FileStream.CanSeek 屬性

定義

命名空間:

System.IO

組件:

System.Runtime.dll

來源:

FileStream.cs

取得值，表示目前資料流是否支援搜尋。

public:
 virtual property bool CanSeek { bool get(); };

public override bool CanSeek { get; }

member this.CanSeek : bool

Public Overrides ReadOnly Property CanSeek As Boolean

屬性值

Boolean

如果資料流支援搜尋，則為 true；如果資料流已關閉或如果 FileStream 是從作業系統控制代碼 (例如管道或主控台的輸出) 建構，則為 false。

範例

下列範例會 CanSeek 使用 屬性來檢查數據流是否支持搜尋。

using namespace System;
using namespace System::IO;
using namespace System::Text;

int main()
{
   String^ path = "c:\\temp\\MyTest.txt";
   
   // Delete the file if it exists.
   if ( File::Exists( path ) )
   {
      File::Delete( path );
   }

   //Create the file.
   FileStream^ fs = File::Create( path );
   try
   {
      if ( fs->CanSeek )
      {
         Console::WriteLine( "The stream connected to {0} is seekable.", path );
      }
      else
      {
         Console::WriteLine( "The stream connected to {0} is not seekable.", path );
      }
   }
   finally
   {
      if ( fs )
         delete (IDisposable^)fs;
   }
}

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

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

        // Delete the file if it exists.
        if (File.Exists(path))
        {
            File.Delete(path);
        }

        //Create the file.
        using (FileStream fs = File.Create(path))
        {
            if (fs.CanSeek)
            {
                Console.WriteLine("The stream connected to {0} is seekable.", path);
            }
            else
            {
                Console.WriteLine("The stream connected to {0} is not seekable.", path);
            }
        }
    }
}

open System.IO

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

// Delete the file if it exists.
if File.Exists path then
    File.Delete path


//Create the file.
do
    use fs = File.Create path

    if fs.CanSeek then
        printfn $"The stream connected to {path} is seekable."
    else
        printfn $"The stream connected to {path} is not seekable."

Imports System.IO

Public Class Test

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

        ' Delete the file if it exists.
        If File.Exists(path) Then
            File.Delete(path)
        End If

        'Create the file.
        Dim fs As FileStream = File.Create(path)

        If fs.CanSeek Then
            Console.WriteLine("The stream connected to {0} is seekable.", path)
        Else
            Console.WriteLine("The stream connected to {0} is not seekable.", path)
        End If

        fs.Close()
    End Sub
End Class

備註

如果衍生自 Stream 類別不支援搜尋，則呼叫Length、 SetLengthPosition和 Seek 會擲回 NotSupportedException。

如果資料流已關閉，這個屬性會傳 false回 。

另請參閱

• 檔案和資料流 I/O
• 作法：讀取檔案中的文字
• 作法：將文字寫入檔案