Code Forums - View Single Post - Delegates

ender · 03-03-2004, 11:38 AM

Here is my two bits to your question. Delegates (as I understand them) are just a typesafe way of passing pointers to member-functions/or functions in a type-safe way. Previously (in C++ and such) we just had a memory address, and we could call it with anything, which might not be what the function wants. Also, it doesn't hold any state information about the function. Delegates make it a type-safe way to call member functions.

A real world example besides an event handler would be anywhere you have used pointers to functions. For instance, I used them in a MUD I did for CS290 to handle how certain commands are processed. (Not 'events' but probably more like it than you wanted). For instance, someone typed "GO WEST" and I passed WEST to the function that was pointed to by the map of strings to functions. In this case, the function 'GO'. However, because of the uniformity of the arguments (I didn't pass any integers or anything) there wasn't any problems making sure there were sufficient arguments or types the the function because it was all standardized.

Another example of where you would use these are for dynamic validation of data. For instance, someone passes you a phone number, and depending on where you are located, or selected country, you can customize the function that will handle that phone number to validate it.

This is what I think, if I am wrong about what delegates are, please ignore/correct my post!

Hope this helps,
Ted Morse

03-03-2004, 11:38 AM	#2 (permalink)
ender Code Monkey Join Date: Mar 2003 Location: Evansville, IN Posts: 75	Delegates.... Here is my two bits to your question. Delegates (as I understand them) are just a typesafe way of passing pointers to member-functions/or functions in a type-safe way. Previously (in C++ and such) we just had a memory address, and we could call it with anything, which might not be what the function wants. Also, it doesn't hold any state information about the function. Delegates make it a type-safe way to call member functions. A real world example besides an event handler would be anywhere you have used pointers to functions. For instance, I used them in a MUD I did for CS290 to handle how certain commands are processed. (Not 'events' but probably more like it than you wanted). For instance, someone typed "GO WEST" and I passed WEST to the function that was pointed to by the map of strings to functions. In this case, the function 'GO'. However, because of the uniformity of the arguments (I didn't pass any integers or anything) there wasn't any problems making sure there were sufficient arguments or types the the function because it was all standardized. Another example of where you would use these are for dynamic validation of data. For instance, someone passes you a phone number, and depending on where you are located, or selected country, you can customize the function that will handle that phone number to validate it. This is what I think, if I am wrong about what delegates are, please ignore/correct my post! Hope this helps, Ted Morse __________________ while(1) fork();