A new class I created :

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace Extract
{
    class Satellite
    {
        private List<string> satelliteUrls = new List<string>();
        private string mainUrl = "https://some.com/";
        private string[] statements;

        public async Task DownloadSatelliteAsync()
        {
            using (var client = new WebClient())
            {
                client.Headers.Add("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.61 Safari/537.36");

                client.DownloadFileCompleted  = (s, e) =>
                {
                    if(e.Error == null)
                    {
                        ExtractLinks();
                    }
                };

                await client.DownloadFileTaskAsync(new Uri(mainUrl), @"d:\Downloaded Images\Satellite\extractfile"   ".txt");
            }
        }

        private void ExtractLinks()
        {
            var file = File.ReadAllText(@"d:\Downloaded Images\images\extractfile"   ".txt");

            int idx = file.IndexOf("arrayImageTimes.push");
            int idx1 = file.IndexOf("</script>", idx);

            string results = file.Substring(idx, idx1 - idx);
            statements = results.Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);

            for (int i = 0; i < statements.Length; i  )
            {
                if (i == 10)
                {
                    break;
                }

                string time = statements[i].Split('\'')[1];

                satelliteUrls.Add("https://some.com="   time);
            }
        }
    }
}

In Form1 top :

Satellite sat;

In the constructor in Form1 :

sat = new Satellite();

And a button click event :

private async void btnStart_Click(object sender, EventArgs e)
        {
            lblStatus.Text = "Downloading...";
            await sat.DownloadSatelliteAsync();
        }

It's downloading fine.

The problem is in the class Satellite I can't add a breakpoint on the break; line in the loop :

if (i == 10)
                    {
                        break;
                    }

I can put a breakpoint on the if and on the close } but not on the break

Second when it's ending extracting the links I can put a breakpoint at the bottom on the close } after the loop ending but then I can't see the List items. This is what I see :

There is 16 items but the size is 10 ?

The size should be 10 because the break; when i = 10 but why the List have 16 items ?

When I click on the items :

I deleted the links addresses but there are 10 items but then more 6 null items. Where this null's came from ? and why I can't add a breakpoint on the break; line ? why when I put the mous on the List I see this kind of rex x's and not the items ?

CodePudding user response：

_items is the internal array that stores the entities in your list. Its size corresponds to the list's .Capacity property.

_items doesn't expand 1:1 with adding items. It will typically double the available capacity when it runs out. Source code. The default capacity is 4 (according to the source), so it would double to 8, and then to 16, which is exactly what we see.

You can't pause execution on break; because i never reaches a value of 10.

As for the red Xs, the text next to it says:

Implicit function evaluation is turned off by the user

You can find the solution to that here. Essentially: go into Options, and under "Debugging" make sure "Enable property evaluation and other implicit function calls" is checked.