C#

class Program
{
    private static string _address;
    private static string _userName;
    private static string _password;
    static void Main(string[] args)
    {
    }
    // A FileSystemWatcher passes the file name into this method
    public static async void FileReceived(string fileName)
    {
        Task<string> t = await Task.Run(() => FTPFile(fileName));       // <=== ERROR HERE
        await t.ContinueWith((t1) =>
        {
            FileUploaded(t1.Result);
        });
    }
    // FTP the file to the server
    private static string FTPFile(string fileName)
    {
        string remoteFile = Path.GetFileName(fileName);
        SFTP sftp = new SFTP(_address, _userName, _password);
        sftp.UploadFileAsync(fileName, remoteFile);
        return fileName;
    }
    private static async void FileUploaded(string fileName)
    {
        // Once here, the file has been transfered.
    }
}

Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

/* This is a blink label user control --------------------------------*/
public partial class BlinkLabel : Label {

private CancellationTokenSource ts;
private Task task1;

public BlinkLabel()
{ 
   InitializeComponent(); 
}

public void StartBlink()
{
   ts=new CancellationTokenSource();
   CancellationToken ct = ts.Token;

   if ( isRunningTask(task1) ) return;

   task1 = Task.Factory.StartNew(() =>
   {
       while (true)
       {
           ct.ThrowIfCancellationRequested();
           Thread.Sleep(500);
           Visible = !Visible;
                    
       }
    }, ct);

    blinkTask.ContinueWith(t =>
    {
        Visible = false;

    },TaskContinuationOptions.None);

            
}

public void StopBlink()
{
    ts.Cancel();
}

}

/* This is a my main form that use blink label user control--------------------------------*/
public partial class MainForm: Form
{
    public MainForm
   {
       InitializeComponent(); 
      
       blinkLabel1.Text="Blinking message...";
       blinkLabel1.StartBlink(); //Works
       blinkLabel1.StopBlink();  //Not works - blink not stop.
   }
    
}

 try
{
    WebRequest request = WebRequest.Create("http://facebook.com");
    HttpWebResponse response = (HttpWebResponse) request.GetResponse();
    
    MessageBox.Show("I am here!");                
}
catch (Exception ex)
{
    MessageBox.Show("Error Occurred!");
}