整数到十六进制:

Int a = 72; 控制台。WriteLine(“{0:X}”);

十六进制到整型:

int b = 0xB76; Console.WriteLine (b);

就像@Joel C一样，我认为这是AB问题。 有一个现有的算法，我认为更适合的需求，如所描述的，那就是uuencode，我相信它有许多公共领域的实现，也许调整以消除看起来非常类似于0/O的字符。很可能产生明显更短的字符串。我认为这就是URL缩短者使用的。

// Store integer 182
int intValue = 182;
// Convert integer 182 as a hex in a string variable
string hexValue = intValue.ToString("X");
// Convert the hex string back to the number
int intAgain = int.Parse(hexValue, System.Globalization.NumberStyles.HexNumber);

从http://www.geekpedia.com/KB8_How-do-I-convert-from-decimal-to-hex-and-hex-to-decimal.html

提示(来自评论):

使用. tostring ("X4")获得前导0的4位数字，或使用. tostring ("X4")获得小写十六进制数字(同样用于更多数字)。

尝试以下将其转换为十六进制

public static string ToHex(this int value) {
  return String.Format("0x{0:X}", value);
}

然后再回来

public static int FromHex(string value) {
  // strip the leading 0x
  if ( value.StartsWith("0x", StringComparison.OrdinalIgnoreCase)) {
    value = value.Substring(2);
  }
  return Int32.Parse(value, NumberStyles.HexNumber);
}

在我找到这个答案之前，我创建了自己的解决方案，将int转换为十六进制字符串并返回。毫不奇怪，它比.net解决方案快得多，因为代码开销更少。

        /// <summary>
        /// Convert an integer to a string of hexidecimal numbers.
        /// </summary>
        /// <param name="n">The int to convert to Hex representation</param>
        /// <param name="len">number of digits in the hex string. Pads with leading zeros.</param>
        /// <returns></returns>
        private static String IntToHexString(int n, int len)
        {
            char[] ch = new char[len--];
            for (int i = len; i >= 0; i--)
            {
                ch[len - i] = ByteToHexChar((byte)((uint)(n >> 4 * i) & 15));
            }
            return new String(ch);
        }

        /// <summary>
        /// Convert a byte to a hexidecimal char
        /// </summary>
        /// <param name="b"></param>
        /// <returns></returns>
        private static char ByteToHexChar(byte b)
        {
            if (b < 0 || b > 15)
                throw new Exception("IntToHexChar: input out of range for Hex value");
            return b < 10 ? (char)(b + 48) : (char)(b + 55);
        }

        /// <summary>
        /// Convert a hexidecimal string to an base 10 integer
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        private static int HexStringToInt(String str)
        {
            int value = 0;
            for (int i = 0; i < str.Length; i++)
            {
                value += HexCharToInt(str[i]) << ((str.Length - 1 - i) * 4);
            }
            return value;
        }

        /// <summary>
        /// Convert a hex char to it an integer.
        /// </summary>
        /// <param name="ch"></param>
        /// <returns></returns>
        private static int HexCharToInt(char ch)
        {
            if (ch < 48 || (ch > 57 && ch < 65) || ch > 70)
                throw new Exception("HexCharToInt: input out of range for Hex value");
            return (ch < 58) ? ch - 48 : ch - 55;
        }

计时代码:

static void Main(string[] args)
        {
            int num = 3500;
            long start = System.Diagnostics.Stopwatch.GetTimestamp();
            for (int i = 0; i < 2000000; i++)
                if (num != HexStringToInt(IntToHexString(num, 3)))
                    Console.WriteLine(num + " = " + HexStringToInt(IntToHexString(num, 3)));
            long end = System.Diagnostics.Stopwatch.GetTimestamp();
            Console.WriteLine(((double)end - (double)start)/(double)System.Diagnostics.Stopwatch.Frequency);

            for (int i = 0; i < 2000000; i++)
                if (num != Convert.ToInt32(num.ToString("X3"), 16))
                    Console.WriteLine(i);
            end = System.Diagnostics.Stopwatch.GetTimestamp();
            Console.WriteLine(((double)end - (double)start)/(double)System.Diagnostics.Stopwatch.Frequency);
            Console.ReadLine(); 
        }

结果:

Digits : MyCode : .Net
1 : 0.21 : 0.45
2 : 0.31 : 0.56
4 : 0.51 : 0.78
6 : 0.70 : 1.02
8 : 0.90 : 1.25

打印十六进制值的整数与零填充(如果需要):

int intValue = 1234;

Console.WriteLine("{0,0:D4} {0,0:X3}", intValue); 

https://learn.microsoft.com/en-us/dotnet/standard/base-types/how-to-pad-a-number-with-leading-zeros