c# - Extend a type with customized class

Question

I'm wondering something. Instead of writing String.Format("{0:X}", num); to convert numbers to hex. Is there a way where i could extend string directly so that i could simply write num.ToHex(); instead?

Answer 1

您可以创建扩展方法：

public static class IntExtensions
{
    public static string ToHex(this int source)
    {
        return string.Format("{0:X}", source);
    }
}

像这样执行：

string hexNum = 1234.ToHex();

Answer 2

它被称为扩展方法。但是，它应该设置为数字类型，以允许{0:X}字符串格式：

public static class Extensions
{
    public static string ToHex(this int source)
    {
        return string.Format("{0:X}", source);
    }
}