How to use class from other files in C with visual studio

Question

I am a newbie of C  and MS visual studio  and I want to use the C  class which defined in another file  but can t get it work   Here is the program cs and why can t I rename that file     using System   namespace TestCSharp2       class Program               static void Main string   args                        Class2 class2   new Class2                   here the IDE will complain that cant find namespace or balabala               class2 setValue 10               Console WriteLine class2 getValue   ToString                 Console ReadKey                        And here is the Class2 that I want to use in file Class2 cs   namespace TestCSharp2       class Class2               int i          public void setValue int i                        this i   i                    public int getValue                         return this i                      Should I  include or something  isn t use namespace enough       As some guys asked if they are in the same assembly same project  I presume they were  because here is the procedure how they are created    A new project using the template of Console C  Project  then the program cs was created by default  The Class2 cs was created with  File  -   New  -   File  -   C  class  and saved in the same folder where program cs lives    To be honest  I don t know if they are in same assembly   same project  but I guess they were

User · Answer

Yeah  I just made the same  noob  error and found this thread  I had in fact added the class to the solution and not to the project  So it looked like this     Just adding this in the hope to be of help to someone

User · Answer

namespace TestCSharp2         public   class Class2               int i          public void setValue int i                        this i   i                    public int getValue                     return this i                      Add the  Public  declaration before  class Class2

User · Answer

I was having the same problem here  Found out that the problem was with an Advanced Property of the file  There is there an option with the name  Compilation Action   may be not with the exact words  I am translating - my VS is in Portuguese     My Class1 cs file was there as  Content  and I just had to change it to  Compile  to make it work  and have the classes recognized by the others files in the same project

User · Answer

According to your example here it seems that they both reside in the same namespace  i conclude that they are both part of the same project   if you haven t created another project with the same namespace  and all class by default are defined as internal to the project they are defined in  if haven t declared otherwise  therefore i guess the problem is that your file is not included in your project  You can include it by right clicking the file in the solution explorer window    Include in project  if you cannot see the file inside the project files in the solution explorer then click the show the upper menu button of the solution explorer called show all files   just hove your mouse cursor over the button there and you ll see the names of the buttons   Just for basic knowledge  If the file resides in a different project  assembly then it has to be defined  otherwise it has to be define at least as internal or public  in case your class is inheriting from that class that it can be protected as well

User · Answer

It would be more beneficial for us if we could see the actual project structure  as the classes alone do not say that much   Assuming that both  cs files are in the same project  if they are in different projects inside the same solution  you d have to add a reference to the project containing Class2 cs   you can click on the Class2 occurrence in your code that is underlined in red and press CTRL      period  or click on the blue bar that should be there  The first option appearing will then add the appropriate using statement automatically  If there is no such menu  it may indicate that there is something wrong with the project structure or a reference missing   You could try making Class2 public  but it sounds like this can t be a problem here  since by default what you did is internal class Class2 and thus Class2 should be accessible if both are living in the same project assembly  If you are referencing a different assembly or project wherein Class2 is contained  you have to make it public in order to access it  as internal classes can t be accessed from outside their assembly   As for renaming  You can click Program cs in the Solution Explorer and press F2 to rename it  It will then open up a dialog window asking you if the class Program itself and all references thereof should be renamed as well  which is usually what you want  Or you could just rename the class Program in the declaration and again open up the menu with the small blue bar  or  again  CTRL    and do the same  but it won t automatically rename the actual file accordingly   Edit after your question edit  I have never used this option you used  but from quick checking I think that it s really not inside the same project then  Do the following when adding new classes to a project  In the Solution Explorer  right click the project you created and select  Add  -   Class  or  Add  -   New Item     and then select  Class   This will automatically make the new class part of the project and thus the assembly  the assembly is basically the  end product  after building the project   For me  there is also the shortcut Alt Shift C working to create a new class

User · Answer

According to your explanation you haven t included your Class2 cs in your project  You have just created the required Class file but haven t included that in the project      The Class2 cs was created with  File  -   New  -   File  -   C  class  and saved in the same folder where program cs lives    Do the following to overcome this   Simply Right click on your project then  -   Add  -    Existing Item       Select Class2 cs and press OK  Problem should be solved now   Furthermore  when adding new classes use this procedure   Right click on project -   Add  -  Select Required Item  ex - A class  Form etc

[c#] How to use class from other files in C# with visual studio?

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