Convert.ToInt64 Method (String, Int32) (System)

' Create a hexadecimal value out of range of the Long type.
Dim value As String = ULong.MaxValue.ToString("X")
' Call Convert.ToInt64 to convert it back to a number.
Try
   Dim number As Long = Convert.ToInt64(value, 16)
   Console.WriteLine("0x{0} converts to {1}.", value, number)
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value)
End Try   

// Create a hexadecimal value out of range of the long type.
string value = ulong.MaxValue.ToString("X");
// Use Convert.ToInt64 to convert it back to a number.
try
{
   long number = Convert.ToInt64(value, 16);
   Console.WriteLine("0x{0} converts to {1}.", value, number);
}   
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value);
}   

' Create a negative hexadecimal value out of range of the Long type.
Dim sourceNumber As ULong = ULong.MaxValue
Dim isSigned As Boolean = Math.Sign(sourceNumber.MinValue) = -1
Dim value As String = sourceNumber.ToString("X")
Dim targetNumber As Long
Try
   targetNumber = Convert.ToInt64(value, 16)
   If Not isSigned And ((targetNumber And &H8000000000) <> 0) Then
      Throw New OverflowException()
   Else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber)
   End If    
Catch e As OverflowException
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value)
End Try 
' Displays the following to the console:
'    Unable to convert '0xFFFFFFFFFFFFFFFF' to a long integer.     

// Create a negative hexadecimal value out of range of the Byte type.
ulong sourceNumber = ulong.MaxValue;
bool isSigned = Math.Sign(Convert.ToDouble(sourceNumber.GetType().GetField("MinValue").GetValue(null))) == -1;
string value = sourceNumber.ToString("X");
long targetNumber;
try
{
   targetNumber = Convert.ToInt64(value, 16);
   if (! isSigned && ((targetNumber & 0x80000000) != 0))
      throw new OverflowException();
   else 
      Console.WriteLine("0x{0} converts to {1}.", value, targetNumber);
}
catch (OverflowException)
{
   Console.WriteLine("Unable to convert '0x{0}' to a long integer.", value);
} 
// Displays the following to the console:
//    Unable to convert '0xFFFFFFFFFFFFFFFF' to a long integer.     

Module Example
   Public Sub Main()
      Dim hexStrings() As String = { "8000000000000000", "0FFFFFFFFFFFFFFF", _
                                     "f0000000000001000", "00A30", "D", "-13", "GAD" }
      For Each hexString As String In hexStrings
         Try
            Dim number As Long = Convert.ToInt64(hexString, 16)
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number)
         Catch e As FormatException
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.", _
                              hexString)
         Catch e As OverflowException
            Console.WriteLine("'{0}' is outside the range of an Int64.", hexString)
         Catch e As ArgumentException
            Console.WriteLine("'{0}' is invalid in base 16.", hexString)
         End Try
      Next                                            
   End Sub
End Module
' The example displays the following output:
'       Converted '8000000000000000' to -9,223,372,036,854,775,808.
'       Converted '0FFFFFFFFFFFFFFF' to 1,152,921,504,606,846,975.
'       'f0000000000001000' is outside the range of an Int64.
'       Converted '00A30' to 2,608.
'       Converted 'D' to 13.
'       '-13' is invalid in base 16.
'       'GAD' is not in the correct format for a hexadecimal number.

using System;

public class Example
{
   public static void Main()
   {
      string[] hexStrings = { "8000000000000000", "0FFFFFFFFFFFFFFF", 
                              "f0000000000001000", "00A30", "D", "-13", "GAD" };
      foreach (string hexString in hexStrings)
      {
         try {
            long number = Convert.ToInt64(hexString, 16);
            Console.WriteLine("Converted '{0}' to {1:N0}.", hexString, number);
         }
         catch (FormatException) {
            Console.WriteLine("'{0}' is not in the correct format for a hexadecimal number.",
                              hexString);
         }
         catch (OverflowException) {
            Console.WriteLine("'{0}' is outside the range of an Int64.", hexString);
         }
         catch (ArgumentException) {
            Console.WriteLine("'{0}' is invalid in base 16.", hexString);
         }
      }                                            
   }
}
// The example displays the following output:
//       Converted '8000000000000000' to -9,223,372,036,854,775,808.
//       Converted '0FFFFFFFFFFFFFFF' to 1,152,921,504,606,846,975.
//       'f0000000000001000' is outside the range of an Int64.
//       Converted '00A30' to 2,608.
//       Converted 'D' to 13.
//       '-13' is invalid in base 16.
//       'GAD' is not in the correct format for a hexadecimal number.