使用 Parallel.ForEach 执行多个帖子

Question

这是我的语法，但我的行上一直有一个编译错误 Parallel.ForEach()

System.Data.DataRow is a type but is used like a variable

我确信这很简单，我只是忽略了。以下是我的完整语法，如果有人能帮助我解决我所缺少的，我将不胜感激！

private void TryParallel()
{
  Dictionary<string, string> dic = new Dictionary<string, string>();
  string strEndpointURL = string.Format("http://sitetosenddatato.com/post");
  SqlDataReader reader;
  string strPostData = "";
  string strMessage = "";
  DataSet grds = new DataSet();
  grds = GetSQLResults();
  if (grds.Tables[0].Rows.Count >= 1)
  {
    Parallel.ForEach(DataRow, grds.Tables[0].Rows =>
    {
        dic.Add("userID", reader.GetValue(0).ToString());
        dic.Add("name", reader.GetValue(1).ToString());
        dic.Add("address", reader.GetValue(2).ToString());
        dic.Add("city", reader.GetValue(3).ToString());
        dic.Add("state", reader.GetValue(4).ToString());
        dic.Add("zip", reader.GetValue(5).ToString());
        dic.Add("Phone", reader.GetValue(6).ToString());
    });
  }
  System.Web.Script.Serialization.JavaScriptSerializer json = new System.Web.Script.Serialization.JavaScriptSerializer();
  foreach (var d in dic) { strPostData += d.Key + "=" + Server.UrlEncode(d.Value) + "&"; }
  strPostData += "hs_context=";
S  ystem.Net.HttpWebRequest r = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(strEndpointURL);
  r.Method = "POST";
  r.Accept = "application/json";
  r.ContentType = "application/x-www-form-urlencoded";
  r.ContentLength = strPostData.Length;
  r.KeepAlive = false;
  using (System.IO.StreamWriter sw = new System.IO.StreamWriter(r.GetRequestStream()))
  {
    try { sw.Write(strPostData); }
    catch (Exception ex) { strMessage = ex.Message; }
  }
  var response = r.GetResponse();
  Stream receiveStream = response.GetResponseStream();
  StreamReader readStream = new StreamReader(receiveStream, Encoding.UTF8);
  var result = readStream.ReadToEnd();
  var xml = System.Xml.Linq.XElement.Parse(result);
  if (xml.Elements("success").FirstOrDefault().Value == "1") { strMessage = "Success"; }
  else
  {
    var errors = xml.Elements("errors");
    foreach (var error in errors.Elements("error")) { strMessage = error.Value; }
  }
}

编辑
按照@Glen Thomas 下面概述的示例 - 我将代码更改为

if (grds.Tables[0].Rows.Count == 1)
{
  Parallel.ForEach(rows, row =>
  {
    dic.Add("userID", reader.GetValue(0).ToString());
    //More Here
  }
}

出现编译错误：

Use of unassigned local variable 'reader'

但是我在方法的顶部声明了 reader？

Answer 1

您正在指定一个类型名称作为第一个参数。这应该是您正在迭代的集合。第二个参数是要执行的函数，集合中的每个元素都有一个参数。

Parallel.ForEach的正确用法是这样的：

var rows = new DataRow[0]

Parallel.ForEach(rows, row =>
{
    // Do something with row here
});

对于您的代码：

Parallel.ForEach(grds.Tables[0].Rows.OfType<DataRow>(), row =>
{
    dic.Add("userID", reader.GetValue(0).ToString());
    dic.Add("name", reader.GetValue(1).ToString());
    dic.Add("address", reader.GetValue(2).ToString());
    dic.Add("city", reader.GetValue(3).ToString());
    dic.Add("state", reader.GetValue(4).ToString());
    dic.Add("zip", reader.GetValue(5).ToString());
    dic.Add("Phone", reader.GetValue(6).ToString());
});

Answer 2

我相信你想这样做：

    Parallel.ForEach(grds.Tables[0].Rows.OfType<DataRow>(), (row) =>
    {
        dic.Add("userID", reader.GetValue(0).ToString());
        dic.Add("name", reader.GetValue(1).ToString());
        dic.Add("address", reader.GetValue(2).ToString());
        dic.Add("city", reader.GetValue(3).ToString());
        dic.Add("state", reader.GetValue(4).ToString());
        dic.Add("zip", reader.GetValue(5).ToString());
        dic.Add("Phone", reader.GetValue(6).ToString());

        //though realistically you should be doing something with your specific row
    });

答案在您收到的错误消息中 - DataRow 未在您提供的代码中定义为对象。

然而，这甚至没有真正解决您的实际问题，我认为这是并行执行多个 HTTP posts - 所以您需要将您的 post 逻辑放在匿名中你的 Parallel.ForEach()

的功能

使用 Parallel.ForEach 执行多个帖子

Perform Multiple Posts WIth Parallel.ForEach

c#

asp.net

parallel.foreach