为什么iprogress<t>report(t)方法阻塞了UI线程?

我在下面的代码中报告方法process2()中的进度时遇到问题。我想在每一行被读取之后增加进度条,但是这样做会阻塞UI,使其失去响应。如果我注释掉progress.report()行,它将不再阻塞UI线程。有人知道为什么会发生这种情况吗?我该如何解决?

下面是可以粘贴到Starter WPF应用程序中的完全工作的代码。

单击“运行”按钮(在开始生成文件时可能会有一个小的停顿,等待生成文件完成后),然后尝试移动窗口,它将保持冻结状态。

警告:此代码将在bin\debug文件夹(或您的配置指向的任何内容)中生成一个文本文件。如果从网络路径运行此文件,它可能无法写入此文件,因此建议从本地磁盘运行。

主窗口.xaml.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace WpfApplication2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        Queue<string> queue = new Queue<string>();

        List<string> stringsCollection = new List<string>() { "1_abc123_A_AA_zzz", "2_abc123_AAAA_zzz", "3_abc123_AAAAAA_zzz" };

        int linesCount = 0;
        int totalLines = 0;

        string ASSEMBLY_PATH;
        string file; 
        public MainWindow()
        {
            InitializeComponent();

            ASSEMBLY_PATH = ReturnThisAssemblyPath();
            file = ASSEMBLY_PATH + @"\test.txt";
            generateFile();
        }

        private async void Button_Click2(object sender, RoutedEventArgs e)
        {
            linesCount = 0;

            Progress<int> process2_progress;

            this.progress.Value = 0;
            this.status.Text = "";

            process2_progress = new Progress<int>();
            process2_progress.ProgressChanged += Process2_progress_ProgressChanged;

            this.status.Text += "Searching..." + Environment.NewLine;
            await Task.Run(() =>
            {
                totalLines = System.IO.File.ReadLines(file).Count();

                foreach (string s in stringsCollection)
                {
                    Application.Current.Dispatcher.Invoke(DispatcherPriority.Normal, (Action)(() =>
                    {
                        this.status.Text += "Searching " + s + Environment.NewLine;
                    }));
                    List<string> strCollection = Process2(s, process2_progress);

                    foreach (string str in strCollection)
                        queue.Enqueue(str);
                }
            });

            this.status.Text += "DONE!!" + Environment.NewLine;
        }

        private void Process2_progress_ProgressChanged(object sender, int e)
        {
            linesCount += e;
            this.progress.Value = linesCount * 100 / totalLines;
        }

        List<string> Process2(string inputString, IProgress<int> progress)
        {
            List<string> result = new List<string>();

            foreach (string line in System.IO.File.ReadLines(file, new UTF8Encoding()))
            {
                progress.Report(1);
            }

            return result;
        }

    void generateFile()
    {
        this.status.Text += "Generating FIle..." + Environment.NewLine;
        int count = 0;
        using (StreamWriter sw = new StreamWriter(file, true))
        {
            do
            {
                sw.WriteLine(Guid.NewGuid().ToString());
                count++;
            } while (count < 51000);

        }
        this.status.Text += "Done Generating FIle!" + Environment.NewLine;
    }

        public string ReturnThisAssemblyPath()
        {
            string codeBase = Assembly.GetAssembly(typeof(MainWindow)).CodeBase;
            UriBuilder uri = new UriBuilder(codeBase);
            string path = Uri.UnescapeDataString(uri.Path);
            return System.IO.Path.GetDirectoryName(path);
        }
    }
}

主窗口.xaml

<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApplication2"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto" />
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>

        <TextBox x:Name="status" Grid.Row="0"></TextBox>

        <Button Grid.Row="2" Height="50" Click="Button_Click2">Run2</Button>
        <ProgressBar x:Name="progress" Grid.Row="3" Height="20" ></ProgressBar>
    </Grid>
</Window>