Represents a reader that can read a sequential series of characters.
Assembly: mscorlib (in mscorlib.dll)
Thetype exposes the following members.
|Close||Closes the and releases any system resources associated with the TextReader.|
|CreateObjRef||Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)|
|Dispose||Releases all resources used by the object.|
|Dispose(Boolean)||Releases the unmanaged resources used by the and optionally releases the managed resources.|
|Equals(Object)||Determines whether the specified object is equal to the current object. (Inherited from Object.)|
|Finalize||Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)|
|GetHashCode||Serves as the default hash function. (Inherited from Object.)|
|GetLifetimeService||Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|InitializeLifetimeService||Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)|
|MemberwiseClone||Creates a shallow copy of the current Object. (Inherited from Object.)|
|MemberwiseClone(Boolean)||Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)|
|Peek||Reads the next character without changing the state of the reader or the character source. Returns the next available character without actually reading it from the reader.|
|Read||Reads the next character from the text reader and advances the character position by one character.|
|Read(Char(), Int32, Int32)||Reads a specified maximum number of characters from the current reader and writes the data to a buffer, beginning at the specified index.|
|ReadAsync||Reads a specified maximum number of characters from the current text reader asynchronously and writes the data to a buffer, beginning at the specified index.|
|ReadBlock||Reads a specified maximum number of characters from the current text reader and writes the data to a buffer, beginning at the specified index.|
|ReadBlockAsync||Reads a specified maximum number of characters from the current text reader asynchronously and writes the data to a buffer, beginning at the specified index.|
|ReadLine||Reads a line of characters from the text reader and returns the data as a string.|
|ReadLineAsync||Reads a line of characters asynchronously and returns the data as a string.|
|ReadToEnd||Reads all characters from the current position to the end of the text reader and returns them as one string.|
|ReadToEndAsync||Reads all characters from the current position to the end of the text reader asynchronously and returns them as one string.|
|Synchronized||Creates a thread-safe wrapper around the specified TextReader.|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
is the abstract base class of StreamReader and StringReader, which read characters from streams and strings, respectively. Use these derived classes to open a text file for reading a specified range of characters, or to create a reader based on an existing stream.
This type implements the IDisposable interface. When you have finished using any type that derives from this type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see Dispose and the “Using an Object that Implements IDisposable” section in the IDisposable interface topic.
The class is an abstract class. Therefore, you do not instantiate it in your code. The StreamReader class derives from and provides implementations of the members for reading from a stream. The following example shows how to read all the characters in a file by using the StreamReader.ReadAsync(Char(), Int32, Int32) method. It checks whether each character is a letter, digit, or white space before adding the character to an instance of the StringBuilder class.
Imports System.Text Imports System.IO Class MainWindow Private Async Sub Button_Click_1(sender As Object, e As RoutedEventArgs) Dim filename As String = "C:\Example\existingfile.txt" Dim result() As Char Dim builder As StringBuilder = New StringBuilder() Using reader As StreamReader = File.OpenText(filename) ReDim result(reader.BaseStream.Length) Await reader.ReadAsync(result, 0, reader.BaseStream.Length) End Using For Each c As Char In result If (Char.IsLetterOrDigit(c) Or Char.IsWhiteSpace(c)) Then builder.Append(c) End If Next FileOutput.Text = builder.ToString() End Sub End Class
.NET FrameworkSupported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)