I have an App.config fiel in which i defined some binding information.
I want this information in some external file so that user can change it whenever required.
Anyone have an idea about how to implement it?
Thanks in advance
Assuming we're talking about assembly binding redirects...
The runtime is going to use your App.exe.config file to locate the binding redirects. I don't believe you can do anything about this in a normal managed application because the runtime is already initialized by the time you can run any code.
If you had an unmanaged "shim" (an exe in C++ for example) that used the CLR hosting API's, you can tell it the name of a config file to use when you set up the AppDomain. But I don't believe you can make your binding redirects separate from the main application config.
Your only other option would be to handle the AppDomain.AssemblyResolve event to handle binding failures. But this is potentially expensive as the runtime will exhaust all of its options for probing the assembly before raising this event.
Related
I need to write a program that uses some COM objects, accessed from the python comtypes package. I use the clsid and/or progid to create and use them. These objects are provided by a third party, and normally they are installed with a normal installer (setup.exe or MSI file).
Let's suppose that these DLL files have a license that allows me to ship them together with my program. Is it possible to load these DLL files into memory, and use them from a portable app without actually registering them? Or alternatively, can I register them from my program?
A related question is this: how to determine the chain of DLL files that are needed to create a given COM object? (Other than trial and error.)
Background: in reality, there are multiple libs and the main problem is that I do not want the users to run 4 different installers before they can start the actual program. That would be too difficult for an average user.
You're asking a lot of questions here. There are a lot of ways to accomplish what you're trying to accomplish, and it's hard to answer such a broad set of questions. If you have specific questions on how to do a specific thing, please start new posts for those.
That said, I will try to give you some information to help you figure out what you need/want to do.
Can you use a COM DLL without registering it?
Yes. There are several ways, depending on the needs of the COM DLL and the platform you're using. However, some options won't always work, and other options are very challenging.
DllGetClassObject - In some cases, depending on the COM object you're trying to load, you can just load the DLL, call the DllGetClassObject function directly, and use the returned IClassFactory to create your object. This is the easiest way -- if it works. If the class you create requires that the DLL be registered (maybe it does a CoCreateInstance internally, or maybe it needs proxy support), this won't work for you. To determine if this will work, it's either trial-and-error, or you have to ask the developer of the COM DLL.
Registration-free COM - This is how it's done in .NET. I'm not sure if you can do anything like this easily in Python.
CoRegisterClassObject - If you are going to create your own registration-free COM implementation, this function is going to be critical. I believe this is a fundamental implementation detail for Microsoft's registration-free COM. However, be aware that this would be a very challenging thing to do, and it would require a very good understanding of COM.
Can you register a COM DLL from your program?
Yes. There are a few ways. However, you are likely to run into security issues here -- typically, COM components register themselves in HKEY_LOCAL_MACHINE, and you typically need admin rights to write here. Some COM components/installers are designed to register themselves in HKEY_CURRENT_USER, which would get around the security thing. However, you may have no control over where a component registers itself, and even if you do, registering in HKEY_CURRENT_USER isn't a perfect solution.
regsvr32.exe - One option is to programmatically invoke regsvr32.exe on the DLL.
DllRegisterServer or DllInstall - If a COM DLL can be registered with regsvr32.exe, then it has at least one of these functions exported. You can load the DLL manually and call these functions just like regsvr32.exe does. DllInstall is less common than DllRegisterServer. If DllInstall is present, it may give you the option of installing in HKEY_CURRENT_USER. If not, you have to just do whatever DllRegisterServer does, since there are no options you can provide to that function.
Write the registry values yourself -- If you can figure out all the registry settings that are needed, there's nothing stopping you from putting them into the registry manually. This would get around the HKEY_LOCAL_MACHINE/HKEY_CURRENT_USER issue -- you can write them wherever you like (but HKEY_LOCAL_MACHINE still probably requires admin rights).
regedit.exe - Another way to write the registry values yourself is to store them in a .reg file and call regedit.exe to merge them.
How do you determine dependencies of a DLL?
Ideally, the developer of that DLL knows and can tell you. That's the only way that's truly fool-proof.
For COM dependencies, it may be impossible to figure this out any other way than asking the developer or trial-and-error. This is because a COM dependency may exist simply because some code in the DLL just calls CoCreateInstance to create some third-party COM object, and since this is something that is only expressed in source code, there is no metadata on the DLL that will help you find these dependencies.
The above is also true for any dynamically-loaded dependencies. For example, if some code just calls LoadLibrary directly, there is no way for you to determine the dependency from the outside.
For statically-loaded dependencies, you can use tools like Dependency Walker. Note that a lot of the dependencies you will see are system dependencies -- you don't want to include, for example, user32.dll and kernel32.dll because these are installed with Windows.
How do you install third-party dependencies?
If you know exactly what files to write, where to write them and what registry settings (etc) need to be applied, you can do all of that yourself. For some dependencies, it can be easier to just include the third-party installer in your installer and just execute it silently. Many installers support a silent mode for just this reason. A good example of this is the Visual C++ runtime (msvcrt*.dll) -- many applications need this dependency, and many installers just include Microsoft's installer as a part of their distribution, and the primary installer just calls the secondary installers silently.
I have two ocx files which i registered on my computer using regsvr32. I use them in my visual studio project by adding a reference to the COM objects, to the project.
The problem is that when I attempt to add these to a SharePoint project, when I attempt to invoke the COM object, I get the error:
"Could not load file or assembly 'Interop.TsSDKActiveX, Version=1.0.0.0, Culture=neutral, PublicKeyToken=60b2ad56e2b9ec22' or one of its dependencies. The system cannot find the file specified."
How can I work around this? TsSDKActiveX does not exist in the GAC (but in my Program Riles (x86), which is why I assume it is not finding it. Also, I suspect the fact that sharepoint likes 64 bit DLLs is a problem.
I tried to isolate the code in a separate application and invoked it through a WCF service, but this has been giving some problem due to how this COM component works. I need to eliminate the service.
Any suggestions on how to proceed?
You cannot load 32-bit DLLs into 64-bit process, even through COM. You could possibly rely on COM to communicate across process boundaries but i dont think it applies in your case.
I think your initial approach with WCF is most natural one. Expose a thin WCF endpoint that wraps the interface for the COM wrapper object in managed code and then interact with it from SharePoint using standard WCF client API. Now, if you must have state in your interaction, create a business object within sharepoint process that maintains and only makes calls to WCF as needed. What was your reason to abandon the WCF?
I am planning to create a Licensing Module which can be commonly used for all Desktop Applications. So i thought of making it so simple without any or less coding in the existing applications which are going to be activated by this Licensing Module.
So is there any way where if the user passes the exe location, the system should capture the exe available in the particular location, and the system should get all the windows forms available inside that exe?
Am not sure whether it is possible or not but i need to know whether there is any way to do it. It would be helpful for me to develop this with less complications.
You can read the actual executable image data from its path and in case, its a managed (.NET) executable, you can use the metadata to do some analysis. In this case, you can browse through all types within the executable assembly (and perhaps other assemblies from the same directory) and find out the number of classes/types that are inherited from System.Windows.Forms.Form.
However, considering that these applications are probably in your control, the saner approach would be have an public API in these executable that will provide you the relevant information.
Guys i found a solution for this....i used the following method...
Assembly SampleAssembly = Assembly.LoadFrom("Assembly path here");
// Display all the types contained in the specified assembly.
foreach (Type oType in SampleAssembly.GetTypes())
{
Console.WriteLine(oType.Name);
}
this worked perfectly for me....
VinayC thanks for your support buddy...really appreciate it....:)
I have a DLL (written in C) that uses static thread local storage (__declspec(thread)), and I want to use this DLL from a Visual Basic graphic interface.
Unfortunately, when running the interface on Windows XP that DLL which use static thread local storage crashes when it try to acess its thread variables.
How can I solve this problem?
Thanks,
Regards
G.B.
PS
I would like to not modify the DLL.
This is a known limitation of static TLS. Although you aren't explicitly calling LoadLibrary(), the VB runtime does so on your behalf.
Note that this limitation has been lifted from Vista. The most comprehensive reference that I know of is on Ken Johnson's blog.
You may be able to get around the problem if you could get the DLL included in the imports table of the generated .exe, which would likely involve some PE hacking and I'm far from certain it's a viable strategy. Otherwise you'll need to change the DLL.
I'm using log4net logging in my software that consists of several applications.
I want to have one common library for this.
I created a library and put it in the conficuration file. In AssemblyInfo.cs placed attribute:
log4net.Config.XmlConfigurator(ConfigFile = #"c:\logging.xml", Watch = true)
It work for windows service, but in dosn't work for asp.net application.
It work in asp.net if delete attribute from common library and put in into global.asax. However, this leads to that section of the log4net configuration must be made in the windows service.
There is also a business process which causes our library through the
remouting. I want the logging was carried out there too.
Is there way around this?
In my opinion the library should not define where the configuration file is found. Maybe a better idea would be to have a helper method that allows you to configure log4net quickly; that method would take an optional parameter for the config file path and would try to load the configuration file from the specified path first and if that does not work fallback to some maybe the current folder, the application folder or even the web / app.config.
If you insist that it must be an absolute path then you need to give the IIS Application Pool user read access to this file. This way the configuration by attribute should work for services and ASP.Net applications. I do not understand what you mean by "remounting".