Visual Studio compiles WPF application twice during build

I have a WPF app in VS2008 that compiles twice during the build. The two CSC command lines are similar but with some differences. The first CSC command line does not have an /resource options, the second has two /resource options on the command line.

The second CSC command line has these additional arguments:

/resource:"obj\Debug AutoCAD\VisualApp.g.resources" /resource:"obj\Debug AutoCAD\CAP.Visual.Properties.Resources.resources"

I hate to post such a huge ugly compiler output but here are both command lines.

2>c:\WINDOWS\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /platform:x86 /errorreport:prompt /warn:4 /define:DEBUG;TRACE /reference:..\BIN\RELEASE\FOO.Base.dll /reference:..\BIN\RELEASE\FOO.CAPArchiveHandler.dll /reference:..\BIN\RELEASE\FOO.CAPDOM.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\PresentationCore.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\PresentationFramework.dll" /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll" /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll" /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\System.Runtime.Serialization.dll" /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.Docking.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.Navigation.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\UIAutomationProvider.dll" /reference:c:\project\FooStudio\BIN\DEBUGCAD\VS-3DEngine-Wrapper.dll /reference:c:\project\FooStudio\BIN\DEBUGCAD\VisualServiceClient.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\WindowsBase.dll" /debug+ /debug:full /filealign:512 /out:"obj\Debug AutoCAD\VisualApp.exe"                                                                                                                             /target:winexe App.xaml.cs MainWindow.xaml.cs CameraAndLightingControl.xaml.cs CameraAndLightingViewModel.cs MainWindowViewModel.cs Properties\AssemblyInfo.cs Properties\Resources.Designer.cs Properties\Settings.Designer.cs ScenarioToolsWindow.xaml.cs SceneGraph.cs ScenePart.cs ToolWindow.xaml.cs "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\CameraAndLightingControl.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\MainWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\ScenarioToolsWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\ToolWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\App.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\GeneratedInternalTypeHelper.g.cs"
2>Done building project "0ye0i4wb.tmp_proj".
2>c:\WINDOWS\Microsoft.NET\Framework\v3.5\Csc.exe /noconfig /nowarn:1701,1702 /platform:x86 /errorreport:prompt /warn:4 /define:DEBUG;TRACE /reference:..\BIN\RELEASE\FOO.Base.dll /reference:..\BIN\RELEASE\FOO.CAPArchiveHandler.dll /reference:..\BIN\RELEASE\FOO.CAPDOM.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\PresentationCore.dll" /reference:"C:\Program Files\Referen开发者_开发问答ce Assemblies\Microsoft\Framework\v3.0\PresentationFramework.dll" /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Core.dll" /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Data.DataSetExtensions.dll" /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Data.dll /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\System.Runtime.Serialization.dll" /reference:c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\System.Xml.dll /reference:"c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\System.Xml.Linq.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.Docking.dll" /reference:"C:\Program Files\Telerik\RadControls for WPF Q1 2010\Binaries\WPF\Telerik.Windows.Controls.Navigation.dll" /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\UIAutomationProvider.dll" /reference:c:\project\FooStudio\BIN\DEBUGCAD\VS-3DEngine-Wrapper.dll /reference:c:\project\FooStudio\BIN\DEBUGCAD\VisualServiceClient.dll /reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\WindowsBase.dll" /debug+ /debug:full /filealign:512 /out:"obj\Debug AutoCAD\VisualApp.exe" /resource:"obj\Debug AutoCAD\VisualApp.g.resources" /resource:"obj\Debug AutoCAD\FOO.Visual.Properties.Resources.resources" /target:winexe App.xaml.cs MainWindow.xaml.cs CameraAndLightingControl.xaml.cs CameraAndLightingViewModel.cs MainWindowViewModel.cs Properties\AssemblyInfo.cs Properties\Resources.Designer.cs Properties\Settings.Designer.cs ScenarioToolsWindow.xaml.cs SceneGraph.cs ScenePart.cs ToolWindow.xaml.cs "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\CameraAndLightingControl.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\MainWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\ScenarioToolsWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\ToolWindow.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\App.g.cs" "c:\project\FooStudio\VisualApp\obj\Debug AutoCAD\GeneratedInternalTypeHelper.g.cs"

Any idea what could possibly cause this? I think this is causing a problem I posted about earlier today.

I've noticed that it does not always occur with WPF projects, only if in XAML you refer to the namespace of the assembly the XAML file belongs to! It makes sense that you would need two compile steps in this case, because for the XAML->BAML compile step it needs to refer to the assembly, so it first needs to build the assembly before it can incorporate elements from the assembly.

1. create a WPF application called WpfApplication1

2. add a UserControl called UserControl1

3. in MainWindow.xaml, add "xmlns:my=clr-namespace:WpfApplication1" and insert the UserContro1l in the XAML by adding to the

4. compile and see in the output that there are two compile steps, the first being a temporary project.

(see also http://social.msdn.microsoft.com/Forums/en/msbuild/thread/3a52c962-187d-4701-9967-e0d25eb3b897 about a problem that the temporary project does not read the .csproj.user file)

Much of the reasoning for the two stage compiles is described here:

Building a WPF Application (WPF)

http://msdn.microsoft.com/en-us/library/aa970678(v=vs.110).aspx

Not all XAML pages are compiled at during pass 1 of markup compilation. XAML files that have locally defined type references (references to types defined in code elsewhere in the same project) are exempt from compilation at this time.

Unfortunately the two-phase compilation of a large project can have a significant performance impact on the edit/build/debug workflow for software development. I guess it makes sense to keep non-xaml out of a WPF/xaml project as much as possible so there isn't a bunch of duplicated work that needs to be done by csc.exe. Otherwise it feels like Visual Studio 2013 builds are being executed very slowly (and it almost makes one consider going back to Windows Forms, VB 6 or even FoxPro).