{"id":7745,"date":"2016-08-30T10:00:07","date_gmt":"2016-08-30T17:00:07","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/visualstudio\/?p=7745"},"modified":"2019-02-14T15:27:46","modified_gmt":"2019-02-14T23:27:46","slug":"new-c-7-0-features-in-vs15-preview-4","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/visualstudio\/new-c-7-0-features-in-vs15-preview-4\/","title":{"rendered":"New C# 7.0 features in Visual Studio “15” Preview 4"},"content":{"rendered":"

Over the past couple of previews, new C# language features have been trickling in, but Preview 4<\/a> marks a point where the majority of C# 7.0 are now available.<\/p>\n

Here’s a code sample that uses a good number of these features, and that works in Preview 4 today:<\/p>\n

\r\n
class<\/span><\/span><\/span> <\/span><\/span><\/span>Program<\/span><\/span><\/span><\/p>\r\n
{<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>static<\/span><\/span> <\/span><\/span>void<\/span><\/span> <\/span><\/span>Main<\/span><\/span>(<\/span><\/span>string[]<\/span><\/span><\/span> args)<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span>{<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>object<\/span><\/span><\/span>[] numbers =<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>{ 0b1, 0b10, <\/span><\/span><\/span>new<\/span><\/span> <\/span><\/span>object<\/span><\/span>[] { 0b100, 0b1000 },\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ binary literals<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>0b1_0000, 0b10_0000 };\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ digit separators<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>var<\/span><\/span> (sum, count) = Tally(numbers);\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ deconstruction<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>WriteLine($<\/span><\/span><\/span>\"Sum: {sum}, Count: {count}\"<\/span><\/span><\/span>);<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span>}<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>static<\/span><\/span> (<\/span><\/span>int<\/span><\/span> sum, <\/span><\/span>int<\/span><\/span> count) <\/span><\/span>Tally<\/span><\/span>(<\/span><\/span>object[]<\/span><\/span><\/span> values)\u00a0\u00a0\u00a0\u00a0 <\/span>\/\/ tuple types<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span>{<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>var<\/span><\/span> r = (s: <\/span><\/span>0<\/span><\/span>, c: <\/span><\/span>0<\/span><\/span>);\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ tuple literals<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>void<\/span><\/span> Add(<\/span><\/span>int<\/span><\/span> s, <\/span><\/span>int<\/span><\/span> c) { r = (r.s + s, r.c + c); } <\/span><\/span><\/span>\/\/ local functions<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>foreach<\/span><\/span> (<\/span><\/span>var<\/span><\/span> v <\/span><\/span>in<\/span><\/span><\/span> values)<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>{<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>switch<\/span><\/span> (v)\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ switch on any value<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>{<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>case<\/span><\/span> <\/span><\/span>int<\/span><\/span> i:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ type patterns<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Add(i, <\/span><\/span><\/span>1<\/span><\/span><\/span>);<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>break<\/span><\/span><\/span>;<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>case<\/span><\/span> <\/span><\/span>object<\/span><\/span>[] a <\/span><\/span>when<\/span><\/span> a.Length > <\/span><\/span>0<\/span><\/span>:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>\/\/ case conditions<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>var<\/span><\/span><\/span> t = Tally(a);<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>Add(t.sum, t.count);<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>break<\/span><\/span><\/span>;<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>}<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span>}<\/span><\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/span><\/span><\/span><\/span>return<\/span><\/span><\/span> r;<\/span><\/span><\/span><\/p>\r\n
\u00a0\u00a0\u00a0 <\/span><\/span>}<\/span><\/span><\/span><\/span><\/p>\r\n
}<\/span><\/span><\/span><\/span><\/p>\r\n
<\/p>\r\n<\/pre>\n
For a full write-up about tuples, deconstruction, pattern matching, local functions, and the rest of C# 7.0, head over to the .NET Blog<\/a>.<\/p>\n
Earlier versions of some of these features were shown at Build 2016<\/a>.<\/p>\n
Happy hacking!<\/p>\n\n\n\n
<\/td>\nMads Torgersen<\/strong>, C# Language Program Manager\n@MadsTorgersen<\/a><\/p>\n
Mads leads the design of the C# language. During his 11 years at Microsoft he also contributed to Typescript, Roslyn, Visual Basic, and LINQ. Before that he was a professor at Aarhus University, doing research on programming languages and type systems.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"
Over the past couple of previews, new C# language features have been trickling in, but Preview 4 marks a point where the majority of C# 7.0 are now available. Here’s a code sample that uses a good number of these features, and that works in Preview 4 today: class Program { \u00a0\u00a0\u00a0 static void Main(string[] […]<\/p>\n","protected":false},"author":13,"featured_media":255385,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[155],"tags":[237,1383,585,125,653],"class_list":["post-7745","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-visual-studio","tag-net","tag-c","tag-r","tag-typescript","tag-visual-basic"],"acf":[],"blog_post_summary":"
Over the past couple of previews, new C# language features have been trickling in, but Preview 4 marks a point where the majority of C# 7.0 are now available. Here’s a code sample that uses a good number of these features, and that works in Preview 4 today: class Program { \u00a0\u00a0\u00a0 static void Main(string[] […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/posts\/7745","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/comments?post=7745"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/posts\/7745\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/media\/255385"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/media?parent=7745"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/categories?post=7745"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/visualstudio\/wp-json\/wp\/v2\/tags?post=7745"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}