TypeInitializationException thrown for Program class

Question

My Windows Forms application was working earlier, however suddenly it stopped working. I am getting following exception:

Answer 1

Make sure you are not missing any dependency DLLs. In my case, a DLL I was referencing had a dependency on another DLL.

If this is what happened, look at the "Inner Exception" property and then you will see a better error message. In my case, it said "Cannot find xxx.dll"

Answer 2

After trying all of the answers listed here, I have a new one:

The type initializer for 'MyLibrary' threw an exception.

If you see something like the below in the InnerException(s)..........

"Could not load file or assembly 'log4net, Version=1.2.13.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a' or one of its dependencies. The system cannot find the file specified.":"log4net, Version=1.2.13.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a"

In my case, my directory had the correct version dll. (log4net.dll in this case).

And then ... the issue was found. Assembly redirects in the app.config.

:(

Since I had the correct version, I removed all my redirects. Your situation may be different.

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="log4net" publicKeyToken="b32731d11ce58905" />
        <codeBase version="1.2.9.0" href="log4netv1.2.9.0\log4net.dll" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="log4net" publicKeyToken="1b44e1d426115821" />
        <codeBase version="1.2.10.0" href="log4netv1.2.10.0\log4net.dll" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="log4net" publicKeyToken="669e0ddf0bb1aa2a" />
        <codeBase version="1.2.13.0" href="log4netv1.2.13.0\log4net.dll" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

Answer 3

This is one weird issue I had to deal with for the last 2 hours. I solved it by removing the static from the lists I created.

private static readonly List<Person> someList = GlobalConfiguration.Connection.PopulateList();

with this one:

private readonly List<Person> someList = GlobalConfiguration.Connection.PopulateList();

Hope it helps and you don't have to spend two hours to find out the bug...

Answer 4

In my case the reason was, that <configSections> wasn't first one in config file.

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

Move the configSections element to the top in your config file.

Hope it helps to someone.

Answer 5

Another possible reason: the app.config has duplicate sections.

Answer 6

So: either one of the field-initializers, or the static constructor, for Program - is failing. Find out why. Note: the InnerException has the actual exception that was raised, but basicaly: just debug the field initializers and static constructor. So look inside the Program class for either:

static SomeType someField = /* some non-trivial expression or method call */ 

or:

static Program() {
    // stuff
}