WPF Type initialization Exception in C#

Question

I have someone else's WPF-based .NET 3.5 app that I'm attempting to update to .NET 4.5. The code ran fine under .NET 3.5, and I'm running Visual Studio 2013 Express on Windows 7. The update seemed to go well and the code compiles fine, but when I try to run the app I get the following exception.

An unhandled exception of type 'System.TypeInitializationException' occurred in PresentationFramework.dll

Additional information: The type initializer for 'System.Windows.Application' threw an exception.

Here are the last few steps in the stacktrace.

PresentationFramework.dll!System.Windows.Windows.Application()
MiniMon.exe!MiniMon.App.App()
MiniMon.exe!MiniMon.App.Main()

Here's the app.xaml file.

<Application x:Class="MiniMon.App"
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 StartupUri="Window1.xaml">
<Application.Resources>
</Application.Resources>
</Application>

I can download a sample WPF app (WPFCalculator) and it runs fine, so I tried stripping the one I'm updating down to just what was in the sample app. I also tried adding a breakpoint at the entry point of the code in app.xaml.cs, but the exception is thrown even before that code is executed. As a last resort I tried running the app on Windows 8, but got the same error.

How can this problem be resolved?

You might check all your references (including .net framework) and make sure you aren't still referencing any 3.5 framework assemblies. — JMarsch
– JMarsch, Commented Feb 28, 2014 at 0:10
@DragomirRăzvan Here is the code for app.xaml.cs. I'm not quite sure why the original author didn't add the standard initialization code, but I've tried adding it and still get the same error. using System; using System.Collections.Generic; using System.Configuration; using System.Data; using System.Linq; using System.Windows; namespace MiniMon { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { } } — wrightjm
– wrightjm, Commented Feb 28, 2014 at 1:21
According to the documentation for the System.TypeInitializationException: "When a class initializer fails to initialize a type, a TypeInitializationException is created and passed a reference to the exception thrown by the type's class initializer. The InnerException property of TypeInitializationException holds the underlying exception." Have you looked at the inner exception? — Paulo Morgado
– Paulo Morgado, Commented Feb 28, 2014 at 23:21

StayOnTarget · Accepted Answer · 2024-08-23 13:56:56Z

30

I solve this problem by moving startup section in app.config to the last part before </configuration>, startup section must be the last part in app.config, like this:

    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
</configuration>

edited Aug 23, 2024 at 13:56

StayOnTarget

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answered Sep 7, 2014 at 8:10

Reza M.A

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2 Comments

mwilczynski Over a year ago

Mess in App.config was preventing me from launching the WPF app too.

BrainSlugs83 Over a year ago

I had the same exact error as OP, and it ended up being caused by a syntax error in App.Config. Seems like the exception that's thrown is definitely caused by something being wrong with App.Config.

Guruprasad J Rao · Accepted Answer · 2016-09-05 18:38:44Z

9

Late to the party, but found this reason in my case. I had added a key-value pair with appSettings in app.config as in

<appSettings>
    <add key="EncryKey" value="MyKey"/>
</appSettings>

before <configSections>. Upon digging in the internet, I came to know that, <configSections> had to be at the top of the root, soon after <configuration> and rest of the orders are irrelevant. Moving appSettings below <configSections> helped me fix this issue.

answered Sep 5, 2016 at 18:38

Guruprasad J Rao

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1 Comment

Onno Over a year ago

This was the answer that did it for me. Thnx!

usefulBee · Accepted Answer · 2016-04-28 19:38:09Z

6

Digging Deeper into the Exception Details down to the last InnerException, and I found this:

"Only one <configSections> element allowed per config file and if present must be the first child of the root <configuration> element"

Move configSections to the beginning

answered Apr 28, 2016 at 19:38

usefulBee

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Comments

Shaaak · Accepted Answer · 2014-02-28 05:29:15Z

3

One (not very educational) workaround would be to start a new 4.5 project, and copy-paste the relevant pieces of code from the old one.

answered Feb 28, 2014 at 5:29

Shaaak

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1 Comment

wrightjm Over a year ago

As you mentioned @shahar, this certainly wasn't an idea solution, but it's the one I ended up having to go with. The application ran without any code changes once I copied everything over to the new .NET 4.5 project.

Akshay Kumar Sharma · Accepted Answer · 2017-08-18 03:34:44Z

1

<connectionStrings> tag should come after <configSections> and <startup> section. This made my code work.

answered Aug 18, 2017 at 3:34

Akshay Kumar Sharma

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Comments

mathielo · Accepted Answer · 2016-07-05 12:14:46Z

0

Check the spellings of connectionStrings,connectionString="" if used! 'S' should be capital ..XML is case sensitive :)

edited Jul 5, 2016 at 12:14

mathielo

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answered Jul 5, 2016 at 11:54

David_Shervin

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Comments

Mbithy Mbithy · Accepted Answer · 2017-04-08 08:03:14Z

0

Check app.config file make sure that you don't have configurations to lib(s) that you no longer use or you have removed from the project

answered Apr 8, 2017 at 8:03

Mbithy Mbithy

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Comments

Lee Song · Accepted Answer · 2017-09-15 06:47:52Z

0

I replaced the depreciated Configuration library and also removed entity framework so I can't track what's wrong at all, but rebuilding helped me. Solution to Rebuild your App.Config file.

answered Sep 15, 2017 at 6:47

Lee Song

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