File.OpenRead(String) 方法

public:
 static System::IO::FileStream ^ OpenRead(System::String ^ path);

public static System.IO.FileStream OpenRead(string path);

static member OpenRead : string -> System.IO.FileStream

Public Shared Function OpenRead (path As String) As FileStream

參數

傳回

在指定路徑上只讀 FileStream 。

例外狀況

範例

以下範例開啟一個檔案進行讀取。

using System;
using System.IO;
using System.Text;

class Test
{
    public static void Main()
    {
        string path = @"c:\temp\MyTest.txt";

        if (!File.Exists(path))
        {
            // Create the file.
            using (FileStream fs = File.Create(path))
            {
                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 = File.OpenRead(path))
        {
            byte[] b = new byte[1024];
            UTF8Encoding temp = new UTF8Encoding(true);

            while (fs.Read(b,0,b.Length) > 0)
            {
                Console.WriteLine(temp.GetString(b));
            }
        }
    }
}

open System.IO
open System.Text

let path = @"c:\temp\MyTest.txt"

if File.Exists path |> not then
    // Create the file.
    use fs = File.Create path

    let info =
        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.
do
    use fs = File.OpenRead path
    let b = Array.zeroCreate 1024
    let temp = UTF8Encoding true

    while fs.Read(b, 0, b.Length) > 0 do
        printfn $"{temp.GetString b}"

Imports System.IO
Imports System.Text

Public Class Test
  Public Shared Sub Main()
    Dim path As String = "c:\temp\MyTest.txt"

    If Not File.Exists(path) Then
      ' Create the file.
      Using fs As FileStream = File.Create(path)
        Dim info As Byte() = New UTF8Encoding(True).GetBytes("This is some text in the file.")

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

    ' Open the stream and read it back.
    Using fs As FileStream = File.OpenRead(path)
      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
    End Using

  End Sub
End Class

備註

此方法等價FileStream(String, FileMode, FileAccess, FileShare)於構造子過載，其FileMode值為 Open、值FileAccessReadFileShare為 及 值為 。Read

path參數允許指定相對或絕對路徑資訊。 相對路徑資訊會被解讀為相對於目前工作目錄的相對於。 欲取得目前的工作目錄，請參見 GetCurrentDirectory。

關於常見 I/O 任務的清單，請參見 Common I/O 任務。

另請參閱

• 檔案和數據流 I/O
• 從檔案中閱讀文字
• 如何：將文字寫入檔案
• 如何：讀取和寫入新建立的數據檔