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Function within a method in C# / csharp / dotnet

I have since the birth of dotnet missed the possibility to have a function inside a function like one can in Pascal.

With lambda, and possibly Dotnet4(?) it is possible.  Below is a rather stupid example.

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internal int AddMaxWierd( int x, int y )
{
Func Max = delegate( int a ){
return Math.Min( a, 10 );
};

return Max(x) + Max(y);
}

If the inner method doesn’t have a return value, use “Action” instead of “Func”.
See how there is only one Manipulate method in the class, the other Manipulate method is hidden within the method.

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internal void Manipulate( CustomerList Customer customers )
{
Action<Customer> Manipulate = delegate( Customer customer )
{
// do stuff...
};

foreach( var customer in customers ){
Manipulate( customer );
}

}

 

Update:

In C#7 it can be done. https://github.com/dotnet/roslyn/issues/6505

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This entry was posted on Monday, March 5th, 2012 at 20:49 and is filed under Code and Development. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

2 Responses to “Function within a method in C# / csharp / dotnet”

  1. Mike Calvert says:
    2012-03-11 at 07:22

    Hey man,

    You could probably use the Emitter to generate a method at run time and execute it, or just use the method info of a method. What exactly is the point here?

    Reply
  2. selfelected says:
    2012-03-13 at 23:12

    Emit takes a string with code IIRC. This means no debug possibilities and no intellisense.
    MethodInfo takes a reference to a method that already has to be somewhere.

    The solution I presented above makes a function inside another function without any tricks.

    Reply

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