namespace APIproject
{
public class ApiCallResponse //class1
class Program //class2
}
I have two classes in my code and both are in the same file name Program.cs.
I want to shift my ApiCallResponse class into another file like Program1.cs
And then I want to call the new file Program1.cs into Program.cs to access that class.
How can I do that?
If you want to have a class in a separate file, which is actually a common practice, you need to add a class file (*.cs) and write your code there.
After this, you need to reference a namespace that contains your class and then use your class as usual:
Program.cs:
using MySolution.Responses; //This is how you can connect different classes.
namespace MySolution
{
public class Program
{
public static void Main(string[] args)
{
var response = new ApiCallResponse();
}
}
}
../Responses/ApiCallResponse.cs:
namespace MySolution.Responses
{
public class ApiCallResponse
{
public ApiCallResponse()
{
}
}
}
Related
With File scoped types in C# 11, It will not be possible to implement a partial class for a file scoped class in a different file.
Will this be an exception with the file-scoped classes? because it will lose the purpose of partial class in this way.
Reference: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/file
With code generators you typically create a partial class in one file and ask the code generator to add functionality to this partial class in another file.
The code generator might want to create helper types in this other file to support the added functionality. The name given to this helper type could conflict with one of your types or types created by another code generator. This is where the file modifier is helpful.
This modifier is not meant to be applied to the partial class itself.
MyClass.cs (your code):
[GenerateHelpFunction] // Ask the code generator to add a method
public partial class MyClass
{
public void MyMethod()
{
var myText= new Text();
}
}
file class Text // Your class
{
}
MyClass.generated.cs (added by source generator):
public partial class MyClass
{
public void Help()
{
var sourceGeneratorsText = new Text();
...
}
}
file class Text // Helper type created by code generator
{
}
I want to use old code in a new project in c#.
This is the old code. It is saved in an arbitrary folder on my PC.
namespace OldCode{
class HellowWorld
{
public static void SayHello()
{
Console.writeline("Hello World")
}
}
}
I want to use this in a new project called new code.
using OldCode (?)
namespace NewCode
{
class SayHelloNew
{
HelloWorld.SayHello();
}
}
My question is, how do I link to my old project? Did I do it right with using OldCode? Or is there some other dependency file I need to set up?
Yeap, Let me describe for you,
First you should make public your class to access it in other sources by adding public modifier like this:
using System;
namespace Stackoverflow.OldCode
{
public class HelloWorld // <----------- make it public
{
public static void SayHello()
{
Console.WriteLine("Hello World!!!");
}
}
}
Then I suggest adding a prefix in every other namespaces to show they are related to each other, like
namespace Stackoverflow.OldCode;
namespace Stackoverflow.NewCode;
The NewCode project and the OldCode should be in one solution, if not now, right-click on the solution name and choose: Add>New Project... or Add>Existing Project...
Then you should add the NewCode project as a reference to the OldCode project:
step1:
step2:
Now you can access old project methods easily, like:
using Stackoverflow.OldCode; // <---- add the reference
namespace Stackoverflow.NewCode
{
class SayHelloNew
{
public static void SomeRandomName()
{
HelloWorld.SayHello(); // <----- call it
}
}
}
That is almost correct. The colon (:) needs to be removed from the namespace declaration and to access the HelloWorld class externally, it must be public.
OldCode\HelloWorld.cs
namespace OldCode
{
public class HelloWorld
{
public static void SayHello()
{
Console.writeline("Hello World")
}
}
}
NewCode\SayHelloNew.cs
using OldCode;
namespace NewCode
{
class SayHelloNew
{
HelloWorld.SayHello();
}
}
You will also need to ensure the compiler has access to OldCode on compilation, or, if using Visual Studio, add a Reference to the OldCode project in the NewCode project.
Add references in Visual Studio
To avoid repetitive definitions, I am trying to move internal function prototypes from the class One into a C# using My.Class.One directive (like import My.Class.One in Java).
In Java, this would change this code:
public class One {
public static void func1();
public static void func2();
public static int main(String[] args) { ... }
}
...into that code split into different files:
import My.Include;
public class One {
public static int Main(String[] args) { ... }
}
------------------------->8--------------------------------
package Include;
public class My {
public static void func1();
public static void func2();
...
}
After learning that Java 'packages' are named 'namespaces' in C# I came up with the following C# code which fails to compile (mcs One.cs My_include.cs -out:One.exe) with the error:
> "error CS0103: The name `func1' does not exist in the current context"
using System;
using My.Include;
public class One {
public static int Main(String[] args) { return funct1(); }
}
------------------------->8--------------------------------
using System;
namespace My {
namespace Include {
public class functions {
public static void func1();
public static void func2();
...
}
}
}
I tried many different naming conventions but I still get the same error. Can you tell me what I do wrong?
It looks like you want a partial class, so your main class file would look like:
// File: One.cs
using System;
public class One
{
static void Main()
{
// Your Main method here
}
}
And you would have a second file which looks like:
// File: One.Externs.cs
using System;
public partial class One
{
extern static void func1();
extern static void func2();
}
At compile-time, these two (or more) files are automatically combined to a single class by the compiler. This gives you the separation you appear to be looking for, but keeps the relevant definitions within the correct scopes.
The using directive is only partially synonymous to java's import directive - in C# using only provides a shortcut into a namespace whereas you're used to referring to a class or partial class with import.
At the moment I have created a new method in a new class, and I am trying to call this method from my main class:
Program.cs:
namespace ConsoleApplication2
{
class Program
{
static void Main(string[] args)
{
testing();
Console.ReadLine();
}
}
}
and the method is in "Class1.cs":
namespace ConsoleApplication2
{
class Class1
{
public static void testing()
{
System.Console.WriteLine("It works!");
}
}
}
You need to specify the name of the class that the method is on. So:
Class1.testing();
Sometimes you might of course need to also worry about the namespace that Class1 is in. In this case both Class1 and Main are in the same namespace. If they hadn't been though then you'd have had to call it like:
ConsoleApplication2.DifferentNamespace.Class1.testing();
or with a using declaration at the top of program.cs:
using ConsoleApplication2.DifferentNamespace
You have made testing a static method, so you can call the method in this fashion
static void Main(string[] args)
{
Class1.testing();
Console.ReadLine();
}
Is this what you want ?
You are missing the class declaration in order to use the static method:
Class1.testing();
Class 1 has to be a public class and then you can call Class1.testing()
This may be an ignorant question, but I'm unsure why I can not use namespace aliasing and extension methods together.
The following example works just fine:
Program.cs
using System;
using ExtensionMethodTest.Domain;
namespace ExtensionMethodTest
{
class Program
{
static void Main(string[] args)
{
var m = new Domain.MyClass();
var result = m.UpperCaseName();
}
}
}
MyClass.cs
using System;
namespace ExtensionMethodTest.Domain
{
public class MyClass
{
public string Name { get; set; }
}
}
MyClassExtensions.cs
using System;
namespace ExtensionMethodTest.Domain
{
public static class MyClassExtensions
{
public static string UpperCaseName (this MyClass myClass)
{
return myClass.Name.ToUpper();
}
}
}
However, when I alias domain as follows in Program.cs:
using Domain = ExtensionMethodTest.Domain;
The extension method no longer works..
This can be rather frustrating when I'm dealing with converting various domain objects to contract objects (let's say I have 4 domain assemblies and 4 contract assemblies) for use in a web service. Using aliasing would be very handy as I could alias as follows and continue to use the various extension methods (such as ToContract, etc.):
using BillingContracts = Namespace.Billing.Contracts;
using IssuingContracts = Namespace.Issuing.Contracts;
etc...
I look forward to the answer.. I'm sure it's straight forward, but I, for the life of me, can't figure out why it doesn't work.
Thanks!
Make sure to still add a non-aliased using statement:
Program.cs
using System;
using ExtensionMethodTest.Domain; //DON'T FORGET A NON-ALIASED USING
using MyDomain = ExtensionMethodTest.Domain;
namespace ExtensionMethodTest
{
class Program
{
static void Main(string[] args)
{
var m = new MyDomain.MyClass();
var result = m.UpperCaseName();
}
}
}
MyClass.cs
using System;
namespace ExtensionMethodTest.Domain
{
public class MyClass
{
public string Name { get; set; }
}
}
MyClassExtensions.cs
using System;
namespace ExtensionMethodTest.Domain
{
public static class MyClassExtensions
{
public static string UpperCaseName (this MyClass myClass)
{
return myClass.Name.ToUpper();
}
}
}
I also love to use namespace aliasing but its not working in case of Extension methods. So one thing that i did is, I changed the namespace of extension class to same namespace that my main project has (although my extension class resides in sub folder of main project).
Suppose I have a project myFirstProj which surely has namespace myFirstProj for root classes. My extension class is present in myFirstProj/Common/myExtensionClass with contains namespace myFirstProj.Common { //myExtensionClass }.
So now what I did is, I changed the namespace of myExtensionClass from namespace myFirstProj.Common{ //myExtensionClass } to namespace myFirstProj{ //myExtensionClass } .
Now i can use my extension methods in my whole project myFirstProj event without specifying using statement for my extension class.
I know this isn't a standard way to that but I haven't found any other workaround for it expect this one because for my Project there is a requirement to go with namespace aliasing for project namespaces.