Develop Reference

How to use a class of one project in another project under the same solution?

I have two projects of Web API and Windows Forms App under one solution.
The names are:
Solution - CliendAddress
Web API - ClientAddress
WFA - ClientAddressWFA
In the ClientAddress project there is a class called ServiceResponse. How can I use this ServiceResponse class in my project ClientAddressWFA?
From my ClientAddressWFA, I've already added the reference to ClientAddress 👇
However, when I am trying to add using ClientAddress.Models; (<---- This is where the ServiceResponse class is) in my ClientAddress.WFA project, I'm getting an error👇
Recording: https://screenrec.com/share/XTp0dwbI42

If you need just this one source file then you can just add it to the other project "as link". Quick and dirty, but who cares. However, if you need more classes, then make a shared library project that would then be referenced by both projects. That's what shared libraries are for.
So, in project ClientAddressWFA try to add this one .cs file but instead of clicking "Add" click on small triangle next to "Add", and select "Add As Link".

Sometimes just restarting the visual studio and compiling again will work (Given that class you are referencing from another project is public and you have added project reference)

Adding UserControl from another project in xaml [duplicate]

Iv'e downloaded a C# interval tree collection class class from here http://intervaltree.codeplex.com/SourceControl/list/changesets -> Right hand side -> Download.
However I can't open the whole project on my Microsoft Visual C# 2010 Express (that also runs C# XNA) because
Solution folders are not supported in this version of the application
Also I just want the class to use separately in my own seprate project.
I tried to copy the three important seeming files Interval.cs, IntervalNode.cs and IntervalTree.cs into my project but this generated the compile error
There are no importers which handle this file type
I've also tried to copy and paste the contents of the three files into my project, encapsulating them into there own namespace as well as there was a lot of code. I had to rearange some of the usings a little but have run into the problem that possibly it wants PowerCollections .dll and .pcb files as using Wintellect.PowerCollections; causes
The type or namespace name 'Wintellect' could not be found (are you missing a using directive or an assembly reference?)
I'm not sure how to continue or if I'm doing the right thing at all in how to get this class to work.

Add the library to your solution
Copy the IntervalTreeLib directory into your solution directory. Then, right-click your solution, and add existing project. Point it at IntervalTreeLib.csproj in IntervalTreeLib, and click Open. That should add the IntervalTreeLib project to your solution.
Add a reference to the library in your project
Then, in your project, add a reference to the IntervalTreeLib proejct:
- Right click the References folder, and Add Reference. Click the Projects tab, and select IntervalTreeLib.
Use the classes in your code
To use classes from the library in your source then, you need to either add:
using IntervalTreeLib;
void Foo() {
IntervalTree<int, int> tree = new ...
}
Or, refer to them by their full name:
IntervalTreeLib.IntervalTree<int, int> tree = new ...

Open the IntervalTreeLib.csproj file if you want to be able to open the project in it's entirety (or in your current solution add an existing project (you can right-click on the solution) and select the IntervalTreeLib.csproj). If you are trying to grab just the code file in your project, ensure you also grab the PowerCollections.dll file (I see it is in the same folder as the code files) or your code will not compile (as you have discovered). You'll need to add a reference to it and include the needed using statement at the top of the code files making use of this library (or use fully qualified name with the namespace).
using IntervalTreeLib;
or
var myObj = new IntervalTreeLib.[WhateverClass](...);
Also, make sure you read the license.txt file. You may need to include it if you are using the code. Give credit where it is due.
UPDATE:
If the test project is causing you problems, just open the library project. Ideally you could just open that and compile it, adding the output DLL files that are generated directly into your solution. This is ideal unless you are planning on changing the library source code itself.

Add the library to the references of the project you want to use it.

Since discussing that you are able to build Intervallib.dll, we will discuss about how you should the dll in your project.
Now in your proj, right click on the references part and add the dll intervallib.dll to your references. In your game.cs file, have the reference to the namespace as -- using IntervalTreeLib;
then you should actually copy the dll powercollections.dll to the bin directory of proj directory also.
you should copy this dll because there is an indirect link to the dll as it is used in IntervalTreeLib.dll
following these steps, I was able to execute this project.

Build same Project as Console and DLL

I've got an C# Project in Visual Studio, which has Console Application as Output Type.
But I also need a Class Library of this project for another solution.
Right now I have to switch the output type every time, but I wonder if it's possible to generate exe and dll at the same build-event?
Is there a post-build-event for this?

To my knowledge there is no possibility to change the output type after compilation. That being said, if would be possible to have two projects like Console and Library in your solution, which would use the same source code files but have different output types. That way you would have different outputs without any duplication of code.

it is generally possible to reference a .net exe assembly as it would be a class-library.
So you can just stick in creating an exe file and reference the exe (sounds strange, but works) in your other project.
This is the dialog for browsing for references. As you see you can select exe files.
But as commented it really depends on what your usecase is.
I don't recommend to ship an exe with an entry point to your customer hoping that the customer does not discover the exe. But what you could do about that is to conditionaly compile your entry point.
For example
class Program {
// This is the entry point of the EXE
public static void Main() {
#if DEBUG
// Start Debug Application
...
#else
// Shipped to client - Entry point disabled
return;
#endif
}
}
If there is a relevant reason to have a shipped exe and a shipped class library, I would refactor your solution like this:
(A) complete application (.sln)
(B) console-application (.csproj) which has a reference to (C)
(C) class library project (.csproj)
With that it is perfectly clear to others that there is an application that uses the library and the library itself.

Console Application is the type of your project. You can not change it.
What you can -and must- do is, carry your logic into a Class Library project and use your class library from any type of project you want.

You should compile your project to become a dll and then use this dll in a console application.
A possibility to achieve what you want is to manually run the msbuild on your post-build event of your project.
See: How do i build a solution programatically in C#?
or Building C# Solution in Release mode using MsBuild.exe

The usual solution for this is using a Solution with two projects:
a Class Library with all the code (which builds into a DLL)
an Console Application referencing the library whose Main just calls some function(s).
For more information, check the MSDN page on Solutions.
Codor suggested manually adding the files to the Console project, but one downside is that build settings are not shared between both versions, so you might get some inconsistency there.

I'm not really sure why people think it's not possible but it actually is.
The easiest way would be renaming the exe to dll Sounds stupid, I know. But it works in many cases. Also, as "Peter I" said a .NET exe can be imported as assembly in other projects. So you might not actually need a dll anyways.
Another way would be using C# command line as stated here: /out (C# Compiler Options)
You can use command command line options in Pre/Post build events Pre-build Event/Post-build Event Command Line Dialog Box

I have a similar requirement and couldn't find any definite answer in this post or anywhere. I currently have a class library and would like to create a console application project without copying any code. Ideally speaking there should be two projects, one for creating a console application and another for creating a class library. And this is what the visual studio also suggests. When I tried to run the class library, I got the below message.
It clearly asks us to add an executable project to the solution and add the reference to the library project.
Below are the steps to do this.
Right click solution -> Add new project -> Console App -> choose name -> ok.
Right click on the console project -> add reference -> In reference manager, click on the projects tab and select the other project(In my case this is the class library project, In case it is not listed just click on browse and select the .csproj file) -> ok.
Now to use the classes in the other project, simple do using LibraryProjectNameSpace
There we are. Bingo!!!!
Also as mentioned in the other answers it is not possible to have the same project generate both .exe and .dll. But you can have the same solution generate these two guys by having two projects. In this way there is no need to switch the output of the project every time.
FYI, I use visual studio 2017

Changing source code in a class library seems to have no effect on application

I was given a project in which I am supposed to debug a problem in a Windows Forms application. I found where the problem is located but it is within a Class Library which is included as a component of my Windows Forms application solution.
How can I add/modify code in the Class Library project and actually run it live so that I can debug it? If I make any changes to the Class Library as is, the application ignores the changes and resorts to the original source code.
The only things contained in the Class Library's folder are plain source code files, some settings files, and a .vbproj. I just want to make changes to the Class Library and actually be able to debug them. If anyone could please explain what I have to do, it would be greatly appreciated!

Your application is not loading the assembly produced by compiling the class library. It is loading another copy from somewhere.
One quick way to find out where is to start the application from Visual Studio, break into the debugger and then bring up the Modules windows (Debug>Windows>Modules). Look for the class library in the Name column and check the Path.
If it is under C:\Windows\Microsoft.NET\assembly... then there is an older version being loading from the GAC. If it's another location, you will need to ensure the class library project output is going to that location.
Does the startup project have a project reference to the class library in the solution? You could always remove and re-add the reference to the class library in the startup application project and ensure you add it as a project reference.
Be careful though, there may be a good reason why this wasn't the case originally.
EDIT
A full explanation of how assemblies are located is way beyond the scope of an SO post - you'll need to study How the Runtime Locates Assemblies.
With no changes made to typical solution defaults, a library is most likely to be loaded from the same folder where the start-up executable is located. Setting a project reference to a library causes it to be compiled and copied to that project's bin folder - so make sure the startup project has a project reference to your class library project. (Right-click startup project and check Add References... dialog. The reference should come from the Solution section).
You'll need to examine the project property pages to see if something special has been configured.
99.99% of the time, building the WHOLE solution and hitting run should work. If it doesn't work, something is messed up in the solution and/or there is some kind of custom deployment set up.
There are simply so many ways to deviate from the default deployment that I just can't give specific guidance here; you best bet is to get someone knowledgeable who can take a look in person, or to whom you can send the source for inspection.

I just went to Project Properties ....Project Dependencies and checked(ticked ) the class /assembly(.dll) name... It worked for me. Now i dont need to run the class project for the changes to reflect in the Startup Project ..

How to create a dll file

Using Visual Studio 2005
I have list of class files, when i try to run the class files, it showing error as
"a project with output type of class library cannot be started directly"
How to run the class file? How to create a dll file.
Am new to visual studio 2005
Need Help?

A Class Library is just that, a library of code, you need to create an application that references the library to try it out.
In the same solution, just add a new project as a Winforms Application and then in the winforms application project add a reference to the class library project.
You should then be able to call the methods in the library from the application code.

To create a DLL File, click on New project, then select Class Library.
Enter your code into the class file that was automatically created for you and then click Build Solution from the Debug menu.
Now, look in your directory: ../debug/release/YOURDLL.dll
There it is! :)
P.S.
DLL files cannot be run just like normal applciation (exe) files. You'll need to create a separate project (probably a win forms app) and then add your dll file to that project as a "Reference", you can do this by going to the Solution explorer, right clicking your project Name and selecting Add Reference then browsing to whereever you saved your dll file.
Then, to be able to use this dll file, in your projects code, you call the methods inside the dll file. For example:
If, in your DLL file you have a method like this:
public string somerandommethod()
{
string x = "something";
return x;
}
Then, in your Form1.cs file of your separate project, you would call the code from your dll file like this:
button1_Click(object sender, EventArgs e)
{
MyDllFile dll = new MyDllFile();
MessageBox.Show(dll.somerandommethod());
}
I hope this has helped you

You cannot run projects of type class library. You need to define a startup project that is either a console application, windows application or a web application which would use the class library.

If you are creating a library, look at using something like NUnit to test it. It will load the dll and execute whatever tests you define on it.

You can not run a class file, either you can go to project properties ->Application - > Output type. Here you can specify the application type as console application so your code will run on command prompt.
Also make sure that the project you are trying to run is set as startup project (you can do it by right click on project and select "Set as Startup project".
To create a DLL you need to select New Project -> Class library.