优化加载页面

Question

所以我正在处理WPF中的问题。

我有一个页面，当你点击RichTextBox作为输出数据框的按钮时加载。

问题是，它检查文件是否可以在FTP上访问，但它首先进行检查，所以需要一段时间，然后显示带有输出的页面。

我想首先显示页面与输出框，然后它将开始显示数据(就像你在安装程序等)。

这是页面本身的代码：

public partial class ArtaActionsPage : Page
{
    public ArtaActionsPage()
    {
        InitializeComponent();
        Loaded += OnLoaded;
    }

    private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
    {
        AddBlackLine("");
        AddBlackLine("Checking if everything is ready...");
        AddBlackLine("");

        bool AdobeReady = false;
        bool SevenZipReady = false;
        bool JavaReady = false;
        bool EsetReady = false;

        if (Global_Action_Variables.Arta_Variables.ArtaAdobeSwitch == true)
        {
            AddBlackLine("Checking for Adobe installator...");
            bool CheckForAdobe = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/Adobe_Reader.exe");
            if(CheckForAdobe == true)
            {
                AddGreenLine("Installer for Adobe accesible.");
                AdobeReady = true;
            }
            else
            {
                AddRedLine("Installer not accesible on FTP!!! Canceling job...");
                AddRedLine("Check FTP repozitary if file in Ultra_Script/Basic_SW/Adobe_Reader.exe exists and ftp account have enough rights for this file.");
            }
        }

        if (Global_Action_Variables.Arta_Variables.ArtaSevenZip == true)
        {
            AddBlackLine("");
            AddBlackLine("");
            AddBlackLine("Checking for SevenZip installer...");
            bool CheckForSevenZip = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/7zip.exe");
            if(CheckForSevenZip == true)
            {
                AddGreenLine("Installer for 7zip accesible.");
                SevenZipReady = true;
            }
            else
            {
                AddRedLine("Installer not accesible on FTP!!! Canceling job...");
                AddRedLine("Check FTP repozitary if file in Ultra_Script/Basic_SW/7zip.exe exists and ftp account have enough rights for this file.");
            }
        }

        if(Global_Action_Variables.Arta_Variables.ArtaJava == true)
        {
            AddBlackLine("");
            AddBlackLine("");
            AddBlackLine("Checking for Java installer...");
            bool CheckForJava = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/JaVa.exe");
            if(CheckForJava == true)
            {
                AddGreenLine("Installer for Java accesible");
                JavaReady = true;
            }
            else
            {
                AddRedLine("Installer not accesible on FTP!!! Canceling job...");
                AddRedLine("Check FTP repozitary if file in Ultra_Script/Basic_SW/JaVa.exe exists and ftp account have enough rights for this file.");
            }
        }

        if(Global_Action_Variables.Arta_Variables.ArtaEset == true)
        {
            AddBlackLine("");
            AddBlackLine("");
            AddBlackLine("Checking for Arta ESET installer...");
            bool CheckForArtaEset = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/Arta/ERA_ESET.exe");
            if(CheckForArtaEset == true)
            {
                AddGreenLine("Installer for ESET accesible");
                EsetReady = true;
            }
            else
            {
                AddRedLine("Installer not accesible on FTP!!! Canceling job...");
                AddRedLine("Check FTP repozitary if file in UUltra_Script/Basic_SW/Arta/ERA_ESET.exe exists and ftp account have enough rights for this file.");
            }
        }

        if(AdobeReady == true)
        {
            AddBlackLine("");
            AddBlackLine("");
            AddBlackLine("Test");
            General_Functions.DownloadFileFromFTP("Ultra_Script/Basic_SW/Adobe_Reader.exe", "Adobe_Reader.exe");
        }
        else
        {
            AddBlackLine("");
            AddRedLine("Failed.");
        }
    }

    private void AddRedLine(string text)
    {
        TextRange tr = new TextRange(outputBox.Document.ContentEnd, outputBox.Document.ContentEnd);
        tr.Text = text;
        tr.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Red);
        outputBox.AppendText("\r");
        outputBox.ScrollToEnd();
    }

    private void AddGreenLine(string text)
    {
        TextRange tr = new TextRange(outputBox.Document.ContentEnd, outputBox.Document.ContentEnd);
        tr.Text = text;
        tr.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Green);
        outputBox.ScrollToEnd();
    }

    private void AddBlackLine(string text)
    {
        TextRange tr = new TextRange(outputBox.Document.ContentEnd, outputBox.Document.ContentEnd);
        tr.Text = text;
        tr.ApplyPropertyValue(TextElement.ForegroundProperty, Brushes.Black);
        outputBox.AppendText("\r");
        outputBox.ScrollToEnd();
    }
}    

这是显示新页面的按钮的代码：

private void ArtaDoITButton_Click(object sender, RoutedEventArgs e)
{
    if (File.Exists("settings.xml"))
    {
        XmlSerializer xs = new XmlSerializer(typeof(Information));
        FileStream read = new FileStream("settings.xml", FileMode.Open, FileAccess.Read, FileShare.Read);
        Information info = (Information)xs.Deserialize(read);

        try
        {
            string a = info.FtpPassword;
            string FTPPassword = EncryDecryptor.Decrypt(a);
            bool TestFTP = General_Functions.isValidConnection(info.HDSynologyIP, info.FtpUsername, FTPPassword);
            if(TestFTP == true)
            {
                ArtaActionsFrame.Content = new ArtaActionsPage();
            }
            else
            {
                MessageBox.Show("Failed login to FTP repozitary. Check your credentials in settings.");
            }
        }
        catch(Exception ex)
        {
            MessageBox.Show(ex.ToString());
            read.Close();
        }
        read.Close();
    }
    else
    {
        MessageBox.Show("Chybí settings file!!");
    }
}     

页面的初始化：

public ArtaActionsPage()
{
    InitializeComponent();
    Loaded += OnLoaded;
}   

有谁知道如何优化它，这样它就不会在加载页面之前进行检查？

谢谢你所有的回答。

Answer 1

您必须使用async/await异步初始化Page。所有的初始化过程都应该移到一个公共InitalizeAsync()方法的ArtaActionsPage中：

加载页面事件处理程序：

private async void ArtaDoITButton_Click(object sender, RoutedEventArgs e)
{
  if (!File.Exists("settings.xml"))
  {
    MessageBox.Show("Chybí settings file!!");
    return;
  }

  var nextPage = new ArtaActionsPage();

  // Show the page immediately
  ArtaActionsFrame.Content = nextPage;

  if (!await nextPage.TryInitializeAsync())
  {
    MessageBox.Show("Failed login to FTP repozitary. Check your credentials in settings.");

    // Show previous page again
  }
}

Page.xaml.cs：

private void OnLoaded(object sender, RoutedEventArgs routedEventArgs)
{}

public async Task<bool> TryInitializeAsync()
{
  bool ftpIsValid = await ValidateFtpAsync();
  if (!ftpIsValid)
  {        
    return false;
  }

  await CheckIfFileExistsOnFTPAsync();
  return true;
}

private async Task<bool> ValidateFtpAsync()
{
  return await Task.Run(
    () =>
    {
      var xs = new XmlSerializer(typeof(Information));
      using (var read = new FileStream("settings.xml", FileMode.Open, FileAccess.Read, FileShare.Read))
      {
        Information info = (Information) xs.Deserialize(read);

        try
        {
          string a = info.FtpPassword;
          string fTPPassword = EncryDecryptor.Decrypt(a);
          return General_Functions.isValidConnection(info.HDSynologyIP, info.FtpUsername, FTPPassword);
        }
        catch (Exception ex)
        {
          MessageBox.Show(ex.ToString());
        }
      }

      return false;
    });
}

public async Task CheckIfFileExistsOnFTPAsync()
{
  bool ftpIsValid = await ValidateFtpAsync();
  if (!ftpIsValid)
  {        
    return false;
  }

  await Task.Run(
    () =>
    {
      AddBlackLine("");
      AddBlackLine("Checking if everything is ready...");
      AddBlackLine("");

      bool AdobeReady = false;
      bool SevenZipReady = false;
      bool JavaReady = false;
      bool EsetReady = false;

      if (Global_Action_Variables.Arta_Variables.ArtaAdobeSwitch == true)
      {
        AddBlackLine("Checking for Adobe installator...");
        bool CheckForAdobe = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/Adobe_Reader.exe");
        if (CheckForAdobe == true)
        {
          AddGreenLine("Installer for Adobe accesible.");
          AdobeReady = true;
        }
        else
        {
          AddRedLine("Installer not accesible on FTP!!! Canceling job...");
          AddRedLine(
            "Check FTP repozitary if file in Ultra_Script/Basic_SW/Adobe_Reader.exe exists and ftp account have enough rights for this file.");
        }
      }

      if (Global_Action_Variables.Arta_Variables.ArtaSevenZip == true)
      {
        AddBlackLine("");
        AddBlackLine("");
        AddBlackLine("Checking for SevenZip installer...");
        bool CheckForSevenZip = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/7zip.exe");
        if (CheckForSevenZip == true)
        {
          AddGreenLine("Installer for 7zip accesible.");
          SevenZipReady = true;
        }
        else
        {
          AddRedLine("Installer not accesible on FTP!!! Canceling job...");
          AddRedLine(
            "Check FTP repozitary if file in Ultra_Script/Basic_SW/7zip.exe exists and ftp account have enough rights for this file.");
        }
      }

      if (Global_Action_Variables.Arta_Variables.ArtaJava == true)
      {
        AddBlackLine("");
        AddBlackLine("");
        AddBlackLine("Checking for Java installer...");
        bool CheckForJava = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/JaVa.exe");
        if (CheckForJava == true)
        {
          AddGreenLine("Installer for Java accesible");
          JavaReady = true;
        }
        else
        {
          AddRedLine("Installer not accesible on FTP!!! Canceling job...");
          AddRedLine(
            "Check FTP repozitary if file in Ultra_Script/Basic_SW/JaVa.exe exists and ftp account have enough rights for this file.");
        }
      }

      if (Global_Action_Variables.Arta_Variables.ArtaEset == true)
      {
        AddBlackLine("");
        AddBlackLine("");
        AddBlackLine("Checking for Arta ESET installer...");
        bool CheckForArtaEset = General_Functions.CheckIfFileExistsOnFTP("Ultra_Script/Basic_SW/Arta/ERA_ESET.exe");
        if (CheckForArtaEset == true)
        {
          AddGreenLine("Installer for ESET accesible");
          EsetReady = true;
        }
        else
        {
          AddRedLine("Installer not accesible on FTP!!! Canceling job...");
          AddRedLine(
            "Check FTP repozitary if file in UUltra_Script/Basic_SW/Arta/ERA_ESET.exe exists and ftp account have enough rights for this file.");
        }
      }

      if (AdobeReady == true)
      {
        AddBlackLine("");
        AddBlackLine("");
        AddBlackLine("Test");
        General_Functions.DownloadFileFromFTP("Ultra_Script/Basic_SW/Adobe_Reader.exe", "Adobe_Reader.exe");
      }
      else
      {
        AddBlackLine("");
        AddRedLine("Failed.");
      }
    });
}

还要考虑将General_Functions.CheckIfFileExistsOnFTP()转换为async方法。

现在，ArtaActionsPage立即显示出来。无论初始化是否失败，InitializeAsync都会返回bool。如果失败了，您可以处理这种情况，例如，显示您的消息，然后导航回上一页。