What does this dotted file icon mean? It's a .cs file but it is not behaving right in my project and I've noticed this separate icon in Solution Explorer:
I've checked the MSDN Documentation in three places
Another page at MSDN
Yet another page at MSDN
I've also checked the Visual Studio Documentation itself, which is rather obscurely organized.
I've even checked this website:
Lastly, I found this topic with a similar question but both the question page and the references inside do not have this icon. Thanks for your help.
This means that the file isn't included in the project.
You're only seeing it because you turned on Show All Files.
You should right-click the file and click Include in Project.
You have "Show all files" checked.
The dotted lines indicate files that have not been added to your project.
Right click on the file and click "Include in project" to include the file in your project.
That "dotted" icon mean that that file is not a part of your project or it is hidden and it is not included in your project.
That "dotted" icon is pretty similar to the icon in Solution Explorer called "Show all files". When you click on it you can see all the files and maybe you click on it or you have some issue and your file is not included in the project.
To include it you can right click one of those files go to Include In Project and that will add it to the project, which declares it in the manifest of your project. You can do it like this:
It is not included in your project and/or hidden.
I did a huge plunder and accidentally lost my *.cs (Design file).. I just got the *.designer file left.
Can I go the other way around and create somehow a Design-File (*.cs) only with the .designer file or do I have to start over?
Please have a look in Recycle Bin and click restore. So you will get your file back in visual studio solution explorer with excluded status. Right click and include in project.
To avoid this type situations, use version controls in your project like:
TFS - Team Foundation Server
GIT
Visual Source Safe
SVN
I have a solution that contains few projects.
The problem is that when I want to open just one of the projects by clicking on the specific .csproj file, it opens all the solution.
How can I open just one project?
Thanks.
You can create a new solution, and add this project to the solution.
Then this project will have a solution of it's own.
It's a hack but rename the .sln file to some other extension temporarily, then double click the csproj. Visual Studio seems to have intellismarts about detecting solutions.
The only way I have been able to do this is to remove the project from the main solution and save it and close it.
You should now be able to open the solution and the project file independently.
Note: opening the csproj file will create a new solution for you.
Why do I want to open a single project from a solution?
I have a solution with 66 subprojects, so it is helpful if you can only edit a single project. I have already tried many possibilities, as described above.
Today I mostly do it with the command "Scope to this" in the project explorer. So I have the focus only on one project. So I hope this tip was helpful for you :-)
Depending on your needs. I just want to open the project so I copied the projectfolder to a temp folder and then I just open the project.
But I don't want it in version control and all edits will be lost unless overwrite to the original folder.
You can't. The basic unit of Visual Studio is a solution.
I downloaded a C# project and I wish to debug the project to see how an algorithm implementation works.
The project has come in a Folder, inside this folder there are -
.sln file and
a folder which has source files and a .csproj file.
I installed Visual Studio and opened the .sln file present in the main folder. I built the project successfully, but when I try to debug the project I get this message:
A project with an Output type of Class Library cannot be started directly In order to debug this project, add an executable project to this solution which references the library project. Set the executable project as the startup project.
The strange part is that I don't see a main function anywhere.
What should I do to get round this hiccup?
The project you have downloaded compiles into a dll assembly and provide a set of classes with implemented functionality.
You should add to your solution a new project with Output Type of either Console Application or Windows Application (VS Add Project wizard will offer you different templates of Projects).
In the newly added project, you can implement logic to test your Class Library.
Output type of the project you can find and change by the following steps:
Right click on project in Solution Explorer -> Properties.
In opened tab with properties select Application and there will be ComboBox marked with Output Type label.
Just right click on the Project Solution
A window pops up.
Expand the common Properties.
Select Start Up Project
In there on right hand side Select radio button with Single Startup Project
Select your Project in there and apply.
That's it. Now save and build your project. Run the project to see the output.
This was the solution that worked for me since I couldn't find 'Common Properties' option.
Select your topmost level project in Solution Explorer.
Go to Project, and in contextual menu Set as StartUp Project.
See also: A project with an Output type of Class Library cannot be started directly
Just needs to go:
Solution Explorer-->Go to Properties --->change(Single Startup project) from.dll to .web
Then try to debug it.
Surely your problem will be solved.
The strange part is that I don't see a main function anywhere.
That is exactly your problem. The project merely creates a DLL. It has no executable to run.
You will need to add a second project, which is an executable which references the other project, and calls something in it.
1) Right Click on **Solution Explorer**
2) Go to the **Properties**
3) Expand **Common Properties**
4) Select **Start Up Project**
5) click the radio button (**Single Start_up Project**)
6) select your Project name
7) Then Debug Your project
Right Click on "Solution Explorer" -> "Properties"
Expand "Common Properties"
Select "Start Up Project"
click the radio button "Single Start_up Project"
select your Project name from the drop down list.
If still not working after the above steps, then try this.
Expand solutions explorer.
Right click on project name -> "Properties"
Go to "Application" tab
Select "Output type"
From the drop down list select the appropriate type according to your application.
"Windows application" or
"Console application"
Then save (ctrl + S)
Try debugging (F5)
You'll need some kind of app (Console Apps are my favorite for debugging, but a WinForm will do) which uses your Class Library. Just add a new project (in the same solution) of a Console Application or Windows Forms Application, and add a reference to your current project. Once you've done that, make any calls you need, set your break points, and go to town.
I had a similar issue when trying to use the Experimental Instance of Visual Studio 2013. This was for a vsix project (Creating Snippets).
Solution was:
Right Click Project in Solution Explorer > Properties > Debug
Setting the Start Action to "Start external program" and using the following path:
C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\devenv.exe
This option was set to "Start project" which won't work for the application output type Class Library, which caused that same error.
Note: Yours may differ depending on how you installed VS.
Error solutions is that you have already open your project but by mistake you have selected another class library .. that's reason this error is showing ... so what u need to do you u just select u r project then right click on u r project
after right click u can see the list box and select the "Set as start up project " option .
Accepted answer works if your solution has a project that compiles to an exe. If your solution does not have any projects that compile to an exe, then you have to use 'Start external program'.
VS2019 instructions:
right click -> properties on the main solution
debug, start external program, and add command line arguments
VS2022 instructions:
right click -> properties on the main solution
scroll down to Debug
Debug > General > Open debug launch profiles UI
left click the 'new' icon in the top left, select 'executable'
fill it out as per VS2019 (pick the exe and add command line arguments)
when clicking the start button, first select the profile you made
Suppose you have multiple project in the solution. Select the project that you want to view in browser and select 'Set as StartUp Project'. In your multiple project soln which was the main, the visual studio was unable to identify. this was the main problem.
You can right click the Class Library project and from the drop-down choose Initialize Interactive C# which will load your project context and you can work it in the interactive session.
In my case, the cause was that one of my projects in the solution wasn't loaded. The reason it couldn't load properly was that the file path length of one of the files was too long. Upon deleting this long file, I could reload the project, and build the solution.
If the question involves an Azure project, make sure you have the "Azure development" tool set installed, or when you go to run a solution you may get this same error.
Tools > Get Tools and Features... > Tick the box next to Azure development > Click install
None of the answers provided above helped me resolve this error, this is what resolved the issue for me.
Right click on the solution and select "Properties", which is in my case "Sintctech.Data".
Select the section called "Application".
Check what you have selected as your output type. If it is "Windows Application", change it to "Console Appication".
Rebuild and the problem should be fixed.
This may be a ridiculous question for you C# pros but here I go. I'm a Flash developer getting started in Silverlight and I'm trying to figure out how to create a "codebase" (a reusable set of classes) for animation. I'd like to store it in a single location and reuse it across a bunch of different projects. Normally in Flash I would add a "project path" reference and then start using the code. My question is, how do I add a folder to visual studio so that I can "use" those classes in my project. I tried "Add > Existing Item" but that copied the files into my project directory.
The easiest way would to create a new ClassLibrary project and build it. This will output a .dll file in a folder you can specify in the project settings menus, which you reference from every project that needs it.
Also, you can copy this .dll into the /bin/ folder of your project - this will do the same thing for this specific project, but when you start the next one you can change some details in the codebase library without breaking the first project.
The solution described by Tomas (adding a reference to a dll binary) is the correct solution to this problem; better than referencing the source code and compiling it into each project.
But just for extra information, if you ever do need to add a source code file to your Visual Studio project without having it make a copy of the file you can use the following steps:
Right click on your project in Solution Explorer and select Add -> Existing Item.
Navigate to the location of the source code file and select it.
On the "Add" button in the dialog window there is a drop down arrow. Click this and select "Add as Link".
This will allow you to use this source code file in your project without having VS make a copy of the file.
In Solution Explorer, right-click on the project node and click Add Reference.
In the Add Reference dialog box, select the tab indicating the type of component you want to reference. (for instance for a class library a dll)
Select the components you want to reference, then click OK.