LINQ在foreach停止响应 [英] LINQ stops responding at foreach
问题描述
我是一名本科生软件工程专业的学生，我建立了一个程序，该程序可以在美国地图上生成热图，这是我研究的一部分.它从SQL数据库或边缘列表文件中读取基于邮政编码的器官移植数据，并使用SQL数据库中的另一个表将邮政编码转换为长/纬度坐标.我创建了一个盈余/赤字模式，用于计算每个拉链的相对器官数(捐赠的器官减去接收的器官).此功能与基于SQL的数据完美配合.但是，边缘列表的新代码使程序在随后的foreach评估中停止响应.请查看下面的代码，并提出任何问题.请注意，这也是我的第一个大型LINQ项目. =)谢谢！
这是基于SQL的数据的代码，可以顺利运行.
I''m an undergrad Software Engineering student and I have built a program that generates heat maps on top of a map of the US as part of my research. It reads zipcode-based organ transplant data from a SQL database or edge list file and uses another table in the SQL database to transform the zips to long/lat coordinates. I''ve created a surplus/deficit mode that calculates the relative number of organs per zip (donated organs minus received organs). This functionality worked perfectly with SQL-based data. However, the new code for edge lists causes the program to stop responding at a following foreach evaluation. Please see the code below and ask any questions you have. Kindly note that this is my first big LINQ project too. =) Thanks!
This is the code for the SQL-based data that works without a hitch.
private IQueryable<HeatSource> getHeatDataGeneric(IQueryable<ZipCodes> zips, string organ, HeatField field)
{
IQueryable<AllTrans> organSet = biocomplex.AllTrans.Where(t => t.complete && t.organ == organ);
switch (field)
{
/* irrelevant code removed */
case HeatField.Surplus:
var donated = from z in zips
join t in organSet.GroupBy(t => t.donor_zip) on z.zip equals t.Key
select new { zip = z.zip, longitude = z.longitude, latitude = z.latitude, value = t.Count() };
var received = from z in zips
join t in organSet.GroupBy(t => t.recip_zip) on z.zip equals t.Key
select new { zip = z.zip, longitude = z.longitude, latitude = z.latitude, value = t.Count() };
return donated.Join(received, d => d.zip, r => r.zip, (d, r) => new HeatSource() { longitude = d.longitude, latitude = d.latitude, value = d.value - r.value });
/* irrelevant code removed */
}
}
这是边缘列表的非常相似的代码，后来冻结在foreach处.构建列表之前的位，并在需要时包含以供参考.
This is the very similar code for edge lists that later freezes at the foreach. The bit before it builds the List and is included for reference, if necessary.
class Edge
{
public string start;
public string end;
public void pad()
{
start = start.PadLeft(5, ''0'');
end = end.PadLeft(5, ''0'');
}
}
List<Edge> datalist;
private IQueryable<HeatSource> getHeatData(IQueryable<ZipCodes> zips)
{
// Population
if (populationToolStripMenuItem.Checked)
/* irrelevant code removed */
// Edge list
else if (edgeListDonorsToolStripMenuItem.Checked || edgeListRecipientsToolStripMenuItem.Checked || edgeListSurplusDeficitToolStripMenuItem.Checked)
{
if (sourceClicked)
{
datalist = new List<Edge>();
dlgOpenEdgeList.ShowDialog();
string file = dlgOpenEdgeList.FileName;
if (file == "")
return null;
this.Text += ": " + file;
StreamReader sr = new StreamReader(file);
while (sr.Peek() >= 0)
{
string[] line = sr.ReadLine().Split('','');
Edge e = new Edge();
e.start = line[0];
e.end = line[1];
e.pad();
datalist.Add(e);
}
sourceClicked = false;
}
/* dataq contains the expected data (checked using a break) */
IQueryable<Edge> dataq = datalist.AsQueryable();
if (edgeListSurplusDeficitToolStripMenuItem.Checked)
{
/* the Results View of donated and received can''t be viewed when debugging at a breakpoint; the evaluation "times out" */
var donated = from z in zips
join t in dataq.GroupBy(t => t.start) on z.zip equals t.Key
select new { zip = z.zip, longitude = z.longitude, latitude = z.latitude, value = t.Count() };
var received = from z in zips
join t in dataq.GroupBy(t => t.end) on z.zip equals t.Key
select new { zip = z.zip, longitude = z.longitude, latitude = z.latitude, value = t.Count() };
return donated.Join(received, d => d.zip, r => r.zip, (d, r) => new HeatSource() { longitude = d.longitude, latitude = d.latitude, value = d.value - r.value });
}
这段代码是我遇到问题的地方.我正在使用StreamWriter进行一些老式的调试.
This code is where I experience the problem. I was using the StreamWriter to do some old-school debugging.
var heatData = getHeatData(zips);
updateStatus("Grouping raw heat data...");
var heatQ = heatData.AsEnumerable().Select<HeatSource, HeatPoint>(h => new HeatPoint(longLatToPoint(h.longitude, h.latitude), h.value));
heatQ = from h in heatQ
group h by h.point into points
select new HeatPoint(points.Key, points.Sum(p => p.value));
updateStatus("Applying heat radius...");
StreamWriter sw = new StreamWriter(@"C:\Users\Evan Stoner\Documents\!debug.txt", false);
sw.AutoFlush = true;
/* irrelevant code removed */
/* heatQ.Count() will also freeze the program */
//int heatQ_Count = heatQ.Count();
sw.WriteLine("skip heatQ_Count");
sw.WriteLine("starting foreach block");
/* the program stops responding here, and nothing inside the foreach executes */
foreach (var h in heatQ)
{
for (int i = -heatRadius; i <= heatRadius; i++)
{
for (int j = -heatRadius; j <= heatRadius; j++)
{
if (h.point.X + i >= 0 && h.point.X + i < heat.GetLength(0) && h.point.Y + j >= 0 && h.point.Y + j < heat.GetLength(1))
{
sw.Write("pt: " + h.point.X + "\t" + h.point.Y + "\tat: " + i + ",\t" + j);
int diffusedHeat = heatRadius == 0 ? h.value : (int)(h.value - (h.value * Math.Sqrt(Math.Pow(i, 2) + Math.Pow(j, 2)) / heatDistance));
sw.Write("\tdiffused");
heat[h.point.X + i, h.point.Y + j] += diffusedHeat
sw.WriteLine(", set");
}
}
}
}
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