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Closed 10 years ago.
Consider this:
public class Minesweeper extends MIDlet implements CommandListener {
public static String error = "";
public void startApp() throws MIDletStateChangeException {
try{
int int = 5;
} catch (Exception e) {
error = e.toString();
}
}
}
int is an invalid name for an int, so surely the error should be caught and registered in error? (This error is there on purpose so I can catch it)
You've probably guessed it though, the error doesn't seem to be caught, and the app stops with a java/lang/Error Unresolved compilation problem: syntax error on token 'int'....
What am I doing wrong.
(BTW, this was just a test so I knew I could catch errors properly, I'm obviously not going to use that code in a final version.)
Here is your problem - "int int = 5;" - you cannot use "int" as a variable name ;)
You are trying to use a reserved word as a variable name. The compilation problem has nothing to do with your try-catch block working or not working, the compiler never gets that far.
Try/catch blocks can't be used for that kind of error.
If you try loading a file that isn't there, then it'll trigger. Try this:
Image img = Image.createImage("blabla.png");
Related
One would think that in C# 8.0 you should be able to do the following (according to this (1st snippet)):
public interface IRestApiClient : IRestClient
{
...
Task<T> PostPrivateAsync<T>(string action, OrderedDictionary<string, object> parameters = null, DeserializeCustom<T> deserializer = null)
{
return QueryPrivateAsync(Method.POST, action, parameters, deserializer);
}
...
}
public class SpecificClient : ExchangeClient, IRestApiClient, IRestHtmlClient, ISeleniumClient, IWebSocketClient
{
}
The example above won't compile because the interface members need to be explicitly and wholly implemented (including the methods supplying the default logic)
So one would think that the following should work:
public interface IRestApiClient : IRestClient
{
...
Task<T> PostPrivateAsync<T>(string action, OrderedDictionary<string, object> parameters = null, DeserializeCustom<T> deserializer = null)
{
return QueryPrivateAsync(Method.POST, action, parameters, deserializer);
}
...
}
public class SpecificClient : ExchangeClient, IRestApiClient, IRestHtmlClient, ISeleniumClient, IWebSocketClient
{
...
public async Task<T> PostPrivateAsync<T>(string action, OrderedDictionary<string, object> parameters = null, DeserializeCustom<T> deserializer = null)
=> await ((IRestApiClient) this).PostPrivateAsync(action, parameters, deserializer);
...
}
Nope, it looks like this method is recursive (despite the upcast) and will cause our favorite Stack Overflow exception.
So my question is (abstracting from the fact that I could change the design in my example), is there a way of keeping the implementation for a specific method default, preferably without the necessity of resorting to hacky or Static Helper Extension methods? I could call static extension method in both interface and the class but it kind of defeats the purpose of this feature.
// EDIT
I must admit it confuses me and it appears I am missing something critical that is obvious to other people. I didn't provide additional info because I didn't consider my issue to be code specific. Lets look at this simple example (taken from the website I linked on the beginning of my post):
According to #Panagiotis Kanavos comment: No, default members don't need to be implemented (...) what I screenshoted should not be true. Can sb please enlighten me?
// EDIT 2
As you can see I am properly targeting .NET CORE 3.0 with C# 8.0.
ERRORS:
Interface method cannot declare a body
Interface member 'void CryptoBotCoreMVC.IDefaultInterfaceMethod.DefaultMethod()' is not implemented
To answer the question in the comments: I didn't specify LangVersion explicitly in the .csproj file.
// EDIT 3
The issue was ReSharper, see:
https://stackoverflow.com/a/58614702/3783852
My comment have been deleted, presumably by the owner of the answer so I'll write it here: the clue was the fact that there was actually no error numbers, but the compilation was blocked. It turned out that there is an option to block compilation when these errors occur in ReSharper.
It seems that in the end this is a possible duplicate, but getting to this conclusion was quite a journey :).
The issue is caused by ReSharper, reference:
https://youtrack.jetbrains.com/issue/RSRP-474628
It appears that the problem will be resolved in version v2019.3 and we currently have v2019.2.3. You can setup ReSharper to block compilation depending on issue severity, the workaround is to disable this feature for the time being.
Back for some help! So I am making an AIR application that loads SWF's into a container to be viewed by the user. However when I load the files into their containers, the SWF's that are loaded are unable to execute their own code. IE press an invisible button on the loaded SWF and it changes colour. I tried to google solutions for this since Security.allowDomain("*"); is throwing this error in flash. However from what I have read, AIR doesn't allow loaded swfs to execute code for some security reason but im not 100% sure on that either.
SecurityError: Error #3207: Application-sandbox content cannot access this feature.
at flash.system::Security$/allowDomain()
at BugFree()[D:\Desktop\BugFree\BugFree.as:72]
Without the Allow domain it throws this security error when attempting to click the invisible button.
*** Security Sandbox Violation ***
SecurityDomain 'file:///D:/Desktop/Rewritten Tester/TechDemoSwordNew.swf'
tried to access incompatible context 'app:/BugFree.swf'
*** Security Sandbox Violation ***
SecurityDomain 'file:///D:/Desktop/Rewritten Tester/TechDemoSwordNew.swf'
tried to access incompatible context 'app:/BugFree.swf'
SecurityError: Error #2047: Security sandbox violation: parent:
file:///D:/Desktop/Rewritten Tester/TechDemoSwordNew.swf cannot access
app:/BugFree.swf.
at flash.display::DisplayObject/get parent()
at TechDemoSwordNew_fla::Button_Play_21/onButtonPress()
This only shows in the Animate output bar. When I publish it, with application with runtime embeded, and open the exe it throws no errors but the invisible button still doesnt work.
Here is the code for the swf being loaded.
btnButton.addEventListener(MouseEvent.CLICK, onButtonPress, false, 0, true);
function onButtonPress(event:MouseEvent):void
{
MovieClip(parent).play();
}
stop();
This is timeline code within the button since that is how the game company who put my item in game did it. I originally submitted it with it all done in classes but that is besides the point. When the button is pressed the loaded SWF should play and then stop. But I get the above mentioned Sandbox violation.
The code used to load the SWF is below
public function WeaponLoad()
{
if(FileMenu.WeaponFileTxt.text != "")
{
LoadWeapon(FileMenu.WeaponFile.nativePath);
}
else if(FileMenu.WeaponFileTxt.text == "")
{
Character.mcChar.weapon.removeChildAt(0);
Character.mcChar.weaponOff.removeChildAt(0);
}
}
public function LoadWeapon(strFilePath: String)
{
WeaponLoader.contentLoaderInfo.addEventListener(Event.COMPLETE, CompleteWeaponLoad);
WeaponLoader.load(new URLRequest(strFilePath), new LoaderContext(false, new ApplicationDomain(ApplicationDomain.currentDomain)));
}
public function CompleteWeaponLoad(e: Event)
{
var WeaponClass: Class;
if (MiscMenu.WeaponSelect.MainClick.currentFrame != 3)
{
try
{
trace("WeaponOff");
WeaponClass = WeaponLoader.contentLoaderInfo.applicationDomain.getDefinition(FileMenu.WeaponLinkTxt.text) as Class;
this.Character.mcChar.weapon.removeChildAt(0);
this.Character.mcChar.weaponOff.removeChildAt(0);
this.Character.mcChar.weapon.addChild(new(WeaponClass)());
}
catch (err: Error)
{
trace("Either the weapon class doesnt exist or it is wrong");
this.Character.mcChar.weapon.removeChildAt(0);
this.Character.mcChar.weaponOff.removeChildAt(0);
}
}
else if (MiscMenu.WeaponSelect.MainClick.currentFrame == 3)
{
try
{
WeaponClass = WeaponLoader.contentLoaderInfo.applicationDomain.getDefinition(FileMenu.WeaponLinkTxt.text) as Class;
this.Character.mcChar.weapon.removeChildAt(0);
this.Character.mcChar.weaponOff.removeChildAt(0);
this.Character.mcChar.weapon.addChild(new(WeaponClass)());
this.Character.mcChar.weaponOff.addChild(new(WeaponClass)());
}
catch (err: Error)
{
trace("Either the weapon class doesnt exist or it is wrong");
this.Character.mcChar.weapon.removeChildAt(0);
this.Character.mcChar.weaponOff.removeChildAt(0);
}
}
}
Any help would be apreciated since I have no idea how to change any security sandbox settings within the publish settings since it is greyed out for me. Like I said I tried googling it but I couldn't seem to come up with any answers. Also worth noting is im a self taught novice and I do not know a lot of things in regards to AS3. I know my codes could be cleaner and I plan to clean it up and properly reduce memory consumption once I have the base program up and running. Thank you for the help!
It seems that you're not setting the application domain properly. Here is the code included in as3 documentation:
var loader:Loader = new Loader();
var url:URLRequest = new URLRequest("[file path].swf");
var loaderContext:LoaderContext = new LoaderContext(false, ApplicationDomain.currentDomain, null);
loader.load(url, loaderContext);
Use it in your LoadWeapon function.
In the meantime try not to use Uppercase letters for starting variables and method names. In ActionScript names starting with Uppercase represent Class names. It will widely improve readability of your code.
Can't you bundle your swfs with the AIR app and use File class to load them? If you want to use classes from the swfs, maybe consider making swc library?
Alright, this is probably the biggest program i have ever written. I use task in it once so that on first run it will search all available files and folders for certain things. Everything works...well, did work. Now when i start the program after adding a few more features in. It is throwing stack overflow errors on things that never had a problem before.
My first one was right in the begging it threw on a simple return of,
return System.Environment.GetFolderPath(Environment.SpecialFolder.CommonDocuments)
i changed it to just return
public string BaseUpdaterPath { get { return "C:\\Users\\Public\\Documents"; } }
and it started working again.
it got alittle further into the program untill it runs a check to see if a specific path exists.
if (File.Exists(pathINI))
pathini is defined earlier as
string pathINI = (BaseProductPath + "\\" + Name + ".ini");
and baseproduct is
public string BaseProductPath { get { return BaseUpdaterPath + "\\" + Name; } }
these are things that should not be breaking. My error is this
An unhandled exception of type 'System.StackOverflowException' occurred in mscorlib.dll
with more investigation turns into this
Source Evaluation of method System.Exception.get_Source requires calling method System.Reflection.RuntimeMethodInfo.CreateDelegate, which cannot be called in this context. string
I can only imagine this has something to do with threading and the initial search that I am doing if this is the programs first run time.
If i can provide anymore information that i may have overlooked in my details i would be happy to provide it. I have not seen errors like this before that don't really give you much to go off of.
I may just end up throwing up a splash screen during that initial search if it's going to keep causing problems like this and have the rest of the program wait on that task.
UPDATE
I just stepped through my program starting at different steps and i was able to get past that check it kept kicking it out at. Then i got to a different if(foo == bar) and visual studio did this strange thing where it popped up a little loading window and said evaluating BAR then killed the program with
has exited with code -2147023895 (0x800703e9).
wtf is going on lmao
Another update incase anyone runs into this. I have a product preselected when i started up the programming, i wrote checks in to accommodate this however....it blocked me from being able to see what is really happening.
I disabled some code and let the thing run and after a while i found this little bastard popping up on the console
Exception thrown: 'System.IO.PathTooLongException' in mscorlib.dll
Exception thrown: 'System.IO.PathTooLongException' in mscorlib.dll
Exception thrown: 'System.IO.PathTooLongException' in mscorlib.dll
Exception thrown: 'System.IO.PathTooLongException' in mscorlib.dll
now i gotta track that down to wherever the hell it's throwing 5000 times and i should be good to go.
Update again if anyone cares.
I found out that even i caught and threw the exception away it was still getting stackoverflow in windows.old because they have tons of folders and files and i was running out of memory. My solution at this point is during the recursive file check to just discard anyfolder in windows.old. Cant think of a better way.
THE EPIC CONCLUSION...I AM A DUMBASS
i was having two properties check eachother
public bool IsInstalled { get
{
if (DefaultInstalledpath != null || DefaultInstalledpath != "Not Installed")
{
return true;
}
else
{
return false;
}
}
public string DefaultInstalledpath
{
get
{
else if(!File.Exists(pathTXT) && IsInstalled == true)
{
return "Discovering! Please Wait...";
}
.........
i don't wanna talk about the rabbit hole i just fell down
I'm working in java me. I created two visual designs, First.java and Second.java both of which contains form displayables.
I added an Ok command to a form in First.Java and the user is expected to switch to SecondForm in Second.java but I get this error non-static method getSecondForm() cannot be referenced from a static context.
How can I fix this?
Both files are in the same package. Here's the source code
public void commandAction (Command command, Displayable displayable) {
if (displayable == firstForm) {
if (command == exitCommand) {
exitMIDlet();
} else if (command == okCommand) {
switchDisplayable(null, Second.getSecondForm());
}
}
}
You need to change declaration of the method getSecondForm in Second.java to make it static.
If it currently looks like
Displayable getSecondForm() //... whatever code is there
then after change it should look like
static Displayable getSecondForm() //... whatever code is there
Note above change will fix the non-static method getSecondForm... error you mentioned but there is a chance that it will cause new compilation errors in file Second.java. You will need to fix these new errors, most likely by adding couple static keywords here and there, similar to how it is shown above.
Note this is java language basic stuff; if you get stuck fixing this, consider taking a break to study some tutorial for beginners.
Since I don't know exactly what part of it alone that triggers the error, I'm not entirely sure how to better label it.
This question is a by-product of the SO question c# code seems to get optimized in an invalid way such that an object value becomes null, which I attempted to help Gary with yesterday evening. He was the one that found out that there was a problem, I've just reduced the problem to a simpler project, and want verification before I go further with it, hence this question here.
I'll post a note on Microsoft Connect if others can verify that they too get this problem, and of course I hope that either Jon, Mads or Eric will take a look at it as well :)
It involves:
3 projects, 2 of which are class libraries, one of which is a console program (this last one isn't needed to reproduce the problem, but just executing this shows the problem, whereas you need to use reflector and look at the compiled code if you don't add it)
Incomplete references and type inference
Generics
The code is available here: code repository.
I'll post a description below of how to make the projects if you rather want to get your hands dirty.
The problem exhibits itself by producing an invalid cast in a method call, before returning a simple generic list, casting it to something strange before returning it. The original code ended up with a cast to a boolean, yes, a boolean. The compiler added a cast from a List<SomeEntityObject> to a boolean, before returning the result, and the method signature said that it would return a List<SomeEntityObject>. This in turn leads to odd problems at runtime, everything from the result of the method call being considered "optimized away" (the original question), or a crash with either BadImageFormatException or InvalidProgramException or one of the similar exceptions.
During my work to reproduce this, I've seen a cast to void[], and the current version of my code now casts to a TypedReference. In one case, Reflector crashes so most likely the code was beyond hope in that case. Your mileage might vary.
Here's what to do to reproduce it:
Note: There is likely that there are more minimal forms that will reproduce the problem, but moving all the code to just one project made it go away. Removing the generics from the classes also makes the problem go away. The code below reproduces the problem each time for me, so I'm leaving it as is.
I apologize for the escaped html characters in the code below, this is Markdown playing a trick on me, if anyone knows how I can rectify it, please let me know, or just edit the question
Create a new Visual Studio 2010 solution containing a console application, for .NET 4.0
Add two new projects, both class libraries, also .NET 4.0 (I'm going to assume they're named ClassLibrary1 and ClassLibrary2)
Adjust all the projects to use the full .NET 4.0 runtime, not just the client profile
Add a reference in the console project to ClassLibrary2
Add a reference in ClassLibrary2 to ClassLibrary 1
Remove the two Class1.cs files that was added by default to the class libraries
In ClassLibrary1, add a reference to System.Runtime.Caching
Add a new file to ClassLibrary1, call it DummyCache.cs, and paste in the following code:
using System;
using System.Collections.Generic;
using System.Runtime.Caching;
namespace ClassLibrary1
{
public class DummyCache<TModel> where TModel : new()
{
public void TriggerMethod<T>()
{
}
// Try commenting this out, note that it is never called!
public void TriggerMethod<T>(T value, CacheItemPolicy policy)
{
}
public CacheItemPolicy GetDefaultCacheItemPolicy()
{
return null;
}
public CacheItemPolicy GetDefaultCacheItemPolicy(IEnumerable<string> dependentKeys, bool createInsertDependency = false)
{
return null;
}
}
}
Add a new file to ClassLibrary2, call it Dummy.cs and paste in the following code:
using System;
using System.Collections.Generic;
using ClassLibrary1;
namespace ClassLibrary2
{
public class Dummy
{
private DummyCache<Dummy> Cache { get; set; }
public void TryCommentingMeOut()
{
Cache.TriggerMethod<Dummy>();
}
public List<Dummy> GetDummies()
{
var policy = Cache.GetDefaultCacheItemPolicy();
return new List<Dummy>();
}
}
}
Paste in the following code in Program.cs in the console project:
using System;
using System.Collections.Generic;
using ClassLibrary2;
namespace ConsoleApplication23
{
class Program
{
static void Main(string[] args)
{
Dummy dummy = new Dummy();
// This will crash with InvalidProgramException
// or BadImageFormatException, or a similar exception
List<Dummy> dummies = dummy.GetDummies();
}
}
}
Build, and ensure there are no compiler errors
Now try running the program. This should crash with one of the more horrible exceptions. I've seen both InvalidProgramException and BadImageFormatException, depending on what the cast ended up as
Look at the generated code of Dummy.GetDummies in Reflector. The source code looks like this:
public List<Dummy> GetDummies()
{
var policy = Cache.GetDefaultCacheItemPolicy();
return new List<Dummy>();
}
however reflector says (for me, it might differ in which cast it chose for you, and in one case Reflector even crashed):
public List<Dummy> GetDummies()
{
List<Dummy> policy = (List<Dummy>)this.Cache.GetDefaultCacheItemPolicy();
TypedReference CS$1$0000 = (TypedReference) new List<Dummy>();
return (List<Dummy>) CS$1$0000;
}
Now, here's a couple of odd things, the above crash/invalid code aside:
Library2, which has Dummy.GetDummies, performs a call to get the default cache policy on the class from Library1. It uses type inference var policy = ..., and the result is an CacheItemPolicy object (null in the code, but type is important).
However, ClassLibrary2 does not have a reference to System.Runtime.Caching, so it should not compile.
And indeed, if you comment out the method in Dummy that is named TryCommentingMeOut, you get:
The type 'System.Runtime.Caching.CacheItemPolicy' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Runtime.Caching, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
Why having this method present makes the compiler happy I don't know, and I don't even know if this is linked to the current problem or not. Perhaps it is a second bug.
There is a similar method in DummyCache, if you restore the method in Dummy, so that the code again compiles, and then comment out the method in DummyCache that has the "Try commenting this out" comment above it, you get the same compiler error
OK, I downloaded your code and can confirm the problem as described.
I have not done any extensive tinkering with this, but when I run & reflector a Release build all seems OK (= null ref exception and clean disassembly).
Reflector (6.10.11) crashed on the Debug builds.
One more experiment: I wondered about the use of CacheItemPolicies so I replaced it with my own MyCacheItemPolicy (in a 3rd classlib) and the same BadImageFormat exception pops up.
The exception mentions : {"Bad binary signature. (Exception from HRESULT: 0x80131192)"}