference_ to the TimeDelayData. C# Mutable Struct In fact, because of the OOP nature of C#, you are almost always calling a method, if you are using a temporary value at all.

Feb 7 '06 #2 P: n/a Bruce Wood This isn't the code that gave you that warning. Monday, November 17, 2008 9:46 AM 0 Sign in to vote Bowthy said:I know that structs are value types and that in certain circumstances a copy of the value is retrieved.  why?

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In the same way that overloading the "new" operator bugs me about reference types versus value types, you're dealing with a situation in which the indexing operator "[]" behaves differently depending I won't accept "using". This is because, the expression has multiple parts, hence its parsing requires a storage of intermediate result which we are not allowed to modify. This instance is a stack variable.

What are the applications of taking the output of an amp with a microphone? Unless you're going to be creating and destroying millions (and I do mean _millions_) of these things, you're better off making it a class, not a struct. struct Data { public Data(){} private int someData; public int TheData { get { return someData; } set { someData = value; } } } class Sample { Data myData = In the same way that overloading the "new" operator bugs me about reference types versus value types, you're dealing with a situation in which the indexing operator "[]" behaves differently depending

It's really, really important that you post *actual* code which you've tried to compile. Pete May 15 '07 #29 P: n/a Ben Voigt After all, in C++ there's a LOT of code that doesn't modify data that isn't marked "const". Browse other questions tagged c# struct variable-assignment or ask your own question. Is adding the ‘tbl’ prefix to table names really a problem?

Things like overloading hiding certain type conversions, for example. On Wed, 16 May 2007 09:12:34 -0700, Zytan [...]But, for C#, the warning would only come up when you're potentiallymodifying a temporary. Creating symlink for a file on Windows 7 gives error Do Morpheus and his crew kill potential Ones? caching the result of calling GetHashcode) which don't change the perceivable state - no harm in that, although it would be unusual. -- Jon Skeet - http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet If

I modified your code snippet into the following runnable code, however, it does not get any runtime error on my side: struct Data { private int someData; public int TheData { It's wildly different from C++ in many ways. No, it wouldn't - because that's not how value types work. It will return a copy of a value within the list, and you can operate on that copy 'till the cows come home and the item in the list will never

Subsets of C++ used by embedded compilers, perhaps (although in my experience they overload const and make it mandatory). asked 3 years ago viewed 16940 times active 1 year ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Linked 2 Public variable of struct is not changing 24 Problem