C# Snippets

Declare an async method using async/await (C# 5.0+)

public async Task<${1:string}> ${2:GetDataAsync}()
{
    var result = await ${3:FetchAsync()};
    return result;
}

Initialize a collection using the bracket syntax (C# 12.0+)

${1:int}[] ${2:values} = [${3:1, 2, 3}];

Define an interface with a default method implementation (C# 8.0+)

public interface ${1:IFormatter}
{
    string ${2:Format}(double value) => value.ToString("0.00");
}

Define a static extension method class (C# 3.0+)

public static class ${1:StringExtensions}
{
    public static bool ${2:IsNullOrEmpty}(this string ${3:value}) => string.IsNullOrEmpty(${3:value});
}

Declare a file-scoped namespace to reduce indentation (C# 10.0+)

namespace ${1:MyApp.Services};

public class ${2:OrderService}
{
}

Declare Func and Action delegate variables (C# 3.0+)

Func<int, int, int> ${1:add} = (a, b) => a + b;
Action<string> ${2:print} = message => Console.WriteLine(message);

Declare global using directives for project-wide imports (C# 10.0+)

global using System;
global using System.Collections.Generic;
global using System.Linq;

Declare a class with init-only property setters (C# 9.0+)

public class ${1:Point}
{
    public int X { get; init; }
    public int Y { get; init; }
}

Declare a lambda expression using Func delegate (C# 3.0+)

Func<int, bool> ${1:isEven} = ${2:n} => ${3:n % 2 == 0};

Query a collection using LINQ method syntax (C# 3.0+)

var ${1:results} = ${2:items}
    .Where(x => x.IsActive)
    .OrderBy(x => x.Name)
    .Select(x => x.Name)
    .ToList();

Match sequences using list patterns in a switch expression (C# 11.0+)

string ${1:label} = ${2:values} switch
{
    [var first, ..] => $"Starts with {first}",
    [] => "Empty",
    _ => "Other"
};

Declare and null-check a nullable reference type variable (C# 8.0+)

string? ${1:name} = ${2:GetName()};
if (${1:name} is not null)
{
    Console.WriteLine(${1:name}.Length);
}

Use an out parameter with TryParse (C# 7.0+)

if (int.TryParse(${1:input}, out int ${2:value}))
{
    Console.WriteLine(${2:value});
}

Match a value against a type or property pattern (C# 7.0+)

if (${1:obj} is ${2:string} ${3:s})
{
    $0
}

Declare a class with a primary constructor (C# 12.0+)

public class ${1:OrderService}(${2:ILogger} ${3:logger})
{
    public void Process()
    {
        ${3:logger}.LogInformation("Processing...");
    }
}

Declare a raw string literal for multi-line text (C# 11.0+)

var ${1:json} = """
    {
        "name": "value"
    }
    """;

Declare an immutable record with positional properties (C# 9.0+)

public record ${1:Person}(${2:string} ${3:FirstName}, ${4:string} ${5:LastName});

Class with required init-only properties (C# 11.0+)

public class ${1:UserProfile}
{
    public required string ${2:Name} { get; init; }
    public required string ${3:Email} { get; init; }
}

Use ReadOnlySpan for allocation-free string slicing (C# 7.2+)

ReadOnlySpan<char> ${1:text} = "Hello, World!".AsSpan();
ReadOnlySpan<char> ${2:hello} = ${1:text}.Slice(0, 5);

Define an interface with a static abstract operator (C# 11.0+)

public interface ${1:IAddable}<${2:TSelf}> where ${2:TSelf} : ${1:IAddable}<${2:TSelf}>
{
    static abstract ${2:TSelf} operator +(${2:TSelf} left, ${2:TSelf} right);
}

Embed expressions in a string using $ prefix (C# 6.0+)

var message = $"${1:Hello}, {${2:name}}!";

Concise switch expression returning a value (C# 8.0+)

var ${1:result} = ${2:value} switch
{
    ${3:1} => "${4:one}",
    ${5:2} => "${6:two}",
    _ => "${7:other}"
};

Write a program using top-level statements without a Main method (C# 9.0+)

using System;

Console.WriteLine("${1:Hello, World!}");

Return and deconstruct a named tuple (C# 7.0+)

(${1:double} ${2:X}, ${3:double} ${4:Y}) ${5:GetPoint}()
{
    return (${6:0.0}, ${7:0.0});
}

var (${8:x}, ${9:y}) = ${5:GetPoint}();

Declare a disposable resource that is automatically disposed at end of scope (C# 8.0+)

using var ${1:resource} = new ${2:StreamReader}(${3:"file.txt"});

Declare a local variable using type inference (C# 3.0+)

var ${1:name} = ${2:value};