{"id":34694,"date":"2021-12-06T09:00:00","date_gmt":"2021-12-06T08:00:00","guid":{"rendered":"https:\/\/mmguide.nl\/?p=34694"},"modified":"2022-01-10T15:51:06","modified_gmt":"2022-01-10T14:51:06","slug":"tech-update-december","status":"publish","type":"post","link":"https:\/\/mmguide.nl\/nl\/tech-update-december\/","title":{"rendered":"Tech Update December"},"content":{"rendered":"
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This tech update will be very techy, readers beware! Earlier this month .NET 6 was released, offering a boatload of new features. I picked some personal favorite features to dive into, mostly from C# 10. There are way too many new features to highlight in this blog, so I included a link to Microsoft\u2019s announcement blog and a .NET deep dive video by Microsoft below.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Index operator support for ElementAt<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Consider the following collection:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var<\/span> collection = new List<int><\/span> { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };<\/p>

\u00a0<\/p>

\/\/ To get the 4th<\/sup> index in this collection<\/span><\/p>

var<\/span> fourth = collection.ElementAt(4);<\/p>

\u00a0<\/p>

\/\/ To get the 4th<\/sup> index from the end in this collection, you can now use the index operator ^<\/span><\/p>

var<\/span> fourthFromEnd = collection.ElementAt(^4);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Read more about index operators and ranges here<\/a>.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Multiple enumeration<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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public static bool<\/span> TryGetNonEnumeratedCount<TSource> (this<\/span> System.Collections.Generic.IEnumerable<TSource> source, out int<\/span> count);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Consider the following block of code:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var <\/span>collection1 = new<\/span> [] { “foo”<\/span> };<\/p>

var<\/span> collection2 = new<\/span> [] { “bar”<\/span> };<\/p>

\u00a0<\/p>

IEnumerable<string<\/span>> collections = collection1.Concat(collection2);<\/p>

\u00a0<\/p>

var<\/span> count = collections.Count();<\/p>

var<\/span> orderCollections = collections.OrderBy(c => c);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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When doing that count, you enumerate through the collection to count the number of elements in the collection. You then follow up with a sorting algorithm to order the elements, effectively enumerating through the collection again<\/em>. This is not effective, but .NET 6 gives you a way to optimize this.<\/p>

When in need of a count, you now can do the following:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var<\/span> count = 0;<\/p>

\u00a0<\/p>

if (collections.TryGetNonEnumeratedCount(out<\/span> count))<\/p>

{<\/p>

\u00a0\u00a0\u00a0 \/\/do something<\/span><\/p>

}<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Now we don\u2019t have forced enumeration, which can save resources in certain situations.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Enumarable.Chunk<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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public static<\/span> System.Collections.Generic.IEnumerable<TSource[]> Chunk (this<\/span> System.Collections.Generic.IEnumerable source, int<\/span> size);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Previously, when you wanted to divide a collection into chunks, you had to create your own function to do so. It would look something like this.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var<\/span> collection = new<\/span> List<int<\/span>> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };<\/p>

\u00a0<\/p>

var<\/span> chunkie = ChunkMe<int<\/span>>(collection, 3);<\/p>

\/\/ { 1, 2, 3}<\/span><\/p>

\/\/ { 4, 5, 6}<\/span><\/p>

\/\/ { 7, 8, 9}<\/span><\/p>

\u00a0<\/p>

IEnumerable ChunkMe(IEnumerable source, int<\/span> chunkSize)<\/p>

{<\/p>

return<\/span> source<\/p>

.Select((x, i) => new<\/span> { Index = i, Value = x })<\/p>

.GroupBy(x => x.Index \/ chunkSize)<\/p>

.Select(x => x.Select(y => y.Value));<\/p>

}<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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In .NET 6 you simple call the Chunk() function on a collection.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var <\/span>collection = new<\/span> List<int<\/span>> { 1, 2, 3, 4, 5, 6, 7, 8, 9 };<\/p>

\u00a0<\/p>

var<\/span> chunkie = collection.Chunk(3);<\/p>

\/\/ { 1, 2, 3}<\/span><\/p>

\/\/ { 4, 5, 6}<\/span><\/p>

\/\/ { 7, 8, 9}<\/span><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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DateOnly and TimeOnly Types<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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public struct<\/span> DateOnly : IComparable, IComparable, IEquatable, ISpanFormattable<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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public struct<\/span> TimeOnly : IComparable, IComparable, IEquatable, ISpanFormattable<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Since forever we have been using the DateTime type in .NET. This is usually fine, but now and then you see these gremlins creep in when trying to get a date or a time from a DateTime. DateOnly and TimeOnly should prevent\u00a0 that when you are looking for just a time or a date.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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DateOnly date = DateOnly.MinValue;<\/p>

Console.WriteLine(date);<\/p>

\/\/ Output: 01-01-0001 (no time indication)<\/span><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Where DateOnly is pretty straightforward, TimeOnly has some pretty cool features.<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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TimeOnly time = TimeOnly.MinValue;<\/p>

Console.WriteLine(time);<\/p>

\/\/ Output: 00:00<\/span><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Use AddHours() to add time:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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TimeOnly time2 = time.AddHours(3);<\/p>

Console.WriteLine(time2);<\/p>

\/\/ Output: 03:00<\/span><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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IsBetween is another nifty feature:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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TimeOnly start = TimeOnly.Parse(“14:00”<\/span>);<\/p>

TimeOnly end = TimeOnly.Parse(“18:00”<\/span>);<\/p>

Console.WriteLine(TimeOnly.Parse(“16:00”<\/span>).IsBetween(start, end));<\/p>

\/\/ Output: True<\/span><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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MinBy, MaxBy, By..By..By..<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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public static<\/span> TSource? MinBy<TSource,TKey> (this<\/span> System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TSource>? comparer);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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public static<\/span> TSource? MaxBy<TSource,TKey> (this<\/span> System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<Func<TSource,TKey>> keySelector, System.Collections.Generic.IComparer<TSource>? comparer);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Docs<\/a><\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Previously, when you wanted to order a collection by, let’s say, a year. You had to do something along the lines of:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var<\/span> events = new<\/span>[]<\/p>

{<\/p>

\u00a0\u00a0\u00a0 new<\/span> Event(“Moonlanding”<\/span>, 1969),<\/p>

\u00a0\u00a0\u00a0 new<\/span> Event(“Invention of Television”<\/span>, 1925),<\/p>

\u00a0\u00a0\u00a0 new<\/span> Event(“Birth of the Internet”<\/span>, 1965)<\/p>

};<\/p>

\u00a0<\/p>

var<\/span> earliest = events.OrderBy(e => e.Year).FirstOrDefault();<\/p>

var<\/span> latest = events.OrderBy(e => e.Year).FirstOrDefault();<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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In .NET 6 you can do:<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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var<\/span> earliest = events.MinBy(e => e.Year);<\/p>

var<\/span> latest = events.MaxBy(e => e.Year);<\/p>\t\t\t\t\t\t\t<\/div>\r\n\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Other new “By” functions:<\/p>