Application works when started locally or from mapped network drive but not from UNC path

Question

Short story

I have a weird problem and couldn't find any solution for it across internet.

This is probably not important for a problem but I prefer to mention that I had two separate projects and decided to combine them into one solution. Both projects were/are simple winform application. They worked separately after compiling: directly in Visual Studio during debugging (no matter in debug or release mode), locally outside debugger and after copying them into some folder on local network.

However after merging them, one of the application stopped working when it is started from the network.

Stop working means?

I attached debugger to the already running process and found out that:

1. Code in frmMain.Designer.vb in Partial Class frmMain in Private Sub InitializeComponent() works properly. This is checked by making a breakpoint at the begin of Sub and going step-by-step through the code until End Sub .
2. Code in frmMain.vb in Public Class frmMain in Private Sub frmMain_Load(sender As Object, e As EventArgs) Handles MyBase.Load is not triggered. After going out from InitializeComponent() (point 1) code does not enter frmMain_Load . Main form is shown on the screen with all controls but not initialized/cleaned, without icon etc.
3. Clicking some buttons on main form allows me to open child forms but they are also not initialized/cleaned.

4. Closing child form by clicking on "X" doesn't close the form (normally does). Clicking on cmdClose button on the same child form closes the form. Button has DialogResult property set to Cancel . Form itself has CancelButton property set to cmdClose . Pressing ESC also closes the form.

    Private Sub cmdClose_Click(sender As Object, e As EventArgs) Handles cmdClose.Click Me.Dispose() End Sub 

5. Closing the main form (no matter if by "X", cmdClose button or ESC ) hangs up the application.

    Private Sub cmdClose_Click(sender As Object, e As EventArgs) Handles cmdClose.Click Me.Close() End Sub 

6. If I open Windows Explorer and go to the final location of application on shared network drive starting from the mapped drive Y:\\folder and start application from there - it works.

7. However if choose the same final destination through \\\\server\\share-name\\folder and start application from there - it doesn't work.
8. Point 6 and 7 acts the same if application is started by a shortcut on desktop and in this shortcut target path to application is defined in one of the two methods.

Windows 7, .Net Framework 4.5.

Do you have any clue how to solve it and where the bug is?

Answer 1

Explanation of error

I decided to extract the icon from application executable instead of resource like it was before to avoid adding two times the same icon file to the executable: first as an application icon which is added in Project/Properties/Application/Icon and second as an form icon added in Project/Properties/Resources.

The problem is if in any place in code (in my example in Private Sub form_Load(sender As Object, e As EventArgs) Handles MyBase.Load ) you add

Me.Icon = Icon.ExtractAssociatedIcon(Assembly.GetExecutingAssembly().Location)

it will not work with UNC paths returning

System.ArgumentException
The filePath does not indicate a valid file or the filePath indicates a Universal Naming Convention (UNC) path.

Error occurs in runtime after form closing. Method

Assembly.GetExecutingAssembly().Location

returns correct path (as string for example \\\\server\\share-name\\folder ) but method

Public Shared Function ExtractAssociatedIcon(filePath As String) As Icon

does not accept UNC path.

Solution

To solve this issue 2 clumsy solutions are proposed here and here .