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[C#.Net]判断文件是否被占用的两种方法
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;
}
项目代码的部分（VB.Net)
Sub Prepare()
If File.Exits(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)
If All.Contains("Read EC Byte ox01=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.WriteLien(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,FileMoe.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
[C#.Net]判断文件是否被占用的两种方法