C# Unix 时间戳代码片段

C# timestamp basics

Modern C# should use DateTimeOffset for Unix timestamp work. DateTimeOffset.UtcNow.ToUnixTimeSeconds() returns Unix seconds, and ToUnixTimeMilliseconds() returns JavaScript-compatible milliseconds.

Converting DateTimeOffset values

Use FromUnixTimeSeconds or FromUnixTimeMilliseconds to convert epoch values into DateTimeOffset. Keep storage in UTC and format with the round-trip O format when you need an ISO 8601 string.

C# production notes

DateTimeOffset is usually safer than DateTime for timestamp work because it keeps an offset attached to the value. Store UTC instants for comparisons and persistence, then convert to a local timezone only for display. Be careful when integrations say epoch time without naming seconds or milliseconds.

• Use DateTimeOffset.UtcNow.ToUnixTimeSeconds() for standard Unix seconds
• Use ToUnixTimeMilliseconds() for JavaScript-compatible values
• Use FromUnixTimeSeconds() when reading API values documented as seconds
• Use the O format for round-trip ISO 8601 strings in logs and JSON

Frequently checked C# details

Should timestamp code use DateTime or DateTimeOffset?

Prefer DateTimeOffset for Unix timestamp work because it preserves offset context. It also exposes direct Unix seconds and milliseconds helpers.

What does the O format do?

The O format writes a round-trip ISO 8601 value. It is useful for logs, JSON, and tests where the exact instant should survive parsing.

How do I verify a C# conversion?

Convert the value back with DateTimeOffset.FromUnixTimeSeconds or FromUnixTimeMilliseconds, format it with O, and compare that UTC output with your expected timestamp before saving the value.