Access static method from non static class possible in java and not in c#
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02-07-2021 - |
Question
Access static method from non static class with object. It is not possible in C#. Where it is done by JAVA. How it works?
example of java
/**
* Access static member of the class through object.
*/
import java.io.*;
class StaticMemberClass {
// Declare a static method.
public static void staticDisplay() {
System.out.println("This is static method.");
}
// Declare a non static method.
public void nonStaticDisplay() {
System.out.println("This is non static method.");
}
}
class StaticAccessByObject {
public static void main(String[] args) throws IOException {
// call a static member only by class name.
StaticMemberClass.staticDisplay();
// Create object of StaticMemberClass class.
StaticMemberClass obj = new StaticMemberClass();
// call a static member only by object.
obj.staticDisplay();
// accessing non static method through object.
obj.nonStaticDisplay();
}
}
Output of the program:
This is static method.
This is static method.
This is non static method.
How to do this in C#? thanks in advance..
Solution
C# forbids referencing a static method through instance.Method
, only Type.Method
is acceptable. To call a static method, you need to go through the type, not an instance.
In your case this means that StaticMemberClass.staticDisplay()
works, but obj.staticDisplay()
does not.
When a method is referenced in a member-access (§7.6.4) of the form
E.M
, ifM
is a static method,E
must denote a type containingM
, and ifM
is an instance method,E
must denote an instance of a type containingM
.
(C# Language Specification Version 4.0 - 10.6.2 Static and instance methods)
When a static member
M
is referenced in a member-access (§7.6.4) of the formE.M
,E
must denote a type containingM
. It is a compile-time error forE
to denote an instance.
(C# Language Specification Version 4.0 - 10.3.7 Static and instance members)
OTHER TIPS
You can't. You'll need to use the actual class, in your case
StaticMemberClass.staticDisplay();
You could create an instance member to wrap the call to the static member. Or make the static member an instance member.