Remoting and AppDomains

[Sam Martin]

Hi All,

I've got a problem where my application loads an assembly in the running
AppDomain when it shouldn't.

Ok, I've got a RemotingHost application that configs the remoting stuff and
then...
asks the user for a list of .net DLLs.
the app then copies a these assemblies to a cache folder along with my
RemotingClient app. Once copies i config a AppDomain setup and create a new
AppDomain.
Once created, i loop through the user chosen assemblies and load into the
AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.

The purpose is so that I can dynamically load and unload assemblies and
report on type information to my main app (in this case the RemotingHost).
Everything works fine in principal, however when I load the DLLs from my
cache folder the assembly is actually loaded in both AppDomains.

I know if i reference a type across AppDomain, it will cause the Framework
to load the assembly in the other AppDomain, but all i'm doing it is loading
it?

Any ideas? (please help:)

TIA
Sam Martin

(code sample below)

System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache");

// copy my RemotingClient. exe to the cache

// Set up the AppDomainSetup
AppDomainSetup setup = new AppDomainSetup( );
setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
setup.Configura tionFile = "";

// Set up the Evidence
System.Security .Policy.Evidenc e baseEvidence =
AppDomain.Curre ntDomain.Eviden ce;
System.Security .Policy.Evidenc e evidence = new
System.Security .Policy.Evidenc e(baseEvidence) ;
// evidence.AddAss embly("(some assembly)");

// Create the AppDomain
AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence, setup);

foreach(string an in this.listBoxAsm List.Items)
{

// copy the specified assembly to cache

string asmn = an.ToLower().Re place(".dll","" );

asmn = MyFuncToGetAsmD isplayName(an);
newDomain.Load( asmn);
}

newDomain.Execu teAssembly("Rem otingClient.exe );
AppDomain.Unloa d(newDomain);

[Ken Kolda]

If you're loading the assemblies using AppDomain.Load( ), that function
returns an Assembly object to the AppDomain of the caller, which causes the
caller to load the assembly as well. Read the "remarks" section of the
following documentation:

http://msdn.microsoft.com/library/en...asp?frame=true

One way to force an assembly to be loaded into another AppDomain without it
being loaded into the current one is to use the AppDomain.DoCal lback()
method to invoke a delegate that will run in the AppDomain in which you want
the assembly loaded. For example,

class Class1
{
[STAThread]
static void Main(string[] args)
{
AppDomainSetup s = new AppDomainSetup( );
s.ApplicationBa se =
AppDomain.Curre ntDomain.SetupI nformation.Appl icationBase;
AppDomain d = AppDomain.Creat eDomain("TestDo main",
AppDomain.Curre ntDomain.Eviden ce, s);

d.DoCallBack(ne w CrossAppDomainD elegate(DomainC all));
// ...
}

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(" MyAssembly");
}
}

The main thing to make sure of is that your delegate does not reference an
instance method of a MarshalByRef object, or else the assembly will be
loaded in the domain in which that object resides.

Hope that helps -
Ken

"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:eq******** *****@TK2MSFTNG P09.phx.gbl...

Hi All,

I've got a problem where my application loads an assembly in the running
AppDomain when it shouldn't.

Ok, I've got a RemotingHost application that configs the remoting stuff and then...
asks the user for a list of .net DLLs.
the app then copies a these assemblies to a cache folder along with my
RemotingClient app. Once copies i config a AppDomain setup and create a new AppDomain.
Once created, i loop through the user chosen assemblies and load into the
AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.

The purpose is so that I can dynamically load and unload assemblies and
report on type information to my main app (in this case the RemotingHost).
Everything works fine in principal, however when I load the DLLs from my
cache folder the assembly is actually loaded in both AppDomains.

I know if i reference a type across AppDomain, it will cause the Framework
to load the assembly in the other AppDomain, but all i'm doing it is loading it?

Any ideas? (please help:)

TIA
Sam Martin

(code sample below)

System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache");

// copy my RemotingClient. exe to the cache

// Set up the AppDomainSetup
AppDomainSetup setup = new AppDomainSetup( );
setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
setup.Configura tionFile = "";

// Set up the Evidence
System.Security .Policy.Evidenc e baseEvidence =
AppDomain.Curre ntDomain.Eviden ce;
System.Security .Policy.Evidenc e evidence = new
System.Security .Policy.Evidenc e(baseEvidence) ;
// evidence.AddAss embly("(some assembly)");

// Create the AppDomain
AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence, setup);

foreach(string an in this.listBoxAsm List.Items)
{

// copy the specified assembly to cache

string asmn = an.ToLower().Re place(".dll","" );

asmn = MyFuncToGetAsmD isplayName(an);
newDomain.Load( asmn);
}

newDomain.Execu teAssembly("Rem otingClient.exe );
AppDomain.Unloa d(newDomain);

[Sam Martin]

it all becomes clear.

thanks mate
"Ken Kolda" <ke*******@elli emae-nospamplease.co m> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

If you're loading the assemblies using AppDomain.Load( ), that function
returns an Assembly object to the AppDomain of the caller, which causes the caller to load the assembly as well. Read the "remarks" section of the
following documentation:

http://msdn.microsoft.com/library/en...asp?frame=true
One way to force an assembly to be loaded into another AppDomain without it being loaded into the current one is to use the AppDomain.DoCal lback()
method to invoke a delegate that will run in the AppDomain in which you want the assembly loaded. For example,

class Class1
{
[STAThread]
static void Main(string[] args)
{
AppDomainSetup s = new AppDomainSetup( );
s.ApplicationBa se =
AppDomain.Curre ntDomain.SetupI nformation.Appl icationBase;
AppDomain d = AppDomain.Creat eDomain("TestDo main",
AppDomain.Curre ntDomain.Eviden ce, s);

d.DoCallBack(ne w CrossAppDomainD elegate(DomainC all));
// ...
}

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(" MyAssembly");
}
}

The main thing to make sure of is that your delegate does not reference an
instance method of a MarshalByRef object, or else the assembly will be
loaded in the domain in which that object resides.

Hope that helps -
Ken

"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:eq******** *****@TK2MSFTNG P09.phx.gbl...

Hi All,

I've got a problem where my application loads an assembly in the running
AppDomain when it shouldn't.

Ok, I've got a RemotingHost application that configs the remoting stuff

and

then...
asks the user for a list of .net DLLs.
the app then copies a these assemblies to a cache folder along with my
RemotingClient app. Once copies i config a AppDomain setup and create a

new

AppDomain.
Once created, i loop through the user chosen assemblies and load into the AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.

The purpose is so that I can dynamically load and unload assemblies and
report on type information to my main app (in this case the RemotingHost). Everything works fine in principal, however when I load the DLLs from my
cache folder the assembly is actually loaded in both AppDomains.

I know if i reference a type across AppDomain, it will cause the Framework to load the assembly in the other AppDomain, but all i'm doing it is

loading

it?

Any ideas? (please help:)

TIA
Sam Martin

(code sample below)

System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache");

// copy my RemotingClient. exe to the cache

// Set up the AppDomainSetup
AppDomainSetup setup = new AppDomainSetup( );
setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
setup.Configura tionFile = "";

// Set up the Evidence
System.Security .Policy.Evidenc e baseEvidence =
AppDomain.Curre ntDomain.Eviden ce;
System.Security .Policy.Evidenc e evidence = new
System.Security .Policy.Evidenc e(baseEvidence) ;
// evidence.AddAss embly("(some assembly)");

// Create the AppDomain
AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence, setup);
foreach(string an in this.listBoxAsm List.Items)
{

// copy the specified assembly to cache

string asmn = an.ToLower().Re place(".dll","" );

asmn = MyFuncToGetAsmD isplayName(an);
newDomain.Load( asmn);
}

newDomain.Execu teAssembly("Rem otingClient.exe );
AppDomain.Unloa d(newDomain);

[Sam Martin]

ahh, one other thing. how would i specify which assembly to load from the
main appdomain
I could do something like, but even if libraryName is a static property of a
class in the main AppDomain, it's value would be null in the other AppDomain

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(l ibraryName);
}

you see what i mean, i need to say which assembly to load into the AppDomain
from the calling AppDomain without loading the spec'd assembly.

TIA

Sam Martin

"Ken Kolda" <ke*******@elli emae-nospamplease.co m> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

If you're loading the assemblies using AppDomain.Load( ), that function
returns an Assembly object to the AppDomain of the caller, which causes the caller to load the assembly as well. Read the "remarks" section of the
following documentation:

http://msdn.microsoft.com/library/en...asp?frame=true
One way to force an assembly to be loaded into another AppDomain without it being loaded into the current one is to use the AppDomain.DoCal lback()
method to invoke a delegate that will run in the AppDomain in which you want the assembly loaded. For example,

class Class1
{
[STAThread]
static void Main(string[] args)
{
AppDomainSetup s = new AppDomainSetup( );
s.ApplicationBa se =
AppDomain.Curre ntDomain.SetupI nformation.Appl icationBase;
AppDomain d = AppDomain.Creat eDomain("TestDo main",
AppDomain.Curre ntDomain.Eviden ce, s);

d.DoCallBack(ne w CrossAppDomainD elegate(DomainC all));
// ...
}

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(" MyAssembly");
}
}

The main thing to make sure of is that your delegate does not reference an
instance method of a MarshalByRef object, or else the assembly will be
loaded in the domain in which that object resides.

Hope that helps -
Ken

"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:eq******** *****@TK2MSFTNG P09.phx.gbl...

Hi All,

I've got a problem where my application loads an assembly in the running
AppDomain when it shouldn't.

Ok, I've got a RemotingHost application that configs the remoting stuff

and

then...
asks the user for a list of .net DLLs.
the app then copies a these assemblies to a cache folder along with my
RemotingClient app. Once copies i config a AppDomain setup and create a

new

AppDomain.
Once created, i loop through the user chosen assemblies and load into the AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.

The purpose is so that I can dynamically load and unload assemblies and
report on type information to my main app (in this case the RemotingHost). Everything works fine in principal, however when I load the DLLs from my
cache folder the assembly is actually loaded in both AppDomains.

I know if i reference a type across AppDomain, it will cause the Framework to load the assembly in the other AppDomain, but all i'm doing it is

loading

it?

Any ideas? (please help:)

TIA
Sam Martin

(code sample below)

System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache");

// copy my RemotingClient. exe to the cache

// Set up the AppDomainSetup
AppDomainSetup setup = new AppDomainSetup( );
setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
setup.Configura tionFile = "";

// Set up the Evidence
System.Security .Policy.Evidenc e baseEvidence =
AppDomain.Curre ntDomain.Eviden ce;
System.Security .Policy.Evidenc e evidence = new
System.Security .Policy.Evidenc e(baseEvidence) ;
// evidence.AddAss embly("(some assembly)");

// Create the AppDomain
AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence, setup);
foreach(string an in this.listBoxAsm List.Items)
{

// copy the specified assembly to cache

string asmn = an.ToLower().Re place(".dll","" );

asmn = MyFuncToGetAsmD isplayName(an);
newDomain.Load( asmn);
}

newDomain.Execu teAssembly("Rem otingClient.exe );
AppDomain.Unloa d(newDomain);

[Ken Kolda]

In this case, you probably want to do something a bit more sophisticated
using remoting. What I would do is create a class such as:

class AssemblyLoader : MarshalByRefObj ect
{
public void Load(string assemblyName)
{
AppDomain.Curre ntDomain.Load(a ssemblyName);
}
}

Then, from your main app domain, create an instance of this class in the new
app domain, e.g.

AssemblyLoader loader =
(AssemblyLoader ) newDomain.Creat eInstanceAndUnw rap("MyAssembly ",
"MyAssembly.Ass emblyLoader");
loader.Load("Pl uginAssembly");

The disadvantage of this technique is that your new AppDomain will have to
load the current assembly to get the definition of the AssemblyLoader class.

Hope that helps -
Ken
"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:%2******** *******@tk2msft ngp13.phx.gbl.. .

ahh, one other thing. how would i specify which assembly to load from the
main appdomain
I could do something like, but even if libraryName is a static property of a class in the main AppDomain, it's value would be null in the other AppDomain
public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(l ibraryName);
}

you see what i mean, i need to say which assembly to load into the AppDomain from the calling AppDomain without loading the spec'd assembly.

TIA

Sam Martin

"Ken Kolda" <ke*******@elli emae-nospamplease.co m> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

If you're loading the assemblies using AppDomain.Load( ), that function
returns an Assembly object to the AppDomain of the caller, which causes

the

caller to load the assembly as well. Read the "remarks" section of the
following documentation:

http://msdn.microsoft.com/library/en...asp?frame=true

One way to force an assembly to be loaded into another AppDomain without

it

being loaded into the current one is to use the AppDomain.DoCal lback()
method to invoke a delegate that will run in the AppDomain in which you

want

the assembly loaded. For example,

class Class1
{
[STAThread]
static void Main(string[] args)
{
AppDomainSetup s = new AppDomainSetup( );
s.ApplicationBa se =
AppDomain.Curre ntDomain.SetupI nformation.Appl icationBase;
AppDomain d = AppDomain.Creat eDomain("TestDo main",
AppDomain.Curre ntDomain.Eviden ce, s);

d.DoCallBack(ne w CrossAppDomainD elegate(DomainC all));
// ...
}

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(" MyAssembly");
}
}

The main thing to make sure of is that your delegate does not reference an

instance method of a MarshalByRef object, or else the assembly will be
loaded in the domain in which that object resides.

Hope that helps -
Ken

"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:eq******** *****@TK2MSFTNG P09.phx.gbl...

Hi All,

I've got a problem where my application loads an assembly in the running AppDomain when it shouldn't.

Ok, I've got a RemotingHost application that configs the remoting stuff

and

then...
asks the user for a list of .net DLLs.
the app then copies a these assemblies to a cache folder along with my
RemotingClient app. Once copies i config a AppDomain setup and create

a new

AppDomain.
Once created, i loop through the user chosen assemblies and load into

the AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.

The purpose is so that I can dynamically load and unload assemblies

and report on type information to my main app (in this case the

RemotingHost). Everything works fine in principal, however when I load the DLLs from my cache folder the assembly is actually loaded in both AppDomains.

I know if i reference a type across AppDomain, it will cause the Framework to load the assembly in the other AppDomain, but all i'm doing it is

loading

it?

Any ideas? (please help:)

TIA
Sam Martin

(code sample below)

System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache");
// copy my RemotingClient. exe to the cache

// Set up the AppDomainSetup
AppDomainSetup setup = new AppDomainSetup( );
setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
setup.Configura tionFile = "";

// Set up the Evidence
System.Security .Policy.Evidenc e baseEvidence =
AppDomain.Curre ntDomain.Eviden ce;
System.Security .Policy.Evidenc e evidence = new
System.Security .Policy.Evidenc e(baseEvidence) ;
// evidence.AddAss embly("(some assembly)");

// Create the AppDomain
AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence, setup);
foreach(string an in this.listBoxAsm List.Items)
{

// copy the specified assembly to cache

string asmn = an.ToLower().Re place(".dll","" );

asmn = MyFuncToGetAsmD isplayName(an);
newDomain.Load( asmn);
}

newDomain.Execu teAssembly("Rem otingClient.exe );
AppDomain.Unloa d(newDomain);

[Sam Martin]

yeah it does unfortunately.

almost had that working, but found the host (the assembly loader) kept being
loaded too - which i don't want really. otherwise i could have just loaded
everything together in a single appdomain using another appdomain to
effectively restart the app when i wanted to use a dif set of libraries.

shit, & all because you cannot unload an assembly from an appdomain.

thanks anyway

sam

"Ken Kolda" <ke*******@elli emae-nospamplease.co m> wrote in message
news:eh******** ******@TK2MSFTN GP11.phx.gbl...

In this case, you probably want to do something a bit more sophisticated
using remoting. What I would do is create a class such as:

class AssemblyLoader : MarshalByRefObj ect
{
public void Load(string assemblyName)
{
AppDomain.Curre ntDomain.Load(a ssemblyName);
}
}

Then, from your main app domain, create an instance of this class in the new app domain, e.g.

AssemblyLoader loader =
(AssemblyLoader ) newDomain.Creat eInstanceAndUnw rap("MyAssembly ",
"MyAssembly.Ass emblyLoader");
loader.Load("Pl uginAssembly");

The disadvantage of this technique is that your new AppDomain will have to
load the current assembly to get the definition of the AssemblyLoader class.
Hope that helps -
Ken
"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:%2******** *******@tk2msft ngp13.phx.gbl.. .

ahh, one other thing. how would i specify which assembly to load from the

main appdomain
I could do something like, but even if libraryName is a static property of

a

class in the main AppDomain, it's value would be null in the other AppDomain

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(l ibraryName);
}

you see what i mean, i need to say which assembly to load into the

AppDomain

from the calling AppDomain without loading the spec'd assembly.

TIA

Sam Martin

"Ken Kolda" <ke*******@elli emae-nospamplease.co m> wrote in message
news:%2******** ********@tk2msf tngp13.phx.gbl. ..

If you're loading the assemblies using AppDomain.Load( ), that function
returns an Assembly object to the AppDomain of the caller, which causes the

caller to load the assembly as well. Read the "remarks" section of the
following documentation:

http://msdn.microsoft.com/library/en...asp?frame=true
One way to force an assembly to be loaded into another AppDomain without

it

being loaded into the current one is to use the AppDomain.DoCal lback()
method to invoke a delegate that will run in the AppDomain in which

you want

the assembly loaded. For example,

class Class1
{
[STAThread]
static void Main(string[] args)
{
AppDomainSetup s = new AppDomainSetup( );
s.ApplicationBa se =
AppDomain.Curre ntDomain.SetupI nformation.Appl icationBase;
AppDomain d = AppDomain.Creat eDomain("TestDo main",
AppDomain.Curre ntDomain.Eviden ce, s);

d.DoCallBack(ne w CrossAppDomainD elegate(DomainC all));
// ...
}

public static void DomainCall()
{
AppDomain.Curre ntDomain.Load(" MyAssembly");
}
}

The main thing to make sure of is that your delegate does not

reference an instance method of a MarshalByRef object, or else the assembly will be
loaded in the domain in which that object resides.

Hope that helps -
Ken

"Sam Martin" <sa*********@ya hoo.co.uk> wrote in message
news:eq******** *****@TK2MSFTNG P09.phx.gbl...
> Hi All,
>
> I've got a problem where my application loads an assembly in the running > AppDomain when it shouldn't.
>
> Ok, I've got a RemotingHost application that configs the remoting stuff and
> then...
> asks the user for a list of .net DLLs.
> the app then copies a these assemblies to a cache folder along with

my > RemotingClient app. Once copies i config a AppDomain setup and

create a new
> AppDomain.
> Once created, i loop through the user chosen assemblies and load

into the

> AppDomain. I then AppDomain.Execu teAssembly my RemotingClient.
>
> The purpose is so that I can dynamically load and unload assemblies

and > report on type information to my main app (in this case the

RemotingHost).

> Everything works fine in principal, however when I load the DLLs

from my > cache folder the assembly is actually loaded in both AppDomains.
>
> I know if i reference a type across AppDomain, it will cause the

Framework

> to load the assembly in the other AppDomain, but all i'm doing it is
loading
> it?
>
> Any ideas? (please help:)
>
> TIA
> Sam Martin
>
> (code sample below)
>
> System.IO.Direc tory.CreateDire ctory(Applicati on.StartupPath+ "\\cache"); >
> // copy my RemotingClient. exe to the cache
>
> // Set up the AppDomainSetup
> AppDomainSetup setup = new AppDomainSetup( );
> setup.Applicati onBase = Application.Sta rtupPath+"\\cac he\\";
> setup.Configura tionFile = "";
>
> // Set up the Evidence
> System.Security .Policy.Evidenc e baseEvidence =
> AppDomain.Curre ntDomain.Eviden ce;
> System.Security .Policy.Evidenc e evidence = new
> System.Security .Policy.Evidenc e(baseEvidence) ;
> // evidence.AddAss embly("(some assembly)");
>
> // Create the AppDomain
> AppDomain newDomain = AppDomain.Creat eDomain("temp", evidence,

setup);

>
> foreach(string an in this.listBoxAsm List.Items)
> {
>
> // copy the specified assembly to cache
>
> string asmn = an.ToLower().Re place(".dll","" );
>
> asmn = MyFuncToGetAsmD isplayName(an);
> newDomain.Load( asmn);
> }
>
> newDomain.Execu teAssembly("Rem otingClient.exe );
> AppDomain.Unloa d(newDomain);
>
>