将单线程c#代码转换为多线程代码

本文关键字：代码 多线程 转换 单线程 | 更新日期: 2023-09-27 18:06:57

我有下面的代码，我想转换为多线程使用c# 4.0。这可能吗?如有任何指导，不胜感激。

我有一个按钮开始启动进程，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
    }
}

谢谢

将单线程c#代码转换为多线程代码

先拆分逻辑

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?

从其他线程使用Invoke/BeginInvoke更新UI

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.
 });

然而，如果你试图更新一个操纵UI以利用并发性的算法，你将会有一个糟糕的时间。Win表单应用程序(如果我没记错的话，Win 8/phone应用程序)不允许从主线程以外的任何线程操作UI(即写入文本框)。

为了正确地并行化这个算法，你需要分离出所有操作UI的代码。

您可以使用TaskFactory编组出您想并行执行的工作:

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!";}
}
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