文本处理之-打开文件、保存文件

      vb.net提供了3种文本文件打开和保存的方法,FileOpen函数、StreamReader类和My命名空间。《Visual.Basic2008 step by Step》书中只提出了这三种方式如何打开文件和FileOpen函数保存文件,StreamReader类和My命名空间方式我也一同整理出来记在这里。

FileOpen函数打开和保存文件实例

Private Sub 打开文件OToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 打开文件OToolStripMenuItem.Click
       Dim AllText As String = "", LineOfText As String = ""
       OpenFileDialog1.Filter = "Text files (*.txt)|*.txt" '设置打开文件类型
       If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
           Try '使用错误处理程序捕获错误
               FileOpen(1, OpenFileDialog1.FileName, OpenMode.Input)
               Do Until EOF(1) '从文件中读取文本行
                   LineOfText = LineInput(1)
                   '逐行将文本添加到alltext变量中
                   AllText = AllText & LineOfText & vbCrLf
               Loop
                   TextBox1.Text = AllText
            Catch ex As Exception
               MsgBox("文件打开错误")
           Finally
               FileClose(1)
           End Try
       End If
End Sub

 

Private Sub 保存SToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 保存SToolStripMenuItem.Click
        SaveFileDialog1.Filter = "Text files (*.txt) | *.txt" '设置保存类型
        If SaveFileDialog1.ShowDialog = DialogResult.OK Then
            FileOpen(1, SaveFileDialog1.FileName, OpenMode.Output)
            PrintLine(1, TextBox1.Text)
            FileClose(1)
        End If
End Sub

 

StreamReader类打开和保存文件实例

Imports System
Imports System.IO
Imports System.Text.Encoding '字符空间

Private Sub 打开文件ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 打开文件ToolStripMenuItem.Click
    OpenFileDialog1.Filter = "Text files (*.txt)|*.txt" '设置打开文件类型
    Dim StreamtoDisplay As StreamReader
    If OpenFileDialog1.ShowDialog() = DialogResult.OK Then        
        StreamtoDisplay = New StreamReader(OpenFileDialog1.FileName, [Default]) '设置字符为系统默认字符,否则在处理中文时会出现乱码 
        TextBox1.Text = StreamtoDisplay.ReadToEnd
        StreamtoDisplay.Close()
        TextBox1.Select(0, 0)
    End If
End Sub

 

Private Sub 保存ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 保存ToolStripMenuItem.Click
    SaveFileDialog1.Filter = "Text files (*.txt) | *.txt" '设置保存类型
    Dim myStreamWriter As StreamWriter = New StreamWriter(SaveFileDialog1.FileName)
    If SaveFileDialog1.ShowDialog = DialogResult.OK Then
        myStreamWriter.Write(TextBox1.Text)
        myStreamWriter.Close()
    End If
End Sub

 

My命名空间打开和保存文件实例

Imports System
Imports System.Text.Encoding '字符空间

Private Sub 打开文件MycomputerfilesystemToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 打开文件MycomputerfilesystemToolStripMenuItem.Click
    OpenFileDialog1.Filter = "Text files (*.txt)|*.txt" '设置打开文件类型
    Dim AllText As String = ""
    If OpenFileDialog1.ShowDialog() = DialogResult.OK Then        
        AllText = My.Computer.FileSystem.ReadAllText(OpenFileDialog1.FileName, [Default]) '设置字符为系统默认字符,否则在处理中文时会出现乱码 
        TextBox1.Text = AllText
    End If
End Sub

Private Sub 保存MyComputerFileSystemToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 保存MyComputerFileSystemToolStripMenuItem.Click
    SaveFileDialog1.Filter = "Text files (*.txt) | *.txt"
    If SaveFileDialog1.ShowDialog = DialogResult.OK Then
        My.Computer.FileSystem.WriteAllText(SaveFileDialog1.FileName, TextBox1.Text, False) 'False参数,如果文件存在则覆盖文件,Ture参数,追加本文到文件
    End If
End Sub

posted @ 2011-12-11 20:59  cufish  阅读(280)  评论(0编辑  收藏  举报