C# using ThreadPool for multi-threaded application

I’m currently designing an application specifically to handle multiple processing at a certain time. I’ve read all articles about threading, whether to use a background worker, custom thread management, or by using a thread pool. What facinates me is the thread pool, just by passing a workitem viola you have a working multi-threaded application. See simple example below:


using System;
using System.Threading;

public class MyProcess
{

    private ManualResetEvent _doneEvent;

    public MyProcess(ManualResetEvent doneEvent)
    {
        _doneEvent = doneEvent;
    }

    public void MyProcessThreadPoolCallback(Object threadContext)
    {
        int threadIndex = (int)threadContext;
        Console.WriteLine("thread {0} started...", threadIndex);
        StartProcess();
        Console.WriteLine("thread {0} end...", threadIndex);

    // Indicates that the process had been completed
        _doneEvent.Set();
    }

    public void StartProcess()
    {
        // TODO: Add code for processing here

    }

  
}

public class ThreadPoolExample
{
    static void Main()
    {
        const int totalCountToProcess = 10;
        
        ManualResetEvent[] doneEvents = new ManualResetEvent[totalCountToProcess];
        MyProcess[] MyProcessArray = new MyProcess[totalCountToProcess];
      
        // Configure and launch threads using ThreadPool:
        Console.WriteLine("launching tasks...");
        for (int i = 0; i < totalCountToProcess ; i++)
        {
            doneEvents[i] = new ManualResetEvent(false);
            MyProcess p = new MyProcess(doneEvents[i]);
            MyProcess[i] = p;
            ThreadPool.QueueUserWorkItem(p.MyProcessThreadPoolCallback, i);
        }

        // Wait for all threads in pool to finished processing

        WaitHandle.WaitAll(doneEvents);
        Console.WriteLine("All Process are complete.");

           }
}

 

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Storing files to mssql database and downloading using Asp.NET

1) First create a new column and set it as varbinary(MAX) for the datatype.

2) Use this code to store the file to database:

            //Read File to Bytes
                    FileStream st = new FileStream(<Location of the file>, FileMode.Open);
                    byte[] fileData= new byte[st.Length];
                    st.Read(fileData, 0, (int)st.Length);
                    st.Close();

                    SqlParameter[] param = new SqlParameter[] { new SqlParameter(“@ID”,<Reference ID>),
                                                    new SqlParameter(“@Data”,fileData)  };

            int i = SqlAccessor.ExecuteNonQuery(<ConnectionString>, SqlAccessor.SqlCommandBuilder(new SqlCommand (<Stored Procedure Name>), param), CommandType.StoredProcedure, out retVal);

 I’ve used Application Blocks to simplify data operation.

To Retrieve the data and to be downloaded from an ASP.NET Page:

3)  I created a function that returns a byte array with ID as parameter

 public static byte[] GetFileFromDB(string id)
    {
        object[] retVal = null;
        byte[] file = null;
        SqlParameter[] param = new SqlParameter[]
        {
            new SqlParameter (“@id”, id)
        };
        string _connString = ConfigurationManager.ConnectionStrings[<ConnectionStringName>].ConnectionString.ToString();
        SqlDataReader reader = SqlAccessor.ExecuteReader(_connString, SqlAccessor.SqlCommandBuilder(new SqlCommand(“SourceFileLogSelFileDataProc”), param), CommandType.StoredProcedure, out retVal);

        if (reader.Read())
        {
            file = (byte[])reader[“<varbinary column that we define in Step 1>“];
        }

        return file;
    }

4) And on the ASP.NET Page itself, on the Page_Load event:

           byte[] fileData = Utils.GetFileFromDB(<ID>);
            Response.ClearContent();
            Response.AddHeader(“Content-Disposition”, “attachment; filename=” + <filename>);
            BinaryWriter bw = new BinaryWriter(Response.OutputStream);
            bw.Write(fileData);
            bw.Close();
            Response.ContentType = ReturnExtension(<file extension>);
            Response.End();

 5) I have another method to determine the ContentType:

  private string ReturnExtension(string fileExtension)
    {
        switch (fileExtension)
        {
            case “.htm”:
            case “.html”:
            case “.log”:
                return “text/HTML”;
            case “.txt”:
                return “text/plain”;
            case “.doc”:
                return “application/ms-word”;
            case “.tiff”:
            case “.tif”:
                return “image/tiff”;
            case “.asf”:
                return “video/x-ms-asf”;
            case “.avi”:
                return “video/avi”;
            case “.zip”:
                return “application/zip”;
            case “.xls”:
            case “.csv”:
                return “application/vnd.ms-excel”;
            case “.gif”:
                return “image/gif”;
            case “.jpg”:
            case “jpeg”:
                return “image/jpeg”;
            case “.bmp”:
                return “image/bmp”;
            case “.wav”:
                return “audio/wav”;
            case “.mp3”:
                return “audio/mpeg3”;
            case “.mpg”:
            case “mpeg”:
                return “video/mpeg”;
            case “.rtf”:
                return “application/rtf”;
            case “.asp”:
                return “text/asp”;
            case “.pdf”:
                return “application/pdf”;
            case “.fdf”:
                return “application/vnd.fdf”;
            case “.ppt”:
                return “application/mspowerpoint”;
            case “.dwg”:
                return “image/vnd.dwg”;
            case “.msg”:
                return “application/msoutlook”;
            case “.xml”:
            case “.sdxl”:
                return “application/xml”;
            case “.xdp”:
                return “application/vnd.adobe.xdp+xml”;
            default:
                return “application/octet-stream”;
        }
    }

Hope this helps.

System errorcode 53 while connecting to an existing network share drive

Recently I have encountered the famous error 53 (network path not found) while connecting to network share folder using C# WinAPI. So typically first step is to really check whether path is existing with valid credentials and yes it was there and the credential is valid. After one hour of checking an rechecking I discovered that the path (folder) was a DFS (Domain based File Share).

Resolution: Get the actual folder path from the referral list in DFS tab of the shared path

.