While debugging I tried to save intermediate results of a calculation to a variable so that when a breakpoint condition is met I could check that value. However C# compiler (or CLR) optimized away that variable as unused. I solved the problem by making the variable a public field of the class, however I'd like to know if there is a straightforward solution to this problem.
"Optimize code" checkbox is unchecked. The build configuration is Debug.
Edit: Found that it only affects some unused variables in iterators that would normally end up as fields in the automatically generated iterator class; unused variables that are scoped within blocks not containing yield statements are retained.
The lazy option would be.... use the value, ideally in a way that doesn't allow it to be held on the stack. For example:
var tmp = SomeMethod();
// your other code
Debug.WriteLine(tmp);
the use of the value as an argument means it must be retained, but that line is automatically not compiled into release builds.
However! I must emphasize that locals are pretty-much always retained in an unoptimized/debug build, so I'm finding the scenario from the question hard to envisage.
If you are using Visual Studio, why not just add a breakpoint on the line following the line on which the calculation is being made, and then you can simply hover over the calculation to see the result in the intellisense/tooltip popup? I also think that you can add the calculation to the "watch" screen and view the result that way as well.
This is usually how I view the results of things I am debugging. Alternatively, you could just use the temp variable you created in some simple way to avoid getting the warning.
For example:
Console.Write(tempVariable);
Handy utility:
using static _globals;
static class _globals
{
[MethodImpl(MethodImplOptions.NoInlining), DebuggerHidden]
public static void Nop<T>(out T x) => x = default(T);
};
class Program
{
static void Main()
{
int i; // unreferenced variable
/// ...
Nop(out i);
/// ...
}
};
You need uncheck options "Optimize code" in project options for Debug build.
In my case "Optimize code" option was unchecked, still I was facing this issue. I checked it, build project then unchecked it and buid project again. This fixed issue for me.
I have a bigger (c#) WPF application with n-classes and m-methods. I would like to place in every single method a breakpoint, so everytime i press a button in my application or any method gets called, i would like the application in VS2010 to hit that breakpoint. I want to understand the flow/progress of the application.
And since i have many methods i would rather not place manually in every and each of them a breakpoint.
Is there any command or tool to place everywhere in my VS2010 solution a breakpoint?
edit: maybe something like the following addin: http://weblogs.asp.net/uruit/archive/2011/08/04/visual-studio-2010-addin-setting-a-class-breakpoint.aspx
edit2: there are some answers but none of them seems like the straight forward easy solution. Anything else?
EDIT: tested only with C++
I came across this article that shows how to set a breakpoint at the beginning of every method in a class. I've tested it with VS 2010. The basic process (when using Visual C++) is:
Go to Debug > New Breakpoint > Breakpoint at Function (Ctrl + B).
In the Function field, insert MyClass::*
This will show up as a single breakpoint in the Breakpoints window, but as soon as one of MyClass's methods is hit, you'll see a breakpoint at the beginning of every function in MyClass, and all of these will be "children" of the original breakpoint in the Breakpoints window.
I imagine this works with C# as well.
This answer suggests a macro that will do as you ask, but my personal recommendation would be to use a profiler instead - one that lets you pause and resume profiling on the fly (nearly all of the commercial profilers do), and then hit the "Start Profiling" button just before you do your button click. Viewing the call tree in the profiler is often a very convenient way of gaining insight into what an application is doing, much more than stepping through in the debugger.
UPDATE: This feature exists in a Visual Studio extension that I'm working on called OzCode. With OzCode, when you click on the icon next to the class definition, you'll see the QuickAction:
Here's a quick and dirty way to do it using a simple text replace:
Format your C# file so that all of the indentations are lined up. You can do this in Edit > Advanced > Format Document
Open up text replace with Ctrl+H
Set the "Text to Find" field this "^ {".
Set the "Replace" field to this " {System.Diagnostics.Debugger.Break();"
Click the little "Use Regular Expressions" button in the window
Click "Replace All" or hit Alt+A
If your file has any classes with nested enums, classes, or structs, you'll have some compiler errors. Remove the Debug calls from them until your code compiles. If your nested classes have their own methods, you'll have to run this process again with more tabs in the replace strings.
How this works: This uses the Visual Studio document formatter and assumes that all methods in a file start with two tabs and then a "{". So any line that starts with two tabs and a "{" will get replaced with the same two tabs, the same "{", and a call to the Debugger.
If your file has nested enums etc., you'll get compiler errors because the text replace doesn't discriminate between methods and enums. For example, you'll see this:
enum MyColors
{ System.Diagnostics.Debugger.Break(); //error here
Red,
Green,
Blue,
}
If you want the ability to disable these breakpoints, the best way I can think of is a simple bool. Somewhere in your code, insert this:
#if DEBUG
private static bool _ignoreDebug = false;
#endif
(I put the #if DEBUG in there as a flag that this code is only for debugging. It's not necessary) Then in step #4 above, use this replace string instead:
" {if(!_ignoreDebug){System.Diagnostics.Debugger.Break();}"
Then when you hit a breakpoint and don't want to hit any more, in the watch window type this and hit enter _ignoreDebug = true. To turn it back on you'll need to insert a manual breakpoint somewhere that has access to the _ignoreDebug bool.
To remove all of this from your code, either do another text replace, or just edit undo everything.
I think you create an 'aspect' for it using a tool like: postsharp
Aspect oriented programming allows you to add code to the start or end of every method (through a postprocessing step). So it's trivial to add the line:
System.Diagnostics.Debugger.Break()
to every method (without actually editing all your sourcecode).
More typically it is used to add log statements to the beginning of every method like: "Entering method DrawLine(x=30,y=80,z=12)" and at the end of a method: "Leaving method DrawLine(x,y,z)". Which makes following the flow of your program easy
You can use my Runtime Flow extension to see all methods called after press of a button without setting breakpoints.
You can use System.Diagnostics.Debugger.Break() on entry to your method.
Something like this perhaps with a bool that you set at the scope?
#if DEBUG
if (BreakPointEveryMethod)
System.Diagnostics.Debugger.Break();
#endif
There will be a quick way too add this for sure in notepad++ but I am not sure there is a quick and easy way for you to achieve this through a simple command line.
In my program there is a variable that sometimes gets the value of -1. I want to find out exactly where in the code this is happening. In Visual C#, is there a tool or method I can use so that when the variable becomes -1, the debugging process pauses, and I'm taken to the line of code where the variable is set to -1?
Yes! Conditional breakpoint. Click as if normally adding a breakpoint, then right click the red dot, and choose "condition". Put the statement in brackets.
23: x++;
[x] Condition: (x == 2)
What type of variable? If it is a property, add a conditional breakpoint in the setter. Once that line is hit, take a look at the call stack to see where it was set from.
As suggested, turn the var into property, put breakpoint on the setter and when u hit the breakpoint, theres a windows in VS to see the call stack (debug -> windows -> call stack)
call stack is stack of calls - from what methods or functions you got to the point where you are. (main -> connectToDatabase -> connectToPort -> sendTcpPacket, for example)
I will suggest first turn this variable into a property with setter and getter. Then refactor your code to make sure all the places that directly write and read this variable are not changed to use the setter and getter of the property. Finally, you can set a conditional breakpoint in the setter of the property to halt the program when the property is set to -1. Then look at the call track to find out where does this happen.
I'm a little confused about when exactly my Property is being initialized.
Suppose I have a property declared like this:
private Dictionary<string, Dictionary<string,string>> MessageLookup
{
get
{
return messages ?? doSomething();
}
}
The doSomething method populates the messages Dictionary and returns it.
My question is, when is this code run?
If I place a breakpoint into the doSomething code, it isn't hit, but the MessageLookup property is holding data (this is the only place it is initialized) when I view it in the debugger.
Is this code run at construction? does the debugger run it automatically when I hover over the variable name? If so, why isn't the breakpoint hit?
That code is run whenever anyone refers to the property, and not before.
If you use the debugger, you'll see it because the debugger tries to fetch property values automatically (so you can see the state of the object). I don't know whether the debugger ignores breakpoints while it's evaluating properties for itself - that would explain everything.
Try running your code not in a debugger, and make some code access your property:
var lookup = someObject.MessageLookup;
Make doSomething() dump a stack trace and you'll see what's going on.
It is run when your property is first evaluated. No background stuff going on.
I'm guessing you're not seeing this because you use Quickwatch to inspect your object. At that point it will get executed and your breakpoint will be skipped.
Property getters (and ToString() for that matter) are assumed to be pure, which basically means evaluating it has no side effects. You should rewrite the code to adhere to that assumption or you'll face nasty consequences. If must use lazy initialization at access time, use a GetMessageLookup() method instead.
In Visual Studio, is there any way to make the debugger break whenever a certain file (or class) is entered? Please don't answer "just set a breakpoint at the beginning of every method" :)
I am using C#.
Macros can be your friend. Here is a macro that will add a breakpoint to every method in the current class (put the cursor somewhere in the class before running it).
Public Module ClassBreak
Public Sub BreakOnAnyMember()
Dim debugger As EnvDTE.Debugger = DTE.Debugger
Dim sel As EnvDTE.TextSelection = DTE.ActiveDocument.Selection
Dim editPoint As EnvDTE.EditPoint = sel.ActivePoint.CreateEditPoint()
Dim classElem As EnvDTE.CodeElement = editPoint.CodeElement(vsCMElement.vsCMElementClass)
If Not classElem Is Nothing Then
For Each member As EnvDTE.CodeElement In classElem.Children
If member.Kind = vsCMElement.vsCMElementFunction Then
debugger.Breakpoints.Add(member.FullName)
End If
Next
End If
End Sub
End Module
Edit: Updated to add breakpoint by function name, rather than file/line number. It 'feels' better and will be easier to recognise in the breakpoints window.
You could start by introducing some sort of Aspect-Oriented Programming - see for instance
this explanation - and then put a breakpoint in the single OnEnter method.
Depending on which AOP framework you choose, it'd require a little decoration in your code and introduce a little overhead (that you can remove later) but at least you won't need to set breakpoints everywhere. In some frameworks you might even be able to introduce it with no code change at all, just an XML file on the side?
Maybe you could use an AOP framework such as PostSharp to break into the debugger whenever a method is entered. Have a look at the very short tutorial on this page for an example, how you can log/trace whenever a method is entered.
Instead of logging, in your case you could put the Debugger.Break() statement into the OnEntry-handler. Although, the debugger would not stop in your methods, but in the OnEntry-handler (so I'm not sure if this really helps).
Here's a very basic sample:
The aspect class defines an OnEntry handler, which calls Debugger.Break():
[Serializable]
public sealed class DebugBreakAttribute : PostSharp.Laos.OnMethodBoundaryAspect
{
public DebugBreakAttribute() {}
public DebugBreakAttribute(string category) {}
public string Category { get { return "DebugBreak"; } }
public override void OnEntry(PostSharp.Laos.MethodExecutionEventArgs eventArgs)
{
base.OnEntry(eventArgs);
// debugger will break here. Press F10 to continue to the "real" method
System.Diagnostics.Debugger.Break();
}
}
I can then apply this aspect to my class, where I want the debugger to break whenever a method is called:
[DebugBreak("DebugBreak")]
public class MyClass
{
public MyClass()
{
// ...
}
public void Test()
{
// ...
}
}
Now if I build and run the application, the debugger will stop in the OnEntry() handler whenever one of the methods of MyClass is called. All I have to do then, is to press F10, and I'm in the method of MyClass.
Well, as everyone is saying, it involves setting a breakpoint at the beginning of every method. But you're not seeing the bigger picture.
For this to work at all, a breakpoint has to be set at the beginning of every method. Whether you do it manually, or the debugger does it automatically, those breakpoints must be set for this to work.
So, the question really becomes, "If there enough of a need for this functionality, that it is worth building into the debugger an automatic means of setting all those breakpoints?". And the answer is, "Not Really".
This feature is implemented in VS for native C++. crtl-B and specify the 'function' as "Classname::*", this sets a breakpoint at the beginning of every method on the class. The breakpoints set are grouped together in the breakpoints window (ctrl-alt-B) so they can be enabled, disabled, and removed as a group.
Sadly the macro is likely the best bet for managed code.
This works fine in WinDbg:
bm exename!CSomeClass::*
(Just to clarify, the above line sets a breakpoint on all functions in the class, just like the OP is asking for, without resorting to CRT hacking or macro silliness)
You could write a Visual Studio macro that obtained a list of all of the class methods (say, by reading the .map file produced alongside the executable and searching it for the proper symbol names (and then demangling those names)), and then used Breakpoints.add() to programmatically add breakpoints to those functions.
System.Diagnostics.Debugger.Break();
(at the beginning of every method)
No. Or rather, yes, but it involves setting a breakpoint at the beginning of every method.
Use Debugger.Break(); (from the System.Diagnostics namespace)
Put it at the top of each function you wish to have "broken"
void MyFunction()
{
Debugger.Break();
Console.WriteLine("More stuff...");
}
Isn't the simplest method to get closest to this to simply set a break point in the constructor (assuming you have only one - or each of them in the case of multiple constructors) ?
This will break into debugging when the class is first instantiated in the case of a non-static constructor, and in the case of a static constructor/class, you'll break into debugging as soon as Visual Studio decides to initialize your class.
This certainly prevents you from having to set a breakpoint in every method within the class.
Of course, you won't continue to break into debugging on subsequent re-entry to the class's code (assuming you're using the same instantiated object the next time around), however, if you re-instantiate a new object each time from within the calling code, you could simulate this.
However, in conventional terms, there's no simple way to set a single break point in one place (for example) and have it break into debugging every time a class's code (from whichever method) is entered (as far as I know).
Assuming that you're only interested in public methods i.e. when the class methods are called "from outside", I will plug Design by Contract once more.
You can get into the habit of writing your public functions like this:
public int Whatever(int blah, bool duh)
{
// INVARIANT (i)
// PRECONDITION CHECK (ii)
// BODY (iii)
// POSTCONDITION CHECK (iv)
// INVARIANT (v)
}
Then you can use the Invariant() function that you will call in (i) and set a breakpoint in it. Then inspect the call stack to know where you're coming from. Of course you will call it in (v), too; if you're really interested in only entry points, you could use a helper function to call Invariant from (i) and another one from (v).
Of course this is extra code but
It's useful code anyway, and the structure is boilerplate if you use Design by Contract.
Sometimes you want breakpoints to investigate some incorrect behaviour eg invalid object state, in that case invariants might be priceless.
For an object which is always valid, the Invariant() function just has a body that returns true. You can still put a breakpoint there.
It's just an idea, it admittedly has a footstep, so just consider it and use it if you like it.
Joel, the answer seems to be "no". There isn't a way without a breakpoint at every method.
To remove the breakpoints set by the accepted answer add another macro with the following code
Public Sub RemoveBreakOnAnyMember()
Dim debugger As EnvDTE.Debugger = DTE.Debugger
Dim bps As Breakpoints
bps = debugger.Breakpoints
If (bps.Count > 0) Then
Dim bp As Breakpoint
For Each bp In bps
Dim split As String() = bp.File.Split(New [Char]() {"\"c})
If (split.Length > 0) Then
Dim strName = split(split.Length - 1)
If (strName.Equals(DTE.ActiveDocument.Name)) Then
bp.Delete()
End If
End If
Next
End If
End Sub
Not that I'm aware of. The best you can do is to put a breakpoint in every method in the file or class. What are you trying to do? Are you trying to figure out what method is causing something to change? If so, perhaps a data breakpoint will be more appropriate.
You could write a wrapper method through which you make EVERY call in your app. Then you set a breakpoint in that single method. But... you'd be crazy to do such a thing.
You could put a memory break point on this, and set it to on read. I think there should be a read most of the time you call a member function. I'm not sure about static functions.
you can use the following macro:
#ifdef _DEBUG
#define DEBUG_METHOD(x) x DebugBreak();
#else
#define DEBUG_METHOD(x) x
#endif
#include <windows.h>
DEBUG_METHOD(int func(int arg) {)
return 0;
}
on function enter it will break into the debugger
IF this is C++ you are talking about, then you could probably get away with, (a hell of a lot of work) setting a break point in the preamble code in the CRT, or writing code that modifies the preamble code to stick INT 3's in there only for functions generated from the class in question... This, BTW, CAN be done at runtime... You'd have to have the PE file that's generated modify itself, possibly before relocation, to stick all the break's in there...
My only other suggestion would be to write a Macro that uses the predefined macro __FUNCTION__, in which you look for any function that's part of the class in question, and if necessary, stick a
__asm { int 3 }
in your macro to make VS break... This will prevent you from having to set break points at the start of every function, but you'd still have to stick a macro call, which is a lot better, if you ask me. I think I read somewhere on how you can define, or redefine the preamble code that's called per function.. I'll see what I can find.
I would think I similar hack could be used to detect which FILE you enter, but you STILL have to place YOUR function macro's all over your code, or it will never get called, and, well, that's pretty much what you didn't want to do.
If you are willing to use a macro then the accepted answer from this question
Should be trivially convertible to you needs by making the search function searching for methods, properties and constructors (as desired), there is also quite possibly a way to get the same information from the the ide/symbols which will be more stable (though perhaps a little more complex).
You can use Debugger.Launch() and Debugger.Break() in the assembly System.Diagnostics
Files have no existence at runtime (consider that partial classes are no different -- in terms of code -- from putting everything in a single file). Therefore a macro approach (or code in every method) is required.
To do the same with a type (which does exist at runtime) may be able to be done, but likely to be highly intrusive, creating more potential for heisenbugs. The "easiest" route to this is likely to be making use of .NET remoting's proxy infrastructure (see MOQ's implementation for an example of using transparent proxy).
Summary: use a macro, or select all followed by set breakpoint (ctrl-A, F9).
Mad method using reflection. See the documentation for MethodRental.SwapMethodBody for details. In pseudocode:
void SetBreakpointsForAllMethodsAndConstructorsInClass (string classname)
{
find type information for class classname
for each constructor and method
get MSIL bytes
prepend call to System.Diagnostics.Debugger.Break to MSIL bytes
fix up MSIL code (I'm not familiar with the MSIL spec. Generally, absolute jump targets need fixing up)
call SwapMethodBody with new MSIL
}
You can then pass in classname as a runtime argument (via the command line if you want) to set breakpoints on all methods and constructors of the given class.