How to set "Break on All Exceptions", from a Package

Question

I want to make an extension to quickly toggle breaking on CLR exceptions in debugger. I have made tried several approaches, neither of which is satisfactory. Here is what I have already tried: `ExceptionSettings.SetBreakWhenThrown` (MSDN) This is extremely slow (see this Connect issue). I have tried approaches from question "Toggle “Break when an exception is thrown.” using macro or keyboard shortcut" and neither seem to work reliably: in most cases only top level checkbox gets set, and it does not actually break on exceptions when debugging. Call `DTE.ExecuteCommand("Debug.Exceptions")` to show the window, and call `SetWindowsHookEx` (MSDN) just before that to intercept it before it appears (so that there is no flash to the user). This seems possible as I was able to intercept the message and get `HWND`. But it seems hacky and window is not that easy to manipulate properly (it has some weird combination of `SysListView32` with custom checkboxes and `SysTreeView32`). So I am leaving i…

Accepted Answer

The automation interfaces are out of the question. In an attempt to improve performance using them, I created a cache from exception group to `ExceptionSettings` object and exception name to the `ExceptionSetting` object. This allowed me to bypass `ExceptionSettings.Item` for rapid lookup of individual exceptions for calling `SetBreakWhenThrown`, but unfortunately the internal implementation of `SetBreakWhenThrown` includes a call to validate the arguments, which in turn triggers an internal enumeration process that plagues this entire approach. The cache is about 4 times faster than code not using a macro, but we're still talking about code that will hang the IDE for several minutes...

NOTE: The instructions below were only tested so far with Visual Studio 2012.

Stepping through `SetBreakWhenThrown` in disassembly view revealed that the critical internal call (after validation) is `sdm::CDebugManager::SetException`. It turns out that the shell debugger (`SVsShellDebugger` service which you cast to `IVsDebugger`) implements `IDebuggerInternal` which provides access to the current `IDebugSession3`. This property was non-null after I opened a solution but before I started debugging.

```
IDebuggerInternal debugger = Package.GetGlobalService(typeof(SVsShellDebugger)) as IDebuggerInternal;
IDebugSession3 session = debugger != null ? debugger.CurrentSession : null;
```

Note: The `IDebuggerInternal` interface is defined in:

```
Microsoft.VisualStudio.Debugger.Interop.Internal, Version=11.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
```

Using information returned by `EnumSetExceptions`, I created a structure that successfully alters the settings for a CLR exception! Call `IDebugSession3.SetException` to enable the debugger halting when the exception is thrown.

```
EXCEPTION_INFO[] exceptionInfo =
{
    new EXCEPTION_INFO()
    {
        bstrExceptionName = typeof(NullReferenceException).FullName,
        bstrProgramName = null,
        dwCode = 0,
        pProgram = null,
        guidType = VSConstants.DebugEnginesGuids.ManagedOnly_guid,
        dwState = enum_EXCEPTION_STATE.EXCEPTION_STOP_FIRST_CHANCE
            | enum_EXCEPTION_STATE.EXCEPTION_STOP_SECOND_CHANCE
            | enum_EXCEPTION_STATE.EXCEPTION_JUST_MY_CODE_SUPPORTED
            | enum_EXCEPTION_STATE.EXCEPTION_STOP_USER_FIRST_CHANCE
            | enum_EXCEPTION_STATE.EXCEPTION_STOP_USER_UNCAUGHT
    }
};
hr = session.SetException(exceptionInfo);
```

To disable the debugger halting, use `IDebugSession3.RemoveSetException` instead.

How to set "Break on All Exceptions", from a Package

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