Prevent app from crashing without giving info when dll is missing

Question

If some dll required by my VB.NET program is missing, when I run it, it crashes with the typical Windows error message, and does not provide any information about the error.

So, I thought of validating that all dependencies are satisfied before doing anything. But this is not trivial because I have unmanaged and runtime dependencies. So, before delving into that, is there some CLR setting, or some easier solution for this issue?

Answer 1

It was really easy (avoiding Windows' boilerplate message, that is). You just have to make your application handle the UnhandledException event.

For a VB.NET app windows forms like mine, that meant going to the project properties, Application tab and clicking the View Application events button.

That opened the (hidden by default) ApplicationEvents.vb file. I added some code:

Namespace My

    ' The following events are available for MyApplication:
    ' 
    ' Startup: Raised when the application starts, before the startup form is created.
    ' Shutdown: Raised after all application forms are closed.  This event is not raised if the application terminates abnormally.
    ' UnhandledException: Raised if the application encounters an unhandled exception.
    ' StartupNextInstance: Raised when launching a single-instance application and the application is already active. 
    ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected.
    Partial Friend Class MyApplication

        Private Sub MyApplication_UnhandledException(ByVal sender As Object, _
                                                     ByVal e As Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs _
                                                     ) Handles Me.UnhandledException
            MessageBox.Show("Application crashed due to the following unhandled exception. " + e.Exception.ToString())
        End Sub

    End Class    

End Namespace

Now, if I'm missing some dll, I get its name, if it's managed or mixed, in the exception message. If the missing dll is unmanaged, I get just the name of the mixed assembly which needs it. But that's ok with me; throwing the mixed assembly on Depends.exe quickly reveals the offending unmanaged assembly.