Passing a method as a parameter

[hardieca@hotmail.com]

Hello,

I'm creating a toolbox of useful functions, and I've added a function
that recursively drills down through a file system searching for files.
I've created a number of variations of this function, and I imagine
I'll continue to have use for it.

What I would like to do is create a version that will take a method as
a parameter and invoke it as it traverses my file system path. Here is
some pseudo-code that will hopefully illustrate what I'm trying to do:

public class Toolbox{
public void (string startDirectory, Method myMethod) fileDriller{
foreach (string f in Directory.GetFi les(startDirect ory){
myMethod(f);
}
foreach (string d in Directory.GetDi rectories(start Directory){
fileDriller(d, myMethod);
}
}
}

So let's say I wanted to determine the length of each filename in a
directory of interest and every subdirectory:

public void lengthOfFileNam e(string fileName){
Console.write(f ileName.Length. toString());
}

static void Main(){
Toolbox tb = new Toolbox();
tb.fileDriller( "C:\\somedi r", lengthOfFileNam e);
}

I tried passing a MethodInfo object, but I'm running into issues
because, I believe, it's an abstract class. If anyone has any idea how
I would accomplish this, please let me know!

Regards,

Chris

[Dustin Campbell]

Re: Passing a method as a parameter

If the signature of your method is known, use a delegate:

public void delegate FileMethod(stri ng fileName);

public void FileDriller(str ing startDirectory, FileMethod myMethod)
{
foreach (string f in Directory.GetFi les(startDirect ory))
myMethod(f);

foreach (string d in Directory.GetDi rectories(start Directory))
FileDriller(d, myMethod);
}

Dustin Campbell
Developer Express Inc.

[Chris Fulstow]

Re: Passing a method as a parameter

You could do this using delegates, or using the "strategy" design
pattern.

Delegates

http://msdn2.microsoft.com/en-us/library/ms173171(VS.80).aspx

Strategy pattern

http://www.dofactory.com/Patterns/PatternStrategy.aspx

Good luck!

hardi...@hotmai l.com wrote:

Hello,
>
I'm creating a toolbox of useful functions, and I've added a function
that recursively drills down through a file system searching for files.
I've created a number of variations of this function, and I imagine
I'll continue to have use for it.
>
What I would like to do is create a version that will take a method as
a parameter and invoke it as it traverses my file system path. Here is
some pseudo-code that will hopefully illustrate what I'm trying to do:
>
public class Toolbox{
public void (string startDirectory, Method myMethod) fileDriller{
foreach (string f in Directory.GetFi les(startDirect ory){
myMethod(f);
}
foreach (string d in Directory.GetDi rectories(start Directory){
fileDriller(d, myMethod);
}
}
}
>
So let's say I wanted to determine the length of each filename in a
directory of interest and every subdirectory:
>
public void lengthOfFileNam e(string fileName){
Console.write(f ileName.Length. toString());
}
>
static void Main(){
Toolbox tb = new Toolbox();
tb.fileDriller( "C:\\somedi r", lengthOfFileNam e);
}
>
I tried passing a MethodInfo object, but I'm running into issues
because, I believe, it's an abstract class. If anyone has any idea how
I would accomplish this, please let me know!
>
Regards,
>
Chris