FileInfo.OpenWrite 方法

public:
 System::IO::FileStream ^ OpenWrite();

public System.IO.FileStream OpenWrite();

member this.OpenWrite : unit -> System.IO.FileStream

Public Function OpenWrite () As FileStream

返回

新文件或现有文件的仅写未共享 FileStream 对象。

例外

示例

以下示例打开一个用于写入的文件，然后从该文件中读取。

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;
//This is to test the OpenWrite method.

Imports System.IO
Imports System.Text

Public Class Test
    Public Shared Sub Main()
        Dim path As String = "c:\Temp\MyTest.txt"
        Dim fi As FileInfo = New FileInfo(path)
        Dim fs As FileStream

        ' Open the stream for writing.
        fs = fi.OpenWrite()
        Dim info As Byte() = _
            New UTF8Encoding(True).GetBytes("This is to test the OpenWrite method.")

        ' Add some information to the file.
        fs.Write(info, 0, info.Length)
        fs.Close()

        'Open the stream and read it back.
        fs = fi.OpenRead()
        Dim b(1023) As Byte
        Dim temp As UTF8Encoding = New UTF8Encoding(True)

        Do While fs.Read(b, 0, b.Length) > 0
            Console.WriteLine(temp.GetString(b))
        Loop
        fs.Close()
    End Sub
End Class
'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.
'
'
'
'
'
'
'
'
'
'
'
'

注解

如果文件路径已存在文件，则 OpenWrite 该方法将打开一个文件;如果文件路径不存在，则创建一个新文件。 对于现有文件，它不会将新文本追加到现有文本。 而是用新字符覆盖现有字符。 如果使用较短的字符串（如“这是 OpenWrite 方法的测试”）覆盖较长的字符串（如“第二次运行”），则文件将包含字符串的组合（“OpenWrite 方法的第二次运行测试”。