四时宝库

Textreader和TextWriter是分别读取和写入文件的另一种方法，即使它们不是流类也是如此。 StreamReader和StreamWriter类分别从TextReader和TextWriter类派生。

Imports System.IO
Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
        Try
            Dim line As String
            Dim readFile As System.IO.TextReader = New _
				StreamReader("C:\TextReader.txt")
            While True
                line = readFile.ReadLine()
                If line Is Nothing Then
                    Exit While
                Else
                    MsgBox(line)
                End If
            End While
            readFile.Close()
            readFile = Nothing
        Catch ex As IOException
            MsgBox(ex.ToString)
        End Try
    End Sub
End Class

执行此程序时，TextReader逐行读取文件。