问c# Winforms - CLR20r3异常

EN

Problem Event Name: CLR20r3
  Problem Signature 01: ExDraw.exe
  Problem Signature 02: 1.0.2.3
  Problem Signature 03: 59be5ce4
  Problem Signature 04: mscorlib
  Problem Signature 05: 4.6.1590.0
  Problem Signature 06: 5787ed44
  Problem Signature 07: f9d
  Problem Signature 08: 96
  Problem Signature 09: System.FormatException
  OS Version:   6.1.7601.2.1.0.256.1
  Locale ID:    1033
  Additional Information 1: 0a9e
  Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
  Additional Information 3: 0a9e
  Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

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private void DownloadAddonsListCompleted(object sender, DownloadStringCompletedEventArgs e)
    {
        var result = StringHelper.DecryptMyString(e.Result);
        foreach (var line in result.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries))
        {
            var statusAddons = File.Exists("Addons\\" + line.Split('~')[0] + ".addon")
                ? "Installed"
                : "-";

            var localAddonsVersion = "-";
            if (statusAddons != "-")
            {
                localAddonsVersion = File.ReadAllText("Addons\\" + line.Split('~')[0] + ".version");
                if (Convert.ToDouble(localAddonsVersion) < Convert.ToDouble(line.Split('~')[1]))
                    statusAddons = "Outdated";
            }

            var _WebClient = new WebClient();
            var fileName = line.Split('~')[0].Replace(" ", string.Empty) + ".html";
            _WebClient.DownloadFileTaskAsync(line.Split('~')[3],
                RequiredPath.ADDONSDESCRIPTIONPATH + "\\" + fileName).Wait();

            rgvList.Invoke(new Action(() =>
                rgvList.Rows.Add
                (
                    line.Split('~')[0],
                    statusAddons,
                    localAddonsVersion,
                    line.Split('~')[1],
                    line.Split('~')[2],
                    line.Split('~')[3],
                    line.Split('~')[4],
                    RequiredPath.ADDONSDESCRIPTIONPATH + "\\" + fileName
                )));

        }
    }