[英]Cancel Async Task with CancellationTokenSource from a button click not working
[英]Cancel Async Task from a button
我需要做的是能够取消运行异步的任务。
我一直在寻找,似乎无法绕过它。 我似乎无法辨别它将如何实现到我当前的设置中。
这是我的代码,它解雇了我的任务。 任何有关在何处或如何实施取消令牌的帮助将不胜感激。
private async void startThread()
{
//do ui stuff before starting
ProgressLabel.Text = String.Format("0 / {0} Runs Completed", index.Count());
ProgressBar.Maximum = index.Count();
await ExecuteProcesses();
//sort list of output lines
outputList = outputList.OrderBy(o => o.RunNumber).ToList();
foreach (Output o in outputList)
{
string outStr = o.RunNumber + "," + o.Index;
foreach (double oV in o.Values)
{
outStr += String.Format(",{0}", oV);
}
outputStrings.Add(outStr);
}
string[] csvOut = outputStrings.ToArray();
File.WriteAllLines(settings.OutputFile, csvOut);
//do ui stuff after completing.
ProgressLabel.Text = index.Count() + " runs completed. Output written to file test.csv";
}
private async Task ExecuteProcesses()
{
await Task.Factory.StartNew(() =>
{
int myCount = 0;
int maxRuns = index.Count();
List<string> myStrings = index;
Parallel.ForEach(myStrings,
new ParallelOptions()
{
MaxDegreeOfParallelism = settings.ConcurrentRuns
}, (s) =>
{
//This line gives us our run count.
int myIndex = myStrings.IndexOf(s) + 1;
string newInputFile = Path.Combine(settings.ProjectPath + "files/", Path.GetFileNameWithoutExtension(settings.InputFile) + "." + s + ".inp");
string newRptFile = Path.Combine(settings.ProjectPath + "files/", Path.GetFileNameWithoutExtension(settings.InputFile) + "." + s + ".rpt");
try
{
//load in contents of input file
string[] allLines = File.ReadAllLines(Path.Combine(settings.ProjectPath, settings.InputFile));
string[] indexSplit = s.Split('.');
//change parameters here
int count = 0;
foreach (OptiFile oF in Files)
{
int i = Int32.Parse(indexSplit[count]);
foreach (OptiParam oP in oF.Parameters)
{
string line = allLines[oP.LineNum - 1];
if (oP.DecimalPts == 0)
{
string sExpression = oP.Value;
sExpression = sExpression.Replace("%i", i.ToString());
EqCompiler oCompiler = new EqCompiler(sExpression, true);
oCompiler.Compile();
int iValue = (int)oCompiler.Calculate();
allLines[oP.LineNum - 1] = line.Substring(0, oP.ColumnNum - 1) + iValue.ToString() + line.Substring(oP.ColumnNum + oP.Length);
}
else
{
string sExpression = oP.Value;
sExpression = sExpression.Replace("%i", i.ToString());
EqCompiler oCompiler = new EqCompiler(sExpression, true);
oCompiler.Compile();
double dValue = oCompiler.Calculate();
dValue = Math.Round(dValue, oP.DecimalPts);
allLines[oP.LineNum - 1] = line.Substring(0, oP.ColumnNum - 1) + dValue.ToString() + line.Substring(oP.ColumnNum + oP.Length);
}
}
count++;
}
//write new input file here
File.WriteAllLines(newInputFile, allLines);
}
catch (IOException ex)
{
MessageBox.Show(ex.ToString());
}
var process = new Process();
process.StartInfo = new ProcessStartInfo("swmm5.exe", newInputFile + " " + newRptFile);
process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
process.Start();
process.WaitForExit();
Output output = new Output();
output.RunNumber = myIndex;
output.Index = s;
output.Values = new List<double>();
foreach(OutputValue oV in OutputValues) {
output.Values.Add(oV.getValue(newRptFile));
}
outputList.Add(output);
//get rid of files after run
File.Delete(newInputFile);
File.Delete(newRptFile);
myCount++;
ProgressBar.BeginInvoke(
new Action(() =>
{
ProgressBar.Value = myCount;
}
));
ProgressLabel.BeginInvoke(
new Action(() =>
{
ProgressLabel.Text = String.Format("{0} / {1} Runs Completed", myCount, maxRuns);
}
));
});
});
}
支持取消的最佳方法是将CancellationToken
传递给async
方法。 然后可以按下按钮以取消令牌
class TheClass
{
CancellationTokenSource m_source;
void StartThread() {
m_source = new CancellationTokenSource;
StartThread(m_source.Token);
}
private async void StartThread(CancellationToken token) {
...
}
private void OnCancelClicked(object sender, EventArgs e) {
m_source.Cancel();
}
}
但这还不够。 一旦CancellationToken
注册为取消,则需要更新startThread
和StartProcess
方法以协同取消任务
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.