Friday, March 18, 2011

ScreenGrabber and Github

The screenshotting program that I've been working on for so long is finally nearing completion. I've updated it to include a lot of neat features, and I've gotten rid of the stupid way that I was capturing screen areas, replaced with being able to draw a box around what you want.

It's too big to just post the code here, and I really can't upload anything here anyway. So I'll use this to also mention that I have a Github account. My repos are here:

ScreenGrabber has my screen shot program.

Download it, build it, and break it for me so I can make it better!

Also, if anyone wants to make any better icons for me, I'd love them, since mine suck.

Thursday, March 10, 2011

New Extension Method for IList: SafeInsert

IList.Insert takes an index and a value, and attempts to insert that value at that index, pushing all following values out to the next index. Of course, that index must exist to do the insert.

I figured, why? If I want to move something to position 50, but there are only 5 values in the List, is it reasonable to assume that I want it to go to the last spot, since 50 isn't available? Maybe. Especially in the case where I'm presenting the user a grid, and allowing them to change a row's index manually. I'd rather not bother testing the number they enter, and just assume that if they put an index greater than exists that they want it to be inserted at the end.

This really isn't challenging code or anything, but it's useful, and the first time I thought of it, so I'll share:

public static void SafeInsert<t>(this IList<t> list, int index, T val){
    if (index < 0)
        list.Insert(0, val);
    else if (index > list.Count)
        list.Insert(list.Count, val);
        list.Insert(index, val);

Friday, February 11, 2011

Extension methods: For<T> and ForEach<T>

I noticed that List has a method called ForEach, that takes an Action and applies it to all elements in the collection. This is not an extension method, it's part of List.

I wondered why it's not part of the LINQ Extension methods. The best I could come up with was that IEnumerables can be infinite, so a non-terminable ForEach would cause problems. Of course, we can do these with standard foreach loops, so I see no harm in including it if you know what you're getting into. Also, it should be possible to provide a terminator clause to exit the foreach loop as a Func.

With that said, I also felt the need to be able to simulate a simple for loop. An indexed-foreach, if you will. So here are three extension methods I've come up with:

public static void For<T>(this IEnumerable<T> items, Action<int, T> action) {
    for (int i = 0; i < items.Count(); i++)
        action(i, items.ElementAt(i));

public static void ForEach<T>(this IEnumerable<T> items, Action<T> action) {
    foreach (T item in items)

public static void ForEach<T>(this IEnumerable<T> items, Action<T> action, Func<T, bool> breakWhen) {
    foreach (T item in items) {
        if (breakWhen(item))

Here's an example of use:

var numbers = Enumerable.Range(10, 10);
numbers.For((i, x) => Console.WriteLine("Index: {0}, Value: {1}", i, x));
numbers.ForEach(x => Console.WriteLine(x));
var allReal = Extensions.Real(0);
allReal.ForEach(x => Console.WriteLine(x), x => x > 9);

Extensions.Real(0) is just a method that returns an IEnumerable that starts at 0 and counts up. There's no exit condition, so if you tried to iterate through the whole thing, it'd just go until it hit an integer overflow. But it shows we can provide an exit condition for a ForEach loop.