Let's say I have a contract
public interface IGreeting
{
string SayHelloWorld();
}
And a class in another dll
[Export(typeof(IGreeting))]
public class Greeting : IGreeting
{
public string SayHelloWorld()
{
return "GREETING V1";
}
}
I use directorycatalog to get this DLL. I works fine. When I update my source code like this:
[Export(typeof(IGreeting))]
public class Greeting : IGreeting
{
public string SayHelloWorld()
{
return "GREETING V2";
}
}
and put this new DLL "Next" to the old Greeting DLL Mef doesnt import multiple different Greeting classes but picks 1 out of 2 DLL and exports 2 times from the same class.
So final executing directory looks like this:
MyApp.exe
Greeting_V1.dll
Greeting_V2.dll
I want the application to import 2 Greeting classes with ImportMany. It gives me 2 instances from Greeting_V1.dll. If I delete Greeting_V2.dll it gives me only 1 instance of Greeting_V1.dll.
Well, to me, it looks like you are importing many instances of IGreeting, so in that sense, MEF is doing exactly what it is supposed to do. If you want to replace the instance of Greeting from the V1 assembly with what is in V2, remove the V1 assembly, that way MEF can only load what is available.
It not a MEF problem. The problem is in the loading model of .NET. (or better the way you're objects are loaded by .net)
When MEF loads it returns the correct objects. But when looking for class Greeting when V2 is loaded there is already a Greeting class for V1 dll loaded with the correct class Greeting name for V2 is referring to. And the loader the dll actually referenced by V2 is not loaded.
Related
I know this was aksed and answered a a couple of times e.g.
Solution-wide #define, Is There anyway to #define Constant on a Solution Basis? and How to define a constant globally in C# (like DEBUG).
But in my case I can not use any of the suggested methods:
I'm writing on different "modules" (or plugins if you want so) for UnityProjects (kind of a package providing a certain functionality). The idea is that a developer can load a certain "module" to use in his project by importing a UnityPackage with all scripts and resources in it.
But some of these modules themselves depend on other modules. So what I tried so far was having a class Constants in each module with seperated namespaces and preprocessor definitions.
Module A
#if !MODULE_A
#define MODULE_A // BUT I WOULD NEED THIS GLOBAL NOT ONLY HERE
#endif
namespace Module_A
{
public static class Constants
{
// some constants for this namespace here
}
}
Module B
#if !MODULE_B
#define MODULE_B // BUT I WOULD NEED THIS GLOBAL NOT ONLY HERE
#endif
#if !MODULE_A // WILL BE NOT DEFINED OFCOURSE SINCE #define IS NOT GLOBAL
#error Module A missing!
#else
namespace Module_B
{
public static class Constants
{
// some constants for this namespace here
}
// and other code that might require Module A
}
#endif
But ofcourse this cannot work like this since #defines are not global but only in the current file.
Problem
For this whole idea of modules and a simple "load your modules" I can not ask the user to first make changes to the project or solution settings how e.g. suggested by this answer but instead have to use only the (c#) resources that come imported with the UnityPackage (at least with my current know-how).
Is there any way to somehow set/define those constants for the entire Unity-Project by only importing the module's UnityPackage?
Edit:
I could find a solution for 1 definition in Unity using Assets/msc.rsp. But this still wouldn't work for multiple modules since they would have to write into the same file.
After a lot of searches I've finally been able to put together a surprisingly simple solution I'ld like to share with you:
InitializeOnLoad
Unity has an attribute [InitializeOnLoad]. It tells Unity to initialize according class as soon as
Unity is launched
After any re-compiling of scripts => also after importing a new unitypackage with scripts
static Constructor
In their Running Editor Code On Launch example, they show, how to combine this with a static constructor.
From static-constructors:
A static constructor is called automatically to initialize the class before the first instance is created or any static members are referenced.
While usually you still would have to create an instance of the class, the static constructor is "instanciated/executed" instantly when the class is initliazed, which we force using the [InitializeOnLoad] attribute.
Scripting Define Symbols
Further Unity actually has project wide defines in the PlayerSettings.
And the good part is: We also have access to them via scripting API:
PlayerSettings.GetScriptingDefineSymbolsForGroup
PlayerSettings.SetScriptingDefineSymbolsForGroup.
So what I did now is the following
Module A
This module has no dependencies but just defines a "global define" in the PlayerSettings. I placed this script somewhere e.g. in Assets/ModuleA/Editor (important is the last folder's name).
using System.Linq;
using UnityEditor;
namespace ModuleA
{
// Will be initialized on load or recompiling
[InitializeOnLoad]
public static class Startup
{
// static constructor is called as soon as class is initialized
static Startup()
{
#region Add Compiler Define
// Get the current defines
// returns a string like "DEFINE_1;DEFINE_2;DEFINE_3"
var defines = PlayerSettings.GetScriptingDefineSymbolsForGroup(EditorUserBuildSettings.selectedBuildTargetGroup);
// split into list just to check if my define is already there
var define = defines.Split(';').ToList();
if (!define.Contains("MODULE_A")
{
// if not there already add my define
defines += ";MODULE_A";
}
// and write back the new defines
PlayerSettings.SetScriptingDefineSymbolsForGroup(EditorUserBuildSettings.selectedBuildTargetGroup, defines);
#endregion
}
}
}
Module B
This module depends on Module A. So itself defines a "global define" (so later Modules can check their dependecies on Module B) but additionally it checks first, if Module A is imported. If Module A is missing, it prints an error to the Debug Console.
(You could as well throw a compiler error using #error SOME TEXT, but for some reason this is not capable of printing out the URL correctly so I decided for the Debug.LogError)
I placed this script somewhere e.g. in Assets/ModuleB/Editor
#if MODULE_A
using System.Linq;
#endif
using UnityEditor;
#if !MODULE_A
using UnityEngine;
#endif
namespace ModuleB
{
// Will be initialized on load or recompiling
[InitializeOnLoad]
public static class Startup
{
// static constructor is called as soon as class is initialized
static Startup()
{
#if !MODULE_A
Debug.LogErrorFormat("! Missing Module Dependency !" +
"\nThe module {0} depends on the module {1}." +
"\n\nDownload it from {2} \n",
"MODULE_B",
"MODULE_A",
"https://Some.page.where./to.find.it/MyModules/ModuleA.unitypackage"
);
#else
// Add Compiler Define
var defines = PlayerSettings.GetScriptingDefineSymbolsForGroup(EditorUserBuildSettings.selectedBuildTargetGroup);
var define = defines.Split(';').ToList();
if (!define.Contains("MODULE_B"))
{
defines += ";MODULE_B";
}
PlayerSettings.SetScriptingDefineSymbolsForGroup(EditorUserBuildSettings.selectedBuildTargetGroup, defines);
#endif
}
}
}
So later in other scripts of Module B I have two options (both do basically the same)
I can either check everywhere #if MODULE_A to check exactly the module this script relies on
or I can instead check #if MODULE_B to rather check with one line if all dependecies are fulfilled since otherwise I don't define MODULE_B.
On this way I can completely check all dependencies between certain modules which is awesome. The only two flaws I saw until now are:
We have to know how the define (e.g. MODULE_A) looks like for every module and if it is changed in the future it has to be changed in all depending modules as well
The "global define" isn't getting removed in case the module is deleted from the project
But well - which solution is perfect?
In general, the way I would solve this problem in C# is by defining a common set of interfaces that all your modules would contain. I think you can do this with Unity by placing the files from each module in the same location, thus allowing later installations to overwrite those same files (with, obviously, the same content). You would then put editor controls that expose properties to hold instances of those interfaces and then wire them up in the UI. You would test those properties for a value of null to determine which ones are missing.
Common.cs:
public interface IModuleA {}
public interface IModuleB {}
ModuleA.cs
public class ModuleA : IModuleA {}
ModuleB.cs
public class ModuleB : IModuleB
{
public IModuleA ModuleAInstance {get; set;}
private bool IsModuleAPresent()
{
return !ModuleAInstance == null;
}
}
The ideal way to solve it would be with a package manager and proper dependency injection, but doing that with Unity is not straightforward.
OK, so inside a class library, is it a good idea NOT to use MEF?
Here is an example:
ISomeInterface
5 Implementations of ISomeInterface
Once class that imports all ISomeInterface and uses them.
Again, this is all inside a single dll. Since it is in a DLL, there is no bootstrapping of MEF to create the catalog, and it seems a bit much to build a catalog just to use it once.
Am just learning MEF and how to use it.
Greg
After reading up a bit more on this, it looks like there is no reason that MEF can't be used inside a DLL for it's own parts creation. When I asked this question, I was thinking that the Importing would be mainly inside a Main() or App() type of function to compose the entire app. But if composing needs to be done on a major part that gets exported to the app, it can still use MEF to compose itself in the constructor, like this:
//An aggregate catalog that combines multiple catalogs
var catalog = new AggregateCatalog();
//Adds all the parts found in the same assembly as the Program class
catalog.Catalogs.Add(new AssemblyCatalog(typeof(Program).Assembly));
//Create the CompositionContainer with the parts in the catalog
_container = new CompositionContainer(catalog);
//Fill the imports of this object
try
{
this._container.ComposeParts(this);
}
catch (CompositionException compositionException)
{
}
I created an ASP.NET webapplication with dynamic data. I'm fairly new to this so I'm struggling with alot of things but now I'm completely stuck.
Thing is, I want to hide, lets say, the name column of a table in my database (model based on entity framework). Therefor I added a new folder named "AppCode" (because I cannot add the default app_code folder in a web app) and added a file named "User.cs" The contents of this file look like this:
[MetadataType(typeof(UserMetaData))]
public partial class User{
}
public class UserMetaData
{
[ScaffoldColumn(false)]
public object Name;
}
Now, after running the application I did not expect to see the name column in the crud pages, but it is still there. What am I missing here?
Thanks alot.
Finally figured it out myself. What went wrong was the fact that my model was placed in a referenced class library and not in the dynamic data project itself. It seems to be very important that the namespace of the partial class is the same as that of the model. Otherwise it would not work. So, in my case I had to place the partial class in my "domain" project which contains the model. Hope this helps someone.
Is there some global state somewhere that I can access the currently-running test name?
I have tests which output files into a directory and read them back in. I'd like each test to create a directory to play in and then clean up after itself, and I don't want to push that name in (I'd have to make it unique, and then make sure each test keeps it unique; ew). I could use a GUID, but I'd like helper methods to be able to assume "this is the place where test files should be stored" without having to push that GUID around to them. Again, this augers for a global state somewhere.
Basically, I want a call like TestRunner.Current.CurrentTest.Name. Does such a thing exist?
(Assuming c#)
NUnit.Framework.TestContext.CurrentContext.Test.Name
or
NUnit.Framework.TestContext.CurrentContext.Test.FullName
or if you are really lazy and aren't driving your tests with TestCaseSource (thanks #aolszowka):
this.GetType().ToString()
I haven't upgraded to 2.5.7 yet myself, but it includes a TestContext class that seems to provide just what you're looking for: http://www.nunit.org/index.php?p=releaseNotes&r=2.5.7
Assuming one method per Test, in your NUnit code, you can use reflection to get the method name from the stacktrace.
If you write a helper method in your NUnit code called by other methods to do this file logging, you can use this syntax to check for the previous method:
string MethodName = new StackFrame(1).GetMethod().Name;
See the answers to question 44153, "Can you use reflection to find the name of the currently executing method?" for more details.
If we are using TestCaseSource tag then above solutions might not give correct answer
Try using TestContext.CurrentContext.Test.MethodName
Follow the below example
namespace NunitTests
{
public class Class1
{
static List<TestData> Data = new List<TestData>()
{
new TestData()
{
...
}
};
[Test]
[TestCaseSource(nameof(TenMBInstance))]
public void TestCase(TestData value)
{
TestContext.CurrentContext.Test.Name; //TestCase(NunitTests..TestData)
TestContext.CurrentContext.Test.MethodName; //TestCase
}
}
}
I have an ASP.NET 3.5 web application project in which I'm trying to implement a searchable gridview. I originally started the project as a web site and converted it to a web application. After conversion, my class ended up in the folder Old_App_Code and is called SearchGridView.vb.
Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Text
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Drawing.Design
<Assembly: TagPrefix("MyApp.WebControls", "SearchGridView")>
Namespace MyApp.WebControls
#Region "TemplateColumn"
Public Class NumberColumn
Implements ITemplate
Public Sub InstantiateIn(ByVal container As System.Web.UI.Control) Implements System.Web.UI.ITemplate.InstantiateIn
End Sub
End Class
#End Region
<ToolboxData("<{0}:SearchGridView runat=server></{0}:SearchGridView>")> _
<ParseChildren(True, "SearchFilters")> _
Public Class SearchGridView
Inherits GridView
The class file continues, but this is the first part of it.
Unfortunately, I receive the error message
Warning 1 Namespace or type specified in the project-level Imports 'MyApp.WebControls' doesn't contain any public member or cannot be found. Make sure the namespace or the type is defined and contains at least one public member. Make sure the imported element name doesn't use any aliases. DielWebProj
In web.config, I included a namespace tag for MyApp.WebControls and I included an imports tag in the .aspx page as well.
Can anyone shed light as to why this error is being raised and how I would remedy it?
Thanks,
Sid
I have a broadly similar problem to you. I have a website project using a custom control, inheriting from GriView, in the app_code folder. I was recieving the very same error, but noted that it happened only after I would add a second class or module to app_code, and would disappear if I removed it.
So the workaround I have at the moment is to just leave my custom control as the sole occupant of app_code.
One option might be to make the control part of its own project and add it as a reference to the we site/app?
I'll update this if I can find a decent solution.
EDIT:
Well, in my case it was because the control I was using was written in C#, whereas the rest of the project, and classes I added to app_code, were in VB.
The app_code folder is compiled to a single assembly, so classes of different languages cannot share it, unless you create seperate sub-folders and do some config file jiggerypokery. More details here