Question

我有以下代码，我想使用c＃4.0转换为多线程。有可能吗？非常感谢任何指导。

我有一个按钮开始启动过程，它调用以下函数

private void ProcessData()
{
    //clear some ui text fields and disable start button and enable cancel button and set status to working
    //open database connection
    try
    {
        //populate ui multi line textbox saying that it is getting data from database
        var dsResult = new DataSet();
        //populate dataset
        //populate ui multi line textbox saying that it finished getting data from database
        //close connection

        if (dsResult.Tables.Count == 1 && dsResult.Tables[0].Rows.Count > 0)
        {
            //populate another field saying how much records we got
            int iCount = 1;
            foreach (DataRow dr in dsResult.Tables[0].Rows)
            {
                if (_stop)
                {
                    //set the status as forced stop
                    return;
                }
                //populate the currently processed record count using iCount
                //populate ui multi line textbox indicating which item that it is starting to work using dr["Item"]
                //call some external function to process some data, inside this function i have to update ui multi line textbox as well
                var dataFile = SearchDataFile(dr["Item"].ToString());
                if (dataFile == null)
                {
                    //populate ui multi line textbox indicating that item was not found
                    iCount++;
                    continue;
                }
                //call another external function to process some data, inside this function i have to update ui multi line textbox as well
                UpdateDataFile(dataFile, folderId, dr, dr["Item"].ToString());
                iCount++;
            }
        }
        else
        {
            //populate ui multi line textbox indicating no data found
        }
        //update status saying that it is complete
        tsslblStatus.Text = "STATUS : COMPLETE";
    }
    catch (Exception ex)
    {
        //close connection
        //populate ui multi line textbox indicating error occured
        //update status to error
    }
    finally
    {
        //re adjust ui and enabling start and disable stop
        //set _stop variable to false
    }
}

由于

Answer 1

首先拆分你的逻辑

SomeJobA();
SomeJobB();
SomeJobC();
...

然后做一些多线程

start SomeJobA() thread/task
start SomeJobB() thread/task
start SomeJobC() thread/task
...
to wait or not to wait for them to finish?

要使用其他帖子更新用户Invoke / BeginInvoke。

Answer 2

我发现最简单的方法是使用Parallel.ForEach方法，而不是

foreach (DataRow dr in dsResult.Tables[0].Rows)

使用

 Parellel.Foreach(dsResult.Tables[0].Rows, dr =>
 {
   //foreach body code goes here.
 });

但是，如果您尝试更新操纵UI的算法以利用并发性，那么您将遇到不好的时间。 Win form应用程序（如果我没记错，Win 8 /手机应用程序）不允许您从主线程以外的任何线程操作UI（即写入文本框）。

为了正确并行化此算法，您需要分离出操作UI的所有代码。

您可以使用TaskFactory整理您想要并行完成的工作：

public class MyState{
   public string Example {get;set;}
}

private MyState _state;

private void MethodCalledFromUIThread()
{
    //Update UI.
    TextBox1.Text = string.Empty;

    //Start parallel work in a new thread.
    new TaskFactory().StartNew(() => ThreadedMethod())
        //Wait for background threads to complete
        .Wait();

     //Update UI with result of processing.
     TextBox1.Text = _state.Example;
}

private void ThreadedMethod()
{
     //load dsResult

     Parallel.ForEach(dsResult.Tables[0].Rows, dr =>
     {
         //process data in parallel.
     }

     //Update the State object so the UI thread can get access to the data

     _state = new MyState{Example = "Data Updated!";}
}

将单线程c＃代码转换为多线程

2 个答案: