StringBuilderでintをAppendしたときにToStringされる環境用

StringBuilderUtil.cs

public static class StringBuilderUtil
{
    public static void AppendInt(System.Text.StringBuilder sb, int value)
    {
        int n = value;
        if (n < 0)
        {
            sb.Append('-');
            n *= -1;
        }
        int k = 1;
        int m = n;
        while (m / 10 != 0)
        {
            m /= 10;
            k *= 10;
        }
        while (k != 0)
        {
            int d = n / k;
            n = n - d * k;
            k /= 10;
            char c = (char)('0' + d);
            sb.Append(c);
        }
    }
}