[C#.Net]判断文件是否被占用的两种方法

今天开发产线测试Tool时发现日志文件会几率性的被占用，上网浏览找到最简单的代码(API或者FileStream)，在这里抛砖引玉下。

第一种方法:API

using System.IO;  
using System.Runtime.InteropServices;  
 
[DllImport("kernel32.dll")]  
public static extern IntPtr _lopen(string lpPathName, int iReadWrite);  

[DllImport("kernel32.dll")]  
public static extern bool CloseHandle(IntPtr hObject);  
 
public const int OF_READWRITE = 2;  
public const int OF_SHARE_DENY_NONE = 0x40;  
public readonly IntPtr HFILE_ERROR = new IntPtr(-1);  
private void button1_Click(object sender, EventArgs e)  
{  
    string vFileName = @"c:\temp\temp.bmp";  
    if (!File.Exists(vFileName))  
    {  
        MessageBox.Show("文件都不存在!");  
        return;  
    }  
    IntPtr vHandle = _lopen(vFileName, OF_READWRITE | OF_SHARE_DENY_NONE);  
    if (vHandle == HFILE_ERROR)  
    {  
        MessageBox.Show("文件被占用！");  
        return;  
    }  
    CloseHandle(vHandle);  
    MessageBox.Show("没有被占用！");  
}  

第二种方法:FileStream

public static bool IsFileInUse(string fileName)  
 {  
        bool inUse = true;  
  
        FileStream fs = null;  
        try  
        {  
  
            fs = new FileStream(fileName, FileMode.Open, FileAccess.Read,  
  
            FileShare.None);  
  
            inUse = false;  
        }  
        catch  
        {   
        }  
        finally  
        {  
            if (fs != null)  
  
                fs.Close();  
        }  
        return inUse;//true表示正在使用,false没有使用  
}  

项目代码的部分(VB.Net)

 Sub Prepare()
        If File.Exists(logRW) Then File.Delete(logRW)
        Dim bflag As Boolean = False
        Try
            Do
                Shell("CMD.exe /C RW.exe /Command=LimitA.rw /LogFile=LimitA.log", AppWinStyle.Hide, True, 5000)
                Threading.Thread.Sleep(1000)
                While (IsFileInUse("LimitA.log"))
                    Threading.Thread.Sleep(2000)
                End While

                If File.Exists(logRW) Then
                    Dim All As String = My.Computer.FileSystem.ReadAllText(logRW)
                    '检查LogRW的0x01的位置的值是否为0x08
                    If All.Contains("Read EC Byte 0x01 = 0x80") Then
                        bflag = True
                    End If
                End If
            Loop Until bflag

            Using sr As New StreamReader(logRW)
                Do Until sr.EndOfStream
                    Dim s As String = sr.ReadLine
                    If s.Contains("Set Environment RwLOCAL3") Then
                        'Set Environment RwLOCAL3 = 4608 (DEC)
                        LimitA = CDbl(s.Split(New String() {"=", "("}, StringSplitOptions.RemoveEmptyEntries)(1))
                        Console.WriteLine("Limit Current: " & LimitA)
                        LogStr = LogStr & vbCrLf & "Limit Current: " & LimitA
                        Exit Do
                    End If
                Loop
            End Using

        Catch ex As Exception
            Console.WriteLine(ex.Message & Err.Description)
            Environment.Exit(1)
        End Try
    End Sub

    Function IsFileInUse(ByVal fileName As String)
        Dim inUse As Boolean = True
        Dim fs As FileStream = Nothing
        Try
            fs = New FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.None)
            inUse = False
        Catch ex As Exception

        Finally
            If (fs IsNot Nothing) Then
                fs.Close()
            End If
        End Try
        Return inUse
    End Function