C＃<不能應用於'long'和'string'類型的操作數

Question

我試圖找到解決此錯誤的解決方法，因爲我正在比較從主機到本地系統上的文件大小，但我試試這個：

if (CheckFileBytes < FileBytes)它提供了以下錯誤

Operator '<' cannot be applied to operands of type 'long' and 'string'

下面是一些代碼：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) 
    { 
     if (File.Exists(Application.StartupPath + "\\checkfiles.lst")) 
     { 
      string path = Application.StartupPath + "\\checkfiles.lst"; 

      // Open the file to read from. 
      foreach (string readText in File.ReadLines(path)) 
      { 
       var elements = readText.Split('|'); 
       ElementsFile = elements[0]; 
       MD5Hash = elements[1]; 
       FileBytes = elements[2]; 
       //Console.WriteLine(ElementsFile + MD5Hash + FileBytes); 
       string fileName = Application.StartupPath + "\\" + ElementsFile; 
       byte[] buffer; 
       int bytesRead; 
       long size; 
       long totalBytesRead = 0; 

       using (Stream file = File.OpenRead(fileName)) 
       { 
        size = file.Length; 
        //var fileName = Application.StartupPath + "\\" + ElementsFile; 
        FileInfo fi = new FileInfo(fileName); 
        var Filebytes = fi.Length; 
        using (HashAlgorithm hasher = MD5.Create()) 
        { 
         do 
         { 
          buffer = new byte[4096]; 

          bytesRead = file.Read(buffer, 0, buffer.Length); 

          totalBytesRead += bytesRead; 

          hasher.TransformBlock(buffer, 0, bytesRead, null, 0); 

         } 
         while (bytesRead != 0); 

         hasher.TransformFinalBlock(buffer, 0, 0); 

         HashString = MakeHashString(hasher.Hash); 
        } 
        //Return Local file size 
        long CheckFileBytes = Filebytes; 
        //Return local MD5 hash string 
        string CheckFileHash = HashString; 
        //Return local file path 
        if (CheckFileHash != MD5Hash && CheckFileBytes < FileBytes) 
        { 
        ... 
} 
} 

後續ING是在課程開始時宣佈：

string ElementsFile = null; 
string MD5Hash = null; 
string FileBytes = null; 
string HashString = null; 

Answer 1

聲明FileBytes作爲一項長期的，而不是：

long FileBytes = 0; 

然後從文件轉換你的價值很長，當你給它分配：

FileBytes = long.Parse(elements[2]); 

與之相比，CheckFileBytes應該可以正常工作。

---

如果有一個機會，elements[2]可能不是一個有效的數字，可以考慮使用long.TryParse()代替。

long.TryParse(elements[2], out FileBytes);