在.net中，怎么知道一个文件正在被写入？

Question

thank you

Answer 1

我做得有个例子..当初我监视安装程序的.呵呵..
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;namespace Example120_响应文件系统事件
{
/// <summary>
/// Form1 的摘要说明。
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
private System.IO.FileSystemWatcher fileSystemWatcher1;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.FolderBrowserDialog folderBrowserDialog1;
private System.Windows.Forms.TextBox txtpath;
private System.Windows.Forms.TextBox txt1;
/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.Container components = null; public Form1()
{
//
// Windows 窗体设计器支持所必需的
//
InitializeComponent(); //
// TODO: 在 InitializeComponent 调用后添加任何构造函数代码
//
} /// <summary>
/// 清理所有正在使用的资源。
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null) 
{
components.Dispose();
}
}
base.Dispose( disposing );
} #region Windows Form Designer generated code
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.fileSystemWatcher1 = new System.IO.FileSystemWatcher();
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.folderBrowserDialog1 = new System.Windows.Forms.FolderBrowserDialog();
this.txtpath = new System.Windows.Forms.TextBox();
this.txt1 = new System.Windows.Forms.TextBox();
((System.ComponentModel.ISupportInitialize)(this.fileSystemWatcher1)).BeginInit();
this.SuspendLayout();
// 
// fileSystemWatcher1
// 
this.fileSystemWatcher1.EnableRaisingEvents = true;
this.fileSystemWatcher1.IncludeSubdirectories = true;
this.fileSystemWatcher1.NotifyFilter = ((System.IO.NotifyFilters)((System.IO.NotifyFilters.FileName | System.IO.NotifyFilters.DirectoryName)));
this.fileSystemWatcher1.Path = "c:\\";
this.fileSystemWatcher1.SynchronizingObject = this;
this.fileSystemWatcher1.Deleted += new System.IO.FileSystemEventHandler(this.fileSystemWatcher1_Deleted);
this.fileSystemWatcher1.Renamed += new System.IO.RenamedEventHandler(this.fileSystemWatcher1_Renamed);
this.fileSystemWatcher1.Created += new System.IO.FileSystemEventHandler(this.fileSystemWatcher1_Created);
// 
// button1
// 
this.button1.Location = new System.Drawing.Point(392, 8);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(64, 24);
this.button1.TabIndex = 4;
this.button1.Text = "清除";
this.button1.Click += new System.EventHandler(this.button1_Click);
// 
// button2
// 
this.button2.Location = new System.Drawing.Point(304, 8);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(64, 24);
this.button2.TabIndex = 5;
this.button2.Text = "监视目录";
this.button2.Click += new System.EventHandler(this.button2_Click);
// 
// folderBrowserDialog1
// 
this.folderBrowserDialog1.Description = "请选择要监视的目录";
this.folderBrowserDialog1.SelectedPath = "C:\\";
this.folderBrowserDialog1.ShowNewFolderButton = false;
// 
// txtpath
// 
this.txtpath.Location = new System.Drawing.Point(8, 8);
this.txtpath.Name = "txtpath";
this.txtpath.ReadOnly = true;
this.txtpath.Size = new System.Drawing.Size(288, 21);
this.txtpath.TabIndex = 7;
this.txtpath.Text = "c:\\";
// 
// txt1
// 
this.txt1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
| System.Windows.Forms.AnchorStyles.Left) 
| System.Windows.Forms.AnchorStyles.Right)));
this.txt1.Location = new System.Drawing.Point(0, 40);
this.txt1.Multiline = true;
this.txt1.Name = "txt1";
this.txt1.ReadOnly = true;
this.txt1.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
this.txt1.Size = new System.Drawing.Size(480, 424);
this.txt1.TabIndex = 8;
this.txt1.Text = "";
// 
// Form1
// 
this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
this.ClientSize = new System.Drawing.Size(480, 462);
this.Controls.Add(this.txt1);
this.Controls.Add(this.txtpath);
this.Controls.Add(this.button2);
this.Controls.Add(this.button1);
this.Name = "Form1";
this.Text = "监视中.....";
((System.ComponentModel.ISupportInitialize)(this.fileSystemWatcher1)).EndInit();
this.ResumeLayout(false); }
#endregion /// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main() 
{
Application.Run(new Form1());
} private void fileSystemWatcher1_Created(object sender, System.IO.FileSystemEventArgs e)
{
 
txt1.Text+=e.FullPath.ToString()+ "已添加到你的目录中.\t";
 
} private void fileSystemWatcher1_Renamed(object sender, System.IO.RenamedEventArgs e)
{
txt1.Text+=e.OldFullPath.ToString() +"已经被重命名为:"+e.Name.ToString()+"\t";   } private void fileSystemWatcher1_Deleted(object sender, System.IO.FileSystemEventArgs e)
{
 
txt1.Text+=e.FullPath.ToString() +"已经被删除.\t";
 
} private void button1_Click(object sender, System.EventArgs e)
{
            txt1.Text="";  
} private void button2_Click(object sender, System.EventArgs e)
{
folderBrowserDialog1.ShowDialog();
txtpath.Text=folderBrowserDialog1.SelectedPath;
fileSystemWatcher1.Path = folderBrowserDialog1.SelectedPath;
}
}
}

Answer 2

FileSystemWatcher可以监听到文件变动。
想确定某个文件当前是否正在被写入应该是不可能的，但可以通过打开这个文件来判断此文件是否被其它程序占用。