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WinToolZone - Spelunking Microsoft Technologies
I work as a developer on the Common Language Runtime (CLR) team, specifically in the areas of exception handling and CLR hosting.

The information in this weblog is provided "AS IS" with no warranties, and confers no rights. This weblog does not represent the thoughts, intentions, plans or strategies of my employer. It is solely my opinion. Inappropriate comments will be deleted at the authors discretion. All code samples are provided "AS IS" without warranty of any kind, either express or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

Inside and Out... An attempt to understand technology better...

Surprisingly, enumerating AppDomains is not that straightforward. The System.AppDomain type does not expose functionality to enumerate them at all. The way to enumerate them will be to use the V1 Hosting interface, ICorRuntimeHost and then invoke the EnumDomains and NextDomain methods against it to get the list. If you are using CLR 2.0, you needn't worry as CLR 2.0 does implement the V1 interfaces as well.

Below is theĀ snippet that exemplifies the concept (note: AppDomains will only be enumerated in the current process - I will discuss AppDomain enumeration in remote processes later). You can download the source code (VS Solution) from

// EnumAppDomains.cpp : Defines the entry point for the console application.
#include "stdafx.h"
#include <windows.h>
#include "mscoree.h"

#import "C:\\Windows\\Microsoft.NET\\Framework\\v2.0.50727\\mscorlib.tlb" raw_interfaces_only

using namespace mscorlib; 

#define EXITONERROR(hr, mesg) \
if (FAILED(hr)) \
{ \
    printf("%s\n", mesg); \
    ExitProcess(1); \

#define SUCCESSFUL(hr) (SUCCEEDED(hr) && hr != S_FALSE) 
int _tmain(int argc, _TCHAR* argv[])
    ICorRuntimeHost * pV1HostPtr = NULL;
    HRESULT hr = CorBindToRuntimeEx(NULL,
                NULL, 0, 
                (LPVOID *)&pV1HostPtr);

    EXITONERROR(hr, "Unable to get ICorRuntimeHost*"); 
    // Start the runtime
    hr = pV1HostPtr->Start();
    EXITONERROR(hr, "Unable to start the runtime"); 
    // Enumerate the AppDomains
    hr = pV1HostPtr->EnumDomains(&adEnum);
    EXITONERROR(hr, "Unable to enumerate AppDomains");
    // Loop thru the domains
    IUnknown * pDomainUnk = NULL;
    hr = pV1HostPtr->NextDomain(adEnum, &pDomainUnk);
        // Got the IUnknown* to the AppDomain - convert it to AppDomain pointer
        _AppDomain * pCurDomain = NULL;
        hr = pDomainUnk->QueryInterface(__uuidof(_AppDomain), (VOID**)&pCurDomain);
        if (SUCCESSFUL(hr))
            // Display the name of the AppDomain
            BSTR str;
            if (SUCCESSFUL(pCurDomain->get_FriendlyName(&str)))
            wprintf(L"AppDomain: %s\n",str);
                printf("AppDomain: unable to get the name!\n");
        // Loop onto the next Domain
        hr = pV1HostPtr->NextDomain(adEnum, &pDomainUnk);

    // Stop the runtime
    if (pV1HostPtr)

    return 0;
Posted on Saturday, June 9, 2007 8:45 PM .NET Framework , Development , CLR | Back to top

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