FileInfo类
1.注解
FileInfo将 类用于典型的操作，例如复制、移动、重命名、创建、打开、删除和追加到文件。
如果对同一个文件执行多个操作，则使用FileInfo实例方法而不是类的相应静态方法File可能更有效，因为并不总是需要安全检查。
创建或打开文件时， FileInfo 许多方法返回其他 I/O 类型。 可以使用这些其他类型进一步操作文件。 有关详细信息，请参阅特定FileInfo成员，例如 Open、、OpenReadOpenText、 CreateText或 Create。
默认情况下，向所有用户授予对新文件的完整读/写访问权限。
2.属性
| Attributes | 获取或设置当前文件或目录的特性。(继承自 FileSystemInfo) |
|---|---|
| CreationTime | 获取或设置当前文件或目录的创建时间。(继承自 FileSystemInfo) |
| CreationTimeUtc | 获取或设置当前文件或目录的创建时间，其格式为协调世界时 (UTC)。(继承自 FileSystemInfo) |
| Directory | 获取父目录的实例。 |
| DirectoryName | 获取表示目录的完整路径的字符串。 |
| Exists | 获取指示文件是否存在的值。 |
| Extension | 获取文件名的扩展名部分，包括前导点 . （即使它是整个文件名）或空字符串（如果不存在扩展名）。(继承自 FileSystemInfo) |
| FullName | 获取目录或文件的完整目录。(继承自 FileSystemInfo) |
| IsReadOnly | 获取或设置确定当前文件是否为只读的值。 |
| LastAccessTime | 获取或设置上次访问当前文件或目录的时间。(继承自 FileSystemInfo) |
| LastAccessTimeUtc | 获取或设置上次访问当前文件或目录的时间，其格式为协调世界时 (UTC)。(继承自 FileSystemInfo) |
| LastWriteTime | 获取或设置上次写入当前文件或目录的时间。(继承自 FileSystemInfo) |
| LastWriteTimeUtc | 获取或设置上次写入当前文件或目录的时间，其格式为协调世界时 (UTC)。(继承自 FileSystemInfo) |
| Length | 获取当前文件的大小（以字节为单位）。 |
| LinkTarget | 获取位于 中的 FullName链接的目标路径，如果 null 此 FileSystemInfo 实例不表示链接，则获取 。(继承自 FileSystemInfo) |
| Name | 获取文件名。 |
| UnixFileMode | 获取或设置当前文件或目录的 Unix 文件模式。(继承自 FileSystemInfo) |
3.方法
4.常用属性
- Exists: 判断文件是否存在。
- Name: 获取文件的名称。
- FullName: 获取文件的完整路径。
- Directory: 获取文件所在的目录的实例。
- Exists: 判断文件是否存在。
- Extension: 获取文件的扩展名。
- Length: 获取文件的大小（字节数）。
- CreationTime: 获取文件的创建时间。
- LastAccessTime: 获取文件的上次访问时间。
- LastWriteTime: 获取文件的上次写入时间。
using System;
using System.IO;
class Program
{
static void Main()
{
// 指定文件路径
string filePath = @"C:\example\sample.txt";
// 创建一个 FileInfo 对象
FileInfo fileInfo = new FileInfo(filePath);
// 输出文件信息
if (fileInfo.Exists)
{
Console.WriteLine("文件存在！")
Console.WriteLine("文件名: " + fileInfo.Name);
Console.WriteLine("文件完整路径: " + fileInfo.FullName);
Console.WriteLine("文件所在目录: " + fileInfo.Directory);
Console.WriteLine("文件是否存在: " + fileInfo.Exists);
Console.WriteLine("文件扩展名: " + fileInfo.Extension);
Console.WriteLine("文件大小: " + fileInfo.Length + " 字节");
Console.WriteLine("文件创建时间: " + fileInfo.CreationTime);
Console.WriteLine("文件上次访问时间: " + fileInfo.LastAccessTime);
Console.WriteLine("文件上次写入时间: " + fileInfo.LastWriteTime);
}
else
{
Console.WriteLine("文件不存在！");
}
}
}
//文件存在！
//文件名: sample.txt
//文件完整路径: C:\example\sample.txt
//文件所在目录: C:\example
//文件是否存在: True
//文件扩展名: .txt
//文件大小: 1024 字节
//文件创建时间: 2024-04-21 10:30:00
//文件上次访问时间: 2024-04-21 11:15:00
//文件上次写入时间: 2024-04-21 11:20:00
5.常用方法
- System.IO.FileInfo CopyTo (string destFileName)将文件从一个位置复制到另一个位置。
using System;
using System.IO;
class Test
{
public static void Main()
{
string path = @"c:\SoureFile.txt";
string path2 = @"c:\NewFile.txt";
FileInfo fi1 = new FileInfo(path);
FileInfo fi2 = new FileInfo(path2);
try
{
// Create the source file.
using (FileStream fs = fi1.Create()) { }
//Ensure that the target file does not exist.
if (File.Exists(path2))
{
fi2.Delete();
}
//Copy the file.f
fi1.CopyTo(path2);
Console.WriteLine("{0} was copied to {1}.", path, path2);
}
catch (IOException ioex)
{
Console.WriteLine(ioex.Message);
}
}
}
- System.IO.FileStream Create() 创建一个新的空文件。
using System;
using System.IO;
public class DeleteTest
{
public static void Main()
{
// Create a reference to a file.
FileInfo fi = new FileInfo("temp.txt");
// Actually create the file.
FileStream fs = fi.Create();
// Modify the file as required, and then close the file.
fs.Close();
// Delete the file.
fi.Delete();
}
}
以下示例创建一个文件，向其中添加一些文本，并从该文件中读取。
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\MyTest.txt";
FileInfo fi = new FileInfo(path);
// Delete the file if it exists.
if (fi.Exists)
{
fi.Delete();
}
//Create the file.
using (FileStream fs = fi.Create())
{
Byte[] info =
new UTF8Encoding(true).GetBytes("This is some text in the file.");
//Add some information to the file.
fs.Write(info, 0, info.Length);
}
//Open the stream and read it back.
using (StreamReader sr = fi.OpenText())
{
string s = "";
while ((s = sr.ReadLine()) != null)
{
Console.WriteLine(s);
}
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
- void Delete() 删除文件。
using System;
using System.IO;
class Test
{
public static void Main()
{
string path = @"c:\MyTest.txt";
FileInfo fi1 = new FileInfo(path);
try
{
using (StreamWriter sw = fi1.CreateText()) {}
string path2 = path + "temp";
FileInfo fi2 = new FileInfo(path2);
//Ensure that the target does not exist.
fi2.Delete();
//Copy the file.
fi1.CopyTo(path2);
Console.WriteLine("{0} was copied to {1}.", path, path2);
//Delete the newly created file.
fi2.Delete();
Console.WriteLine("{0} was successfully deleted.", path2);
}
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//c:\MyTest.txt was copied to c:\MyTest.txttemp.
//c:\MyTest.txttemp was successfully deleted.
- void MoveTo(string destFileName) 将文件从一个位置移动到另一个位置。
fileInfo.MoveTo("C:\\NewLocation\\example.txt");
- System.IO.FileStream Open(System.IO.FileMode mode) 以指定模式打开文件，例如读取或写入文件内容。
//示例打开一个文件，向该文件添加一些信息，然后读取该文件。
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\MyTest.txt";
FileInfo fi = new FileInfo(path);
// Delete the file if it exists.
if (!fi.Exists)
{
//Create the file.
using (FileStream fs = fi.Create())
{
Byte[] info = new UTF8Encoding(true).GetBytes("This is some text in the file.");
//Add some information to the file.
fs.Write(info, 0, info.Length);
}
}
//Open the stream and read it back.
using (FileStream fs = fi.Open(FileMode.Open))
{
byte[] b = new byte[1024];
UTF8Encoding temp = new UTF8Encoding(true);
while (fs.Read(b,0,b.Length) > 0)
{
Console.WriteLine(temp.GetString(b));
}
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
- System.IO.FileStream OpenRead() 创建只读 FileStream
//以下示例以只读方式打开文件并从中读取数据。
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\MyTest.txt";
FileInfo fi = new FileInfo(path);
// Delete the file if it exists.
if (!fi.Exists)
{
//Create the file.
using (FileStream fs = fi.Create())
{
Byte[] info = new UTF8Encoding(true).GetBytes("This is some text in the file.");
//Add some information to the file.
fs.Write(info, 0, info.Length);
}
}
//Open the stream and read it back.
using (FileStream fs = fi.OpenRead())
{
byte[] b = new byte[1024];
UTF8Encoding temp = new UTF8Encoding(true);
while (fs.Read(b,0,b.Length) > 0)
{
Console.WriteLine(temp.GetString(b));
}
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is some text in the file.
//
//
//
//
//
//
//
//
//
//
//
//
- System.IO.FileStream OpenWrite() 创建一个只写的 FileStream
using System;
using System.IO;
using System.Text;
class Test
{
public static void Main()
{
string path = @"c:\Temp\MyTest.txt";
FileInfo fi = new FileInfo(path);
// Open the stream for writing.
using (FileStream fs = fi.OpenWrite())
{
Byte[] info =
new UTF8Encoding(true).GetBytes("This is to test the OpenWrite method.");
// Add some information to the file.
fs.Write(info, 0, info.Length);
}
// Open the stream and read it back.
using (FileStream fs = fi.OpenRead())
{
byte[] b = new byte[1024];
UTF8Encoding temp = new UTF8Encoding(true);
while (fs.Read(b,0,b.Length) > 0)
{
Console.WriteLine(temp.GetString(b));
}
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//This is to test the OpenWrite method.
//
//
//
//
//
//
//
//
//
//
//
- System.IO.StreamWriter CreateText 创建写入新文本文件的 StreamWriter。
using System;
using System.IO;
class Test
{
public static void Main()
{
string path = @"c:\temp\MyTest.txt";
FileInfo fi = new FileInfo(path);
if (!fi.Exists)
{
//Create a file to write to.
using (StreamWriter sw = fi.CreateText())
{
sw.WriteLine("Hello");
sw.WriteLine("And");
sw.WriteLine("Welcome");
}
}
//Open the file to read from.
using (StreamReader sr = fi.OpenText())
{
string s = "";
while ((s = sr.ReadLine()) != null)
{
Console.WriteLine(s);
}
}
}
}
//This code produces output similar to the following;
//results may vary based on the computer/file structure/etc.:
//
//Hello
//And
//Welcome
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