CODEWITHSUNDEEP
c#task
Latheesan
Latheesan

Reputation: 24116

Passing parameters to Task.Factory.StartNew in .NET

I am working on a small utility that will scan a FTP folder that has a folder for each printer on our network. Within each printer folder, there will be files that needs printing.

So, here's the test code I have so far:

namespace PrintTest
{
    class Program
    {
        const string ftpDir = @"C:\Users\Latheesan\Desktop\FTP";

        static void Main(string[] args)
        {
            StartScan();

            Console.ReadKey();
        }

        static void StartScan()
        {
            // Scan ftp dir
            var printerDirs = Directory.GetDirectories(ftpDir);

            // Proceed if any printer dirs were found
            if (printerDirs.Length > 0)
            {
                // Init task list
                Task[] scanPrinterTasks = new Task[printerDirs.Length];

                // Iterate through each found printer dir
                for (int i = 0; i < printerDirs.Length; i++)
                {
                    // Configure printer tasks
                    var printerName = printerDirs[i];
                    printerDirs[i] = Task.Factory.StartNew(() => 
                        ScanPrinterDir(printerName));
                }

                // Wait for all tasks to finish
                Task.WaitAll(scanPrinterTasks);
            }
        }

        static void ScanPrinterDir(string printerName)
        {
            // todo
        }
    }
}

When I try to compile this, I get the following error:

Severity Code Description Project File Line Error CS0029 Cannot implicitly convert type 'System.Threading.Tasks.Task' to 'string' PrintTest C:\Users\Latheesan\Desktop\PrintTest\PrintTest\Program.cs 34

How do you pass parameters to a method invoked by Task.Factory.StartNew ?

Upvotes: 0

Views: 703

Answers (1)

Rohit
Rohit

Reputation: 10236

There is nothing wrong in passing parameters here however the return type of Task.Factory.StartNew is task not a string which is why you are getting compile time error.

I think you need 

       scanPrinterTasks[i] = Task.Factory.StartNew(() => 
                    ScanPrinterDir(printerName));

instead of 

      printerDirs[i] = Task.Factory.StartNew(() => 
                    ScanPrinterDir(printerName));

Upvotes: 4

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