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20180927
Environment.​Exit​Code  Property
Gets or sets the exit code of the process.

ref:
https://docs.microsoft.com/en-us/dotnet/api/system.environment.exitcode?redirectedfrom=MSDN&view=netframework-4.7.2#System_Environment_ExitCode


The following is a simple app named Double.exe that doubles an integer value passed to it as a command-line argument. The value assigns error codes to the ExitCode property to indicate error conditions. Note that you must add a reference to the System.Numerics.dll assembly to successfully compile the example. 

using System;
using System.Numerics;

public class Example
{
   private const int ERROR_BAD_ARGUMENTS = 0xA0;
   private const int ERROR_ARITHMETIC_OVERFLOW = 0x216;
   private const int ERROR_INVALID_COMMAND_LINE = 0x667;

   public static void Main()
   {
      string[] args = Environment.GetCommandLineArgs();
      if (args.Length == 1) {
         Environment.ExitCode = ERROR_INVALID_COMMAND_LINE;  
      }
      else {
         BigInteger value = 0;
         if (BigInteger.TryParse(args[1], out value))
            if (value <= Int32.MinValue || value >= Int32.MaxValue)
               Environment.ExitCode = ERROR_ARITHMETIC_OVERFLOW;
            else
               Console.WriteLine("Result: {0}", value * 2);

         else
            Environment.ExitCode = ERROR_BAD_ARGUMENTS;
      }
   }
}

The example can then be invoked from a batch file such as the following, which makes its error codes accessible by using the ERRORLEVEL command. 
echo off  
Double.exe %1  
If errorlevel 1639 goto NoArg   
if errorlevel 534 goto Overflow  
if errorlevel 160 goto BadArg  
if errorlevel 0 echo Completed Successfully   
goto :EOF  

:NoArg  
echo Missing argument  
goto :EOF  

: Overflow  
echo Arithmetic overflow  
goto :EOF  

:BadArg  
echo Invalid argument  
goto :EOF

The following shows some sample output produced by invoking the batch file. 
output:
>getdouble 123>echo offResult: 246Completed Successfully>getdouble 5912323109093>echo offArithmetic overflow>getdouble>echo offMissing argument>getdouble "a string">echo offInvalid argument


Note that code for Double.exe is identical in function to the following example, except that the former defines an entry point named Main that has no return value, whereas this example defines an entry point named Main that returns an integer. 

using System;
using System.Numerics;

public class Example
{
   private const int ERROR_SUCCESS = 0;
   private const int ERROR_BAD_ARGUMENTS = 0xA0;
   private const int ERROR_ARITHMETIC_OVERFLOW = 0x216;
   private const int ERROR_INVALID_COMMAND_LINE = 0x667;

   public static int Main()
   {
      string[] args = Environment.GetCommandLineArgs();
      if (args.Length == 1) {
         return ERROR_INVALID_COMMAND_LINE;  
      }
      else {
         BigInteger value = 0;
         if (BigInteger.TryParse(args[1], out value))
            if (value <= Int32.MinValue || value >= Int32.MaxValue)
               return ERROR_ARITHMETIC_OVERFLOW;
            else
               Console.WriteLine("Result: {0}", value * 2);

         else
            return ERROR_BAD_ARGUMENTS;
      }
      return ERROR_SUCCESS;
   }
}

Remarks

If the Main method returns void, you can use this property to set the exit code that will be returned to the calling environment. If Main does not return void, this property is ignored. The initial value of this property is zero. 


ＵWarning

The ExitCode property is a signed 32-bit integer. To prevent the property from returning a negative exit code, you should not use values greater than or equal to 0x80000000. 

Use a non-zero number to indicate an error. In your application, you can define your own error codes in an enumeration, and return the appropriate error code based on the scenario. For example, return a value of 1 to indicate that the required file is not present and a value of 2 to indicate that the file is in the wrong format. For a list of exit codes used by the Windows operating system, see System Error Codes in the Windows documentation.