有没有更简单的方法来格式化C#中具有确切长度的字符串？

Question

我需要将字符串格式化为x个字符,但我格式化的值可以是任意长度.

"" => "          "
"New York" => "New York  "
"New York City" => "New York C"

目前,我这样做:

$"{(address.City.Substring(0, address.City.Length > 20 ? 20 : address.City.Length)),20}"

我这样做变得相当繁琐且容易出错:

var builder = new StringBuilder();
builder.AppendLine($"{(address.Street1.Substring(0, address.Street1.Length > 30 ? 30 : address.Street1.Length)),30}");
builder.AppendLine($"{(address.Street2.Substring(0, address.Street2.Length > 30 ? 30 : address.Street2.Length)),30}");
builder.AppendLine($"{(address.City.Substring(0, address.City.Length > 20 ? 20 : address.City.Length)),20}");
builder.AppendLine($"{(address.State.Substring(0, address.State.Length > 5 ? 5 : address.State.Length)),5}");
builder.AppendLine($"{(address.Zip.Substring(0, address.Zip.Length > 10 ? 10 : address.Zip.Length)),10}");
var result = builder.ToString();

而且我还需要做大约30件其他事情.如果有这样的事情,那将是非常好的:

address.City.SubstringExact(0, 20)

Answer 1

你可以只添加一个扩展方法到字符串,这将为你做到这一点:

public static class StringExtensions
{
    public static string ToLength(this string self, int length)
    {
        if(self == null)
           return null;

        return self.Length > length ? self.Substring(0, length) : self.PadRight(length);
    }
}