Convert Double to Hex String

VB.NET

Public Function Double2Hex(value As Double) As String

    Return String.Concat(BitConverter.GetBytes(value).Reverse().Select(Function(b) b.ToString("X2")))

End Function

Public Function Hex2Double(value As String) As Double

    Dim valueLength = value.Length >> 1
    Dim a(valueLength - 1) As Byte

    For i = 0 To valueLength - 1
        a(valueLength - 1 - i) = Convert.ToByte(value.Substring(i * 2, 2), 16)
    Next

    Return BitConverter.ToDouble(a, 0)

End Function