Invalid dll action. Installer shows error: Wizard ended prematurely

I am using a dll to copy one directory to another as part of wix. Since in the test program I am using the following code, which works fine with the console application .

Backup.dll

namespace WiXTutorial.Samples
{
    using System;
    using System.Collections.Generic;
    using System.IO;
    using Microsoft.Deployment.WindowsInstaller;

    public class SampleCheckPID
    {
        [CustomAction]
        public static ActionResult Backup(Session session)
        {
            DirectoryCopy(@"D:\share", @"D:\sharecopy", true);
            return ActionResult.Success;
        }

        private static void DirectoryCopy(
            string sourceDirName, string destDirName, bool copySubDirs)
        {
            DirectoryInfo dir = new DirectoryInfo(sourceDirName);
            DirectoryInfo[] dirs = dir.GetDirectories();

            // If the source directory does not exist, throw an exception.
            if (!dir.Exists)
            {
                throw new DirectoryNotFoundException(
                    "Source directory does not exist or could not be found: "
                    + sourceDirName);
            }

            // If the destination directory does not exist, create it.
            if (!Directory.Exists(destDirName))
            {
                Directory.CreateDirectory(destDirName);
            }


            // Get the file contents of the directory to copy.
            FileInfo[] files = dir.GetFiles();

            foreach (FileInfo file in files)
            {
                // Create the path to the new copy of the file.
                string temppath = Path.Combine(destDirName, file.Name);

                // Copy the file.
                file.CopyTo(temppath, false);
            }

            // If copySubDirs is true, copy the subdirectories.
            if (copySubDirs)
            {

                foreach (DirectoryInfo subdir in dirs)
                {
                    // Create the subdirectory.
                    string temppath = Path.Combine(destDirName, subdir.Name);

                    // Copy the subdirectories.
                    DirectoryCopy(subdir.FullName, temppath, copySubDirs);
                }
            }
        }
    }
}

      

        
        
        
      

    

Product.wxs

<CustomAction Id='Backup' DllEntry='Backup' BinaryKey='CheckPID' Execute='immediate' Return='check'  />

<InstallExecuteSequence>
    <Custom Action='Backup' After='InstallFiles' />
</InstallExecuteSequence>


<Binary Id='CheckPID' SourceFile='D:\Nirvana\Installer\Backup\Backup\bin\Debug\Backup.dll' />

      

        
        
        
      

    

Above the line of code builds fine as mentioned in the link - http://wixtoolset.org/documentation/manual/v3/wixdev/extensions/authoring_custom_actions.html

and

- https://www.firegiant.com/wix/tutorial/events-and-actions/how-to-manage/

But when I install the application, it shows the error: Wizard finished prematurely

This is my log exit

Error: could not load custom action class WiXTutorial.Samples.SampleCheckPID from assembly: CheckPID System.BadImageFormatException: 
Could not load file or assembly 'CheckPID' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded. 
File name: 'CheckPID' at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) 
    at System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) at System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) at System.AppDomain.Load(String assemblyString) 
    at Microsoft.Deployment.WindowsInstaller.CustomActionProxy.GetCustomActionMethod(Session session, String assemblyName, String className, String methodName)

WRN: Assembly binding logging is turned OFF. To enable assembly bind failure logging, set the registry value (DWORD) to 1. 
Note: There is some performance penalty associated with assembly bind failure logging. To turn this feature off, remove the registry value .

CustomAction Backup returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox) 
Action ended 17:01:54: Backup. Return value 3. MSI (s) (04:BC) 
[17:01:54:356]: User policy value 'DisableRollback' is 0 MSI (s) (04:BC) 
[17:01:54:356]: Machine policy value 'DisableRollback' is 0 MSI (s) (04:BC) 
[17:01:54:357]: Calling SRSetRestorePoint API. dwRestorePtType: 13, dwEventType: 103, llSequenceNumber: 342, szDescription: "". MSI (s) (04:BC) 
[17:01:54:357]: The call to SRSetRestorePoint API succeeded. Returned status: 0. MSI (s) (04:BC) 
[17:01:54:357]: Unlocking Server Action ended 17:01:54: INSTALL. Return value 3.