I am working with the Windows 8 developer build. I am attempting to create a basic dependency property. I've used them before in WPF and Silverlight. However, I'm not trying to create one in WinRT without any luck.
public static DependencyProperty GPAProperty = DependencyProperty.Register("GPA", "double", "MyNamespace.MyClass", new PropertyMetadata(0));
public double GPA
{
get { return (double)GetValue(GPAProperty); }
set { SetValue(GPAProperty, value); }
}
When I run my code, I get a runtime exception when the app first starts that says:
A first chance exception of type 'System.TypeInitializationException' occurred in mscorlib.dll
My question is, does this look right? I keep thinking I'm overlooking something. But it all looks correct to me.
You need to change double to Double...
Related
When running the following snippet of VSTO code I get a COM exception
if (param.SelectedShape.Type != MsoShapeType.msoPlaceholder) { //Stuff is happening }
The exception occurs when trying to read the Type property of SelectedShape.
We have been running with this code in PowerPoint (Office 365 ProPlus) for a long time, but somewhere between build 9126.2210 (works) and build 9330.2087 (doesn't work) it broke.
When looking through the release notes it doesn't seem like anything has been changed that should be related to this. What could have been changed?
You might try to use the call in a try/catch block like here:
try
{
if (param.SelectedShape.Type != MsoShapeType.msoPlaceholder)
{
// Stuff is happening
}
}
catch (COMException)
{
// Add logging here
}
This is a workaround. Of course, Microsoft should fix the problem.
When I create a new project, I get a strange behavior for unhandled exceptions. This is how I can reproduce the problem:
1) create a new Windows Forms Application (C#, .NET Framework 4, VS2010)
2) add the following code to the Form1_Load handler:
int vara = 5, varb = 0;
int varc = vara / varb;
int vard = 7;
I would expect that VS breaks and shows an unhandled exception message at the second line. However, what happens is that the third line is just skipped without any message and the application keeps running.
I don't have this problem with my existing C# projects. So I guess that my new projects are created with some strange default settings.
Does anyone have an idea what's wrong with my project???
I tried checking the boxes in Debug->Exceptions. But then executions breaks even if I handle the exception in a try-catch block; which is also not what I want. If I remember correctly, there was a column called "unhandled exceptions" or something like this in this dialog box, which would do excatly what I want. But in my projects there is only one column ("Thrown").
This is a nasty problem induced by the wow64 emulation layer that allows 32-bit code to run on the 64-bit version of Windows 7. It swallows exceptions in the code that runs in response to a notification generated by the 64-bit window manager, like the Load event. Preventing the debugger from seeing it and stepping in. This problem is hard to fix, the Windows and DevDiv groups at Microsoft are pointing fingers back and forth. DevDiv can't do anything about it, Windows thinks it is the correct and documented behavior, mysterious as that sounds.
It is certainly documented but just about nobody understands the consequences or thinks it is reasonable behavior. Especially not when the window procedure is hidden from view of course, like it is in any project that uses wrapper classes to hide the window plumbing. Like any Winforms, WPF or MFC app. Underlying issue is Microsoft could not figure out how to flow exceptions from 32-bit code back to the 64-bit code that triggered the notification back to 32-bit code that tries to handle or debug the exception.
It is only a problem with a debugger attached, your code will bomb as usual without one.
Project > Properties > Build tab > Platform target = AnyCPU and untick Prefer 32-bit. Your app will now run as a 64-bit process, eliminating the wow64 failure mode. Some consequences, it disables Edit + Continue for VS versions prior to VS2013 and might not always be possible when you have a dependency on 32-bit code.
Other possible workarounds:
Debug > Exceptions > tick the Thrown box for CLR exceptions to force the debugger to stop at the line of code that throws the exception.
Write try/catch in the Load event handler and failfast in the catch block.
Use Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException) in the Main() method so that the exception trap in the message loop isn't disabled in debug mode. This however makes all unhandled exceptions hard to debug, the ThreadException event is pretty useless.
Consider if your code really belongs in the Load event handler. It is very rare to need it, it is however very popular in VB.NET and a swan song because it is the default event and a double-click trivially adds the event handler. You only ever really need Load when you are interested in the actual window size after user preferences and autoscaling is applied. Everything else belongs in the constructor.
Update to Windows 8 or later, they have this wow64 problem solved.
In my experience, I only see this issue when I'm running with a debugger attached. The application behaves the same when run standalone: the exception is not swallowed.
With the introduction of KB976038, you can make this work as you'd expect again. I never installed the hotfix, so I'm assuming it came as part of Win7 SP1.
This was mentioned in this post:
The case of the disappearing OnLoad exception – user-mode callback exceptions in x64
Here's some code that will enable the hotfix:
public static class Kernel32
{
public const uint PROCESS_CALLBACK_FILTER_ENABLED = 0x1;
[DllImport("Kernel32.dll")]
public static extern bool SetProcessUserModeExceptionPolicy(UInt32 dwFlags);
[DllImport("Kernel32.dll")]
public static extern bool GetProcessUserModeExceptionPolicy(out UInt32 lpFlags);
public static void DisableUMCallbackFilter() {
uint flags;
GetProcessUserModeExceptionPolicy(out flags);
flags &= ~PROCESS_CALLBACK_FILTER_ENABLED;
SetProcessUserModeExceptionPolicy(flags);
}
}
Call it at the beginning of your application:
[STAThread]
static void Main()
{
Kernel32.DisableUMCallbackFilter();
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
I've confirmed (with the the simple example shown below) that this works, just as you'd expect.
protected override void OnLoad(EventArgs e) {
throw new Exception("BOOM"); // This will now get caught.
}
So, what I don't understand, is why it was previously impossible for the debugger to handle crossing kernel-mode stack frames, but with this hotfix, they somehow figured it out.
As Hans mentions, compile the application and run the exe without a debugger attached.
For me the problem was changing a Class property name that a BindingSource control was bound to. Running without the IDE I was able to see the error:
Cannot bind to the property or column SendWithoutProofReading on the
DataSource. Parameter name: dataMember
Fixing the BindingSource control to bind to the updated property name resolved the problem:
I'm using WPF and ran into this same problem. I had tried Hans 1-3 suggestions already, but didn't like them because studio wouldn't stop at where the error was (so I couldn't view my variables and see what was the problem).
So I tried Hans' 4th suggestion. I was suprised at how much of my code could be moved to the MainWindow constructor without any issue. Not sure why I got in the habit of putting so much logic in the Load event, but apparently much of it can be done in the ctor.
However, this had the same problem as 1-3. Errors that occur during the ctor for WPF get wrapped into a generic Xaml exception. (an inner exception has the real error, but again I wanted studio to just break at the actual trouble spot).
What ended up working for me was to create a thread, sleep 50ms, dispatch back to main thread and do what I need...
void Window_Loaded(object sender, RoutedEventArgs e)
{
new Thread(() =>
{
Thread.Sleep(50);
CrossThread(() => { OnWindowLoaded(); });
}).Start();
}
void CrossThread(Action a)
{
this.Dispatcher.BeginInvoke(a);
}
void OnWindowLoaded()
{
...do my thing...
This way studio would break right where an uncaught exception occurs.
A simple work-around could be if you can move your init code to another event like as Form_Shown which called later than Form_Load, and use a flag to run startup code at first form shown:
bool firstLoad = true; //flag to detect first form_shown
private void Form1_Load(object sender, EventArgs e)
{
//firstLoad = true;
//dowork(); //not execute initialization code here (postpone it to form_shown)
}
private void Form1_Shown(object sender, EventArgs e)
{
if (firstLoad) //simulate Form-Load
{
firstLoad = false;
dowork();
}
}
void dowork()
{
var f = File.OpenRead(#"D:\NoSuchFile756.123"); //this cause an exception!
}
When I create a new project, I get a strange behavior for unhandled exceptions. This is how I can reproduce the problem:
1) create a new Windows Forms Application (C#, .NET Framework 4, VS2010)
2) add the following code to the Form1_Load handler:
int vara = 5, varb = 0;
int varc = vara / varb;
int vard = 7;
I would expect that VS breaks and shows an unhandled exception message at the second line. However, what happens is that the third line is just skipped without any message and the application keeps running.
I don't have this problem with my existing C# projects. So I guess that my new projects are created with some strange default settings.
Does anyone have an idea what's wrong with my project???
I tried checking the boxes in Debug->Exceptions. But then executions breaks even if I handle the exception in a try-catch block; which is also not what I want. If I remember correctly, there was a column called "unhandled exceptions" or something like this in this dialog box, which would do excatly what I want. But in my projects there is only one column ("Thrown").
This is a nasty problem induced by the wow64 emulation layer that allows 32-bit code to run on the 64-bit version of Windows 7. It swallows exceptions in the code that runs in response to a notification generated by the 64-bit window manager, like the Load event. Preventing the debugger from seeing it and stepping in. This problem is hard to fix, the Windows and DevDiv groups at Microsoft are pointing fingers back and forth. DevDiv can't do anything about it, Windows thinks it is the correct and documented behavior, mysterious as that sounds.
It is certainly documented but just about nobody understands the consequences or thinks it is reasonable behavior. Especially not when the window procedure is hidden from view of course, like it is in any project that uses wrapper classes to hide the window plumbing. Like any Winforms, WPF or MFC app. Underlying issue is Microsoft could not figure out how to flow exceptions from 32-bit code back to the 64-bit code that triggered the notification back to 32-bit code that tries to handle or debug the exception.
It is only a problem with a debugger attached, your code will bomb as usual without one.
Project > Properties > Build tab > Platform target = AnyCPU and untick Prefer 32-bit. Your app will now run as a 64-bit process, eliminating the wow64 failure mode. Some consequences, it disables Edit + Continue for VS versions prior to VS2013 and might not always be possible when you have a dependency on 32-bit code.
Other possible workarounds:
Debug > Exceptions > tick the Thrown box for CLR exceptions to force the debugger to stop at the line of code that throws the exception.
Write try/catch in the Load event handler and failfast in the catch block.
Use Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException) in the Main() method so that the exception trap in the message loop isn't disabled in debug mode. This however makes all unhandled exceptions hard to debug, the ThreadException event is pretty useless.
Consider if your code really belongs in the Load event handler. It is very rare to need it, it is however very popular in VB.NET and a swan song because it is the default event and a double-click trivially adds the event handler. You only ever really need Load when you are interested in the actual window size after user preferences and autoscaling is applied. Everything else belongs in the constructor.
Update to Windows 8 or later, they have this wow64 problem solved.
In my experience, I only see this issue when I'm running with a debugger attached. The application behaves the same when run standalone: the exception is not swallowed.
With the introduction of KB976038, you can make this work as you'd expect again. I never installed the hotfix, so I'm assuming it came as part of Win7 SP1.
This was mentioned in this post:
The case of the disappearing OnLoad exception – user-mode callback exceptions in x64
Here's some code that will enable the hotfix:
public static class Kernel32
{
public const uint PROCESS_CALLBACK_FILTER_ENABLED = 0x1;
[DllImport("Kernel32.dll")]
public static extern bool SetProcessUserModeExceptionPolicy(UInt32 dwFlags);
[DllImport("Kernel32.dll")]
public static extern bool GetProcessUserModeExceptionPolicy(out UInt32 lpFlags);
public static void DisableUMCallbackFilter() {
uint flags;
GetProcessUserModeExceptionPolicy(out flags);
flags &= ~PROCESS_CALLBACK_FILTER_ENABLED;
SetProcessUserModeExceptionPolicy(flags);
}
}
Call it at the beginning of your application:
[STAThread]
static void Main()
{
Kernel32.DisableUMCallbackFilter();
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
I've confirmed (with the the simple example shown below) that this works, just as you'd expect.
protected override void OnLoad(EventArgs e) {
throw new Exception("BOOM"); // This will now get caught.
}
So, what I don't understand, is why it was previously impossible for the debugger to handle crossing kernel-mode stack frames, but with this hotfix, they somehow figured it out.
As Hans mentions, compile the application and run the exe without a debugger attached.
For me the problem was changing a Class property name that a BindingSource control was bound to. Running without the IDE I was able to see the error:
Cannot bind to the property or column SendWithoutProofReading on the
DataSource. Parameter name: dataMember
Fixing the BindingSource control to bind to the updated property name resolved the problem:
I'm using WPF and ran into this same problem. I had tried Hans 1-3 suggestions already, but didn't like them because studio wouldn't stop at where the error was (so I couldn't view my variables and see what was the problem).
So I tried Hans' 4th suggestion. I was suprised at how much of my code could be moved to the MainWindow constructor without any issue. Not sure why I got in the habit of putting so much logic in the Load event, but apparently much of it can be done in the ctor.
However, this had the same problem as 1-3. Errors that occur during the ctor for WPF get wrapped into a generic Xaml exception. (an inner exception has the real error, but again I wanted studio to just break at the actual trouble spot).
What ended up working for me was to create a thread, sleep 50ms, dispatch back to main thread and do what I need...
void Window_Loaded(object sender, RoutedEventArgs e)
{
new Thread(() =>
{
Thread.Sleep(50);
CrossThread(() => { OnWindowLoaded(); });
}).Start();
}
void CrossThread(Action a)
{
this.Dispatcher.BeginInvoke(a);
}
void OnWindowLoaded()
{
...do my thing...
This way studio would break right where an uncaught exception occurs.
A simple work-around could be if you can move your init code to another event like as Form_Shown which called later than Form_Load, and use a flag to run startup code at first form shown:
bool firstLoad = true; //flag to detect first form_shown
private void Form1_Load(object sender, EventArgs e)
{
//firstLoad = true;
//dowork(); //not execute initialization code here (postpone it to form_shown)
}
private void Form1_Shown(object sender, EventArgs e)
{
if (firstLoad) //simulate Form-Load
{
firstLoad = false;
dowork();
}
}
void dowork()
{
var f = File.OpenRead(#"D:\NoSuchFile756.123"); //this cause an exception!
}
I'm getting this error when I deploy a VB.NET application and for the life of me I cannot figure out why.
I do not get this error when I run the app from the IDE and the test machine I am deploying it to has a similar configuration to the dev machine...Windows 7 & .NET 3.51 SP1 and 4.0.
The app bombs out when the main form is loaded after logging in. I've narrowed it down to the main form because if I load another form from login and then open the main form, this happens.
Linked below is a screenshot of the stack trace.
Any ideas? I'm really lost here.
Thanks.
I do not see a way for ShapeCollection.Dispose() to throw that exception. Although it is manipulating a List<> that can indeed throw that exception, the code should not trigger it:
private void Dispose(bool disposing)
{
if (!this.m_Disposed && disposing)
{
for (int i = this.m_Shapes.Count - 1; i >= 0; i--)
{
this.m_Shapes[i].Dispose();
}
this.m_Shapes.Clear();
this.m_Shapes = null;
}
this.m_Disposed = true;
}
Well, this is from the PowerPacks version that I have. There have been a couple of versions of it floating around, it used to be distributed separately. Make sure you didn't accidentally deploy an old version.
Working with Linq2Sql as a driver for a Wcf Service. Lets go bottom up....
Down at the bottom, we have the method that hits Linq2Sql...
public virtual void UpdateCmsDealer(CmsDealer currentCmsDealer)
{
this.Context.CmsDealers.Attach(currentCmsDealer,
this.ChangeSet.GetOriginal(currentCmsDealer));
}
That gets used by my Wcf service as such...
public bool UpdateDealer(CmsDealer dealer)
{
try
{
domainservice.UpdateCmsDealer(dealer);
return true;
}
catch
{
return false;
}
}
And called from my Wpf client code thus (pseudocode below)...
[...pull the coreDealer object from Wcf, it is a CmsDealer...]
[...update the coreDealer object with new data, not touchign the relation fields...]
try
{
contextCore.UpdateDealer(coreDealer);
}
catch (Exception ex)
{
[...handle the error...]
}
Now, the CmsDealer type has >1< foriegn key relationship, it uses a "StateId" field to link to a CmsItemStates table. So yes, in the above coreDealer.StateId is filled, and I can access data on coreDealer.CmsItemState.Title does show me the tile of the appropriate state.
Now, here is the thing... if you comment out the line...
domainservice.UpdateCmsDealer(dealer);
In the Wcf service it STILL bombs with the exception below, which indicates to me that it isn't really a Linq2Sql problem but rather a Linq2Sql over Wcf issue.
"System.Data.Linq.ForeignKeyReferenceAlreadyHasValueException was unhandled by user code
Message="Operation is not valid due to the current state of the object."
InnerException is NULL. The end result of it all when it bubles up to the error handler (the Catch ex bloc) the exception message will complain about the deserializer. When I can snatch a debug, the actual code throwing the error is this snippit from the CmsDealer model code built by Linq2Sql.
[Column(Storage="_StateId", DbType="UniqueIdentifier NOT NULL")]
public System.Guid StateId
{
get
{
return this._StateId;
}
set
{
if ((this._StateId != value))
{
if (this._CmsItemState.HasLoadedOrAssignedValue)
{
throw new System.Data.Linq.ForeignKeyReferenceAlreadyHasValueException();
}
this.OnStateIdChanging(value);
this.SendPropertyChanging();
this._StateId = value;
this.SendPropertyChanged("StateId");
this.OnStateIdChanged();
}
}
}
In short, it would appear that some stuff is happening "under the covers" which is fine but the documentation is nonexistent. Hell googleing for "ForeignKeyReferenceAlreadyHasValueException" turns up almost nothing :)
I would prefer to continue working with the Linq2Sql objects directly over Wcf. I could, if needed, create a flat proxy class that had no association, ship it up the wire to Wcf then use it as a data source for a server side update... but that seems like a lot of effort when clearly this is an intended scenario... right?
Thanks!
The default serializer will first set the State, which will set the StateId. After that it will try to set the serialized StateId and then the exception is thrown.
The problem is that you did not specify that you want you classes to be decorated with the DataContract attribute.
Go to the properties of your LinqToSqlGenerator and set the Serialization Mode to Unidirectional
This will cause the tool to add the DataMember attribute to the required properties and you will see that the StateId will not be a DataMember since it will be automatically set when the State Property is set while deserializing.
The error is likely due to something changing the fk value after it has been initially set - are you sure you don't have some custom initialisation code somewhere that might be initially setting the value?
You could breakpoint the set (where it's throwing), and step out each time it's set (skipping the exception if you need to) which should hopefully point you in the right direction.