在後臺工作人員查詢中打開一個目錄並處理文件/文件夾

Question

我有以下代碼，我試圖打開一個目錄並通過後臺工作人員處理其中的文件，但我遇到了問題。

我遇到的錯誤是（名稱filePath在當前上下文中不存在），我可以理解它，因爲它存儲在另一個方法中？如果有人可以指出我的代碼有什麼問題，我將不勝感激。 Folderbrowser不能在後臺工作器部分下工作。

private void btnFiles_Click(object sender, EventArgs e) 
    { 
     //btnFiles.Enabled = false; 
     btnSTOP.Enabled = true; 
     //Clear text fields 
     listBoxResults.Items.Clear(); 
     listBoxPath.Items.Clear(); 
     txtItemsFound.Text = String.Empty; 
     //Open folder browser for user to select the folder to scan 
     DialogResult result = folderBrowserDialog1.ShowDialog(); 
     if (result == DialogResult.OK) 
     { 
      //Store selected folder path 
      string filePath = folderBrowserDialog1.SelectedPath; 
     } 
     //Start the async operation here 
     backgroundWorker1.RunWorkerAsync(); 
    } 

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
    { 
     //Process the folder 
      try 
      { 
       foreach (string dir in Alphaleonis.Win32.Filesystem.Directory.EnumerateFiles(filePath, "*.*", SearchOption.AllDirectories, true)) 
       { 
        //Populate List Box with all files found 
        this.Invoke(new Action(() => listUpdate2(dir))); 
        FileInfo fi = new FileInfo(dir); 
        if (fi.Length == 0) 
        { 
         //Populate List Box with all empty files found 
         this.Invoke(new Action(() => listUpdate1(dir + Environment.NewLine))); 
        } 
       } 
      } 

      //Catch exceptions 
      catch (Exception err) 
      { 
       // This code just writes out the message and continues to recurse. 
       log.Add(err.Message); 
       //throw; 
      } 
      finally 
      { 
       //add a count of the empty files here 
       txtItemsFound.Text = listBoxResults.Items.Count.ToString(); 

       // Write out all the files that could not be processed. 
       foreach (string s in log) 
       { 
        this.Invoke(new Action(() => listUpdate1(s))); 
       } 
       log.Clear(); 
       MessageBox.Show("Scanning Complete", "Done", MessageBoxButtons.OK, MessageBoxIcon.Exclamation); 
      } 
      //If cancel button was pressed while the execution is in progress 
      //Change the state from cancellation ---> cancelled 
      if (backgroundWorker1.CancellationPending) 
      { 
       e.Cancel = true; 
       //backgroundWorker1.ReportProgress(0); 
       return; 
      } 
      //} 
      //Report 100% completion on operation completed 
      backgroundWorker1.ReportProgress(100); 
     } 

Answer 1

將變量「filePath」聲明爲btnFiles_Click方法的本地變量。爲了讓它在別處使用，它必須聲明爲全局的代碼頁：

public class Form1 
{ 
    private String _filePath = null; 

    private void btnFiles_Click(object sender, EventArgs e) 
    { 
     //get your file and assign _filePath here... 
     _filePath = folderBrowserDialog1.SelectedPath; 
    } 

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
    { 
     //use _filePath here... 
    } 
} 

Answer 2

@DonBoitnott解決方案是最常見的用於內部類的數據流。具體到BackgroundWorker還有另一個存在

private void btnFiles_Click(object sender, EventArgs e) 
{ 
    ... 
    // pass folder name 
    backgroundWorker1.RunWorkerAsync(folderBrowserDialog1.SelectedPath); 
} 

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
{ 
    // get passed folder name 
    string filePath = (string)e.Argument; 
    ... 
}