I have a solution with two projects: a WPF sample application called "WPFSample" and a class library project called "ReferencedAssembly". "WPFSample" references "ReferencedAssembly".
The project "ReferencedAssembly" contains a couple of classes. Every class has its own namespace, i.e. "MyClassLibrary" or "MyClassLibrary.MyOtherTypes". A sample class with the namespace "MyClassLibrary" is called "Movie".
Now I want to map the .NET namespace to the XAML namespace using the URL "http://schemas.emmbee.de/". For this purpose I added the following lines to AssemblyInfo.vb in the "WPFSample" project and build it afterwards:
Imports System.Windows.Markup
<Assembly: XmlnsPrefix("http://schemas.emmbee.de/", "ra")>
<Assembly: XmlnsDefinition("http://schemas.emmbee.de/", "ReferencedAssembly.MyClassLibrary")>
<Assembly: XmlnsDefinition("http://schemas.emmbee.de/", "ReferencedAssembly.MyClassLibrary.MyOtherTypes")>
In XAML I add the namespace definition like this:
<xmlns:ra="http://schemas.emmbee.de">
If I want to use the "Movie" class with
<ra:Movie/>
I receive the error, that the class "Movie" doesn't exists in namespace "http://schemas.emmbee.de".
If I instead add a namespace definition in this way:
<xmlns:ra="clr-namespace:ReferencedAssembly.MyClassLibrary;assembly=ReferencedAssembly">
all works fine.
What is wrong with the XmlnsDefinition?
I found it out.The Namespace mappings
Imports System.Windows.Markup
<Assembly: XmlnsPrefix("http://schemas.emmbee.de/", "ra")>
<Assembly: XmlnsDefinition("http://schemas.emmbee.de/", "ReferencedAssembly.MyClassLibrary")>
<Assembly: XmlnsDefinition("http://schemas.emmbee.de/", "ReferencedAssembly.MyClassLibrary.MyOtherTypes")>
must be included in the "AssemblyInfo.vb" in the assembly "ReferencedAssembly", not in the assembly "WPFSample".
I have decided to learn ReactiveUI after seeing what can be done with it, but my enthusiasm has been broken at the first attempt to run a simple project. I have recreated the example from this article, using reactiveui-winforms.Net40 version 6.5.0 from NuGet. Everything compiles ok, but i get an exception during runtime at the following line
var OKCmdObs = this.WhenAny(vm => vm.EnteredText,
s => !string.IsNullOrWhiteSpace(s.Value));
System.InvalidOperationException occurred
HResult=-2146233079
Message=The current thread has no Dispatcher associated with it.
Source=System.Reactive.Windows.Threading
StackTrace:
at System.Reactive.Concurrency.DispatcherScheduler.get_Current()
at ReactiveUI.PlatformRegistrations.<>c.<Register>b__0_7() in C:\workspace\git-perso\ReactiveUI\ReactiveUI\Platform\Registrations.cs:line 75
InnerException:
Does anyone have any idea of what's happening ?
The mentioned article does not have the compiled project available for download, and i didn't find any complete "Hello-World" project for reactiveui-winforms.
My test project can be downloaded here.
In Visual Studio, if i Continue(F5), another exception occures :
System.NullReferenceException occurred
HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=ReactiveUI
StackTrace:
at ReactiveUI.IROObservableForProperty.<>c__DisplayClass1_0.<GetNotificationForProperty>b__6(IReactivePropertyChangedEventArgs`1 x) in C:\workspace\git-perso\ReactiveUI\ReactiveUI\IROObservableForProperty.cs:line 44
InnerException:
If i continue to hit F5 i get :
System.Exception was unhandled by user code
HResult=-2146233088
Message=An OnError occurred on an object (usually ObservableAsPropertyHelper) that would break a binding or command. To prevent this, Subscribe to the ThrownExceptions property of your objects
Source=ReactiveUI
This exception is caused because RxUI always tries to initialize for WPF, even though (because you're also using the winforms package) it'll override this setting with a Winforms-based scheduler right after.
It should be harmless though, as it's catched and ignored. You're probably hitting it within VS ?
When editing a XAML file I noticed the following error:
System.ObjectDisposedException occurred
Message=Cannot access a disposed object.
Object name: 'FileCodeModel'.
To debug this I ran another instance of Visual Studios and "Debug-> Attach to Process" to the instance of visual studio where the exception was shown.
I was able to catch the exception in the new Instances that started that is attached to the process. I catch the following exception:
System.ObjectDisposedException occurred
Message=Cannot access a disposed object.
Object name: 'FileCodeModel'.
Source=Microsoft.VisualStudio.CSharp.Services.Language
ObjectName=FileCodeModel
StackTrace:
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CFileCodeModel.GetCompilation(Boolean fBlockForParses)
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CPartialTypeCollection.EnumerateParts()
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CPartialTypeCollection.get_Count()
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CSlowSnapshot..ctor(CodeElements collection)
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CPartialTypeCollection.CreateSnapshot()
at Microsoft.VisualStudio.CSharp.Services.Language.CodeModel.CCollectionBase.GetEnumerator()
at EnvDTE.CodeElements.GetEnumerator()
at MS.Internal.VSSymbols.SymbolProvider.GetProperties(String fullName, Boolean isTypeDefinition, Boolean useCodeModel)
at Microsoft.Xaml.Symbols.IXamlSymbols.GetProperties(String typeName, Boolean isTypeDefinition, Boolean useCodeModel)
at MS.Internal.Design.Markup.HostedType.BuildProperties(Boolean useCodeModel)
InnerException:
Anybody ever run into this exception in your XAML, and what do you do to fix it.
Are you running a XAML beautifier? - I've had something similar with an extension that cleans XAML up.
This happened to me when I manually grouped a .xaml.cs and .xaml file by editing the .csproj file. To fix this I:
Moved .xaml file to different folder.
Opened up solution.
Removed .xaml from project.
Re-created .xaml file in Visual Studio.
Copied the contents of my original .xaml into the newly created .xaml.
After following these steps I no longer got that error message.
I want to run my wpf application "A" from another assembly "B".
I use the following code:
static void main()
{
var app = new A.App();
app.InitializeComponent();
app.Run();
}
when i run my app I got the following error:
Cannot convert string '/Resources/icon.gif' in attribute 'Icon' to object of type 'System.Windows.Media.ImageSource'. Cannot locate resource 'resources/icon.gif'. Error at object 'MainWindow' in markup file 'A;component/shell/shellview.xaml'.
How can I transfer from B images and resources info to A?
Thanks!
Are you using the Pack URI?
You can use the pack URI syntax to access resources embedded in other assemblies. The following example demonstrates the basic pack URI syntax for accessing embedded resources in other assemblies:
pack://application:,,,/;component//
Thus, if you wanted to locate a file named myPic.bmp in the folder myFolder in another assembly named myAssembly, you would use the following pack URI:
Pack://application:,,,/myAssembly;component/myFolder/myPic.bmp
As with other pack URIs, if the embedded file does not exist within a folder, the folder is omitted in the URI.
TRy using something like this:
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary
Source="CustomControls.Controls;component\Themes/...."
/>
</ResourceDictionary.MergedDictionaries>
Today I had the same problem, and I solved it by putting just:
Source="../../Resources/name.jpg"
While trying to answer a question in the vicinity 'Unit Testing WPF Bindings' I had the following niggling question..
What's the best way to find if you have WPF Data Binding wiring setup incorrectly (or you just broke something that was wired up correctly) ?
Although the unit-testing approach seems to be like Joel's 'ripping off your arm to remove a splinter'.. I am looking around for easier less Overhead ways to detect this.
Everyone seems to have committed themselves to data binding in a big way with WPF.. and it does have its merits.
In .NET 3.5 it was introduced a new way to specifically output tracing information about specific data bindings.
This is done through the new System.Diagnostics.PresentationTraceSources.TraceLevel attached property that you can apply to any binding or data provider. Here is an example:
<Window x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:diag="clr-namespace:System.Diagnostics;assembly=WindowsBase"
Title="Debug Binding Sample"
Height="300"
Width="300">
<StackPanel>
<TextBox Name="txtInput" />
<Label>
<Label.Content>
<Binding ElementName="txtInput"
Path="Text"
diag:PresentationTraceSources.TraceLevel="High" />
</Label.Content>
</Label>
</StackPanel>
</Window>
This will put trace information for just that particular binding in Visual Studio's Output Window, without any tracing configuration required.
Best I could find...
How can I debug WPF Bindings? by Beatriz Stollnitz
Since everyone can't always keep one eye on the Output Window looking for Binding errors, I loved Option#2. Which is add this to your App.Config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.diagnostics>
<sources>
<source name="System.Windows.Data" switchName="SourceSwitch" >
<listeners>
<add name="textListener" />
</listeners>
</source>
</sources>
<switches>
<add name="SourceSwitch" value="All" />
</switches>
<sharedListeners>
<add name="textListener"
type="System.Diagnostics.TextWriterTraceListener"
initializeData="GraveOfBindErrors.txt" />
</sharedListeners>
<trace autoflush="true" indentsize="4"></trace>
</system.diagnostics>
</configuration>
Pair that up with a good regex scan script to extract out relevant info, that you can run occasionally on the GraveOfBindErrors.txt in your output folder
System.Windows.Data Error: 35 : BindingExpression path error: 'MyProperty' property not found on 'object' ''MyWindow' (Name='')'. BindingExpression:Path=MyProperty; DataItem='MyWindow' (Name=''); target element is 'TextBox' (Name='txtValue2'); target property is 'Text' (type 'String')
I use the solution presented here to turn binding errors into native Exceptions: http://www.jasonbock.net/jb/Default.aspx?blog=entry.0f221e047de740ee90722b248933a28d
However, a normal scenario in WPF bindings is to throw exceptions in case the user input cannot be converted to the target type (for instance, a TextBox bound to a integer field; the input of a non-numeric string results in a FormatException, the input of number that is too large results in an OverflowException). A similar case is when the Setter of the source property throws an exception.
The WPF way of handling this is via ValidatesOnExceptions=true and ValidationExceptionRule to signal the user the supplied input is not correct (using the exception message).
However, these exception are also send to the output window and thus 'caught' by the BindingListener, resulting in an error...clearly not the behaviour you'd want.
Therefore, I expanded the BindingListener class to NOT throw an Exception in these cases:
private static readonly IList<string> m_MessagesToIgnore =
new List<String>()
{
//Windows.Data.Error 7
//Binding transfer from target to source failed because of an exception
//Normal WPF Scenario, requires ValidatesOnExceptions / ExceptionValidationRule
//To cope with these kind of errors
"ConvertBack cannot convert value",
//Windows.Data.Error 8
//Binding transfer from target to source failed because of an exception
//Normal WPF Scenario, requires ValidatesOnExceptions / ExceptionValidationRule
//To cope with these kind of errors
"Cannot save value from target back to source"
};
Modified lines in public override void WriteLine(string message):
....
if (this.InformationPropertyCount == 0)
{
//Only treat message as an exception if it is not to be ignored
if (!m_MessagesToIgnore.Any(
x => this.Message.StartsWith(x, StringComparison.InvariantCultureIgnoreCase)))
{
PresentationTraceSources.DataBindingSource.Listeners.Remove(this);
throw new BindingException(this.Message,
new BindingExceptionInformation(this.Callstack,
System.DateTime.Parse(this.DateTime),
this.LogicalOperationStack, int.Parse(this.ProcessId),
int.Parse(this.ThreadId), long.Parse(this.Timestamp)));
}
else
{
//Ignore message, reset values
this.IsFirstWrite = true;
this.DetermineInformationPropertyCount();
}
}
}
You can use the trigger debugging feature of WPF Inspector. Just download the tool from codeplex and attach it to your running app. It also shows binding errors on the bottom of the window.
Very useful tool!
Here's a useful technique for debugging/tracing triggers effectively. It allows you to log all trigger actions along with the element being acted upon:
http://www.wpfmentor.com/2009/01/how-to-debug-triggers-using-trigger.html
This was very helpful to us but I wanted to add to those who find this useful that there is a utility that Microsoft provides with the sdk to read this file.
Found here: http://msdn.microsoft.com/en-us/library/ms732023.aspx
To open a trace file
1.Start Service Trace Viewer by using a command window to navigate to your
WCF installation location (C:\Program
Files\Microsoft
SDKs\Windows\v6.0\Bin), and then type
SvcTraceViewer.exe. (although we found ours in \v7.0\Bin)
Note: The Service Trace Viewer tool
can associate with two file types:
.svclog and .stvproj. You can use two
parameters in command line to register
and unregister the file extensions.
/register: register the association of
file extensions ".svclog" and
".stvproj" with SvcTraceViewer.exe
/unregister: unregister the
association of file extensions
".svclog" and ".stvproj" with
SvcTraceViewer.exe
1.When Service Trace Viewer starts, click File and then point to Open.
Navigate to the location where your
trace files are stored.
2.Double-click the trace file that you want to open.
Note: Press SHIFT while clicking
multiple trace files to select and
open them simultaneously. Service
Trace Viewer merges the content of all
files and presents one view. For
example, you can open trace files of
both client and service. This is
useful when you have enabled message
logging and activity propagation in
configuration. In this way, you can
examine message exchange between
client and service. You can also drag
multiple files into the viewer, or use
the Project tab. See the Managing
Project section for more details.
3.To add additional trace files to the collection that is open, click File
and then point to Add. In the window
that opens, navigate to the location
of the trace files and double-click
the file you want to add.
Also, as for the filtering of the log file, we found these this link extremely helpful:
http://msdn.microsoft.com/en-us/library/ms751526.aspx
For anyone like me looking for a pure programmatic way of enabling all WPF Tracing at a given Trace Level, here is a piece of code that does it. For reference, it's based on this article: Trace sources in WPF.
It doesn't requires a change in the app.config file, and it does not require to change the registry either.
This is how I use it, in some startup place (App, etc.):
....
#if DEBUG
WpfUtilities.SetTracing();
#endif
....
And here is the utility code (by default it sends all Warning to the Default Trace Listener):
public static void SetTracing()
{
SetTracing(SourceLevels.Warning, null);
}
public static void SetTracing(SourceLevels levels, TraceListener listener)
{
if (listener == null)
{
listener = new DefaultTraceListener();
}
// enable WPF tracing
PresentationTraceSources.Refresh();
// enable all WPF Trace sources (change this if you only want DataBindingSource)
foreach (PropertyInfo pi in typeof(PresentationTraceSources).GetProperties(BindingFlags.Static | BindingFlags.Public))
{
if (typeof(TraceSource).IsAssignableFrom(pi.PropertyType))
{
TraceSource ts = (TraceSource)pi.GetValue(null, null);
ts.Listeners.Add(listener);
ts.Switch.Level = levels;
}
}
}
My suggestion at 2021:
The Best way is to use Benoit Blanchon small library from Nuget
His original post at here: https://stackoverflow.com/a/19610384/6296708
His GitHub link and more info about how to use it + Nuget command: https://github.com/bblanchon/WpfBindingErrors
Its features (until now!):
throw exception on binding errors (+ line number)
If source Variable throw any exceptions, this library will catch it and show it.
Unit Test supports too!
Happy Coding!