在 C# 中转换十六进制值

Question

I am trying to display a two digit hex value into 16bit hex value. ie value =81 into 0x0000000000000081 . I have done the following code :

public long GetHexNumber(long d)
    {

        return long.Parse(d.ToString("X"), System.Globalization.NumberStyles.HexNumber);

    }

but the above code returns the same hex value ie 81 . Kindly help

Answer 1

Use Int64.ToString() like this:

    public string GetHexNumber(long d)
    {
        return d.ToString("X16");
    }

X ... for converting to hexString

16... for converting it to 16 digit string

If you want it to have a leading "0x" change it to:

    return "0x" + d.ToString("X16");

Answer 2

Let's start by providing a good test example, we want

1. Having an integer (eg 81 )
2. Treat is as if it's not decimal , but hexadecimal : 0x81 (we mechanically add 0x )
3. Obtain its value ( 0x81 == 129 )

Something like this:

 Value -> 0xValue 

If it's your case, the solution can be

 // static: we don't have any need in "this" instance
 public static long GetHexNumber(long value) {
   return Convert.ToInt64(value.ToString(), 16);
 } 

Test

 long test = 81;

 Console.WriteLine(81);
 // C# 6.0+ string interpolating
 // if don't use C# 6.0, put it as formatting: 
 // Console.WriteLine("{0:X16}", GetHexNumber(test)); 
 Console.WriteLine($"{GetHexNumber(test):X16}");