Const Object Reference in C# function

[Shreyas Ranade]

I want to pass an Object Reference to a C# function, but also I want to make
sure that the calling function should not change it's value.
The C++ Code Like

MyClass cls;
Fun1(cls)

void Fun1(const MyClass & cls)
{
int a = cls.m_No;
}


I want to write same code in C#. How should I write because
you can not send Cont Object Reference to a function in C#.

 

[Greg Ewing [MVP]]

Shreyas, there isn't a straighforward way to do this. One work around would
be only providing a getter like Morten suggested. You could also use a
Field instead of a property and apply the readonly attribute to the field.
Not sure which will work with your exact scenario.

 

[Darren Oakey]

My favorite way is to have an interface for every class which is
changeable -

ie
interface ConstMyClass
{
int number {get;}
string value {get;}
ConstMyClass CombineWith( ConstMyClass);
...
}

then have your class implement that
ie
class MyClass : ConstMyClass
{
....
}

then most of the places you use it, you can define
void Fun1( ConstMyClass x )
{
}

and be 100% guaranteed that your object isn't going to be manipulated.

 

[Jon Skeet]

My favorite way is to have an interface for every class which is
changeable -

ie
interface ConstMyClass
{
int number {get;}
string value {get;}
ConstMyClass CombineWith( ConstMyClass);
...
}

then have your class implement that
ie
class MyClass : ConstMyClass
{
...
}

then most of the places you use it, you can define
void Fun1( ConstMyClass x )
{
}

and be 100% guaranteed that your object isn't going to be manipulated.

Unfortunately it doesn't, actually - because the client can always
check whether or not the instance is *actually* an instance of MyClass,
cast it, and then manipulate it.

What you *can* do is have a wrapper which *contains* an instance of
MyClass, and delegates read access to it, eg:

class ConstMyClass
{
MyClass target;

public ConstMyClass (MyClass target)
{
this.target = target;
}

public int Number
{
get { return target.Number; }
}
}

etc