OK! now we had learn about how to use directoryinfo class and now we shall learn about how to read and write a file! use streamwrite class subclass fileinfo subclass createtext and appendtext class to create a file and use append to add text to text file with its content! and then use streamreader and opentext to read file other detail we shall talk about at class! hope you can read the .ppt file first! learn about how to create file and open file and read and add text to file! have fun with it!

Public Class Form1

        If tmpfile <> "" Then

            ListBox1.Items.Add(tmpfile)

        End If

            tmpfile = Dir()

            If tmpfile <> "" Then

                ListBox1.Items.Add(tmpfile)

            End If

        Loop

        TextBox1.Text = ""

    End Sub

        Dim fileNum As Integer

        Dim counter As Integer = 0

        Dim str1 As String

        Dim filename As String

            str1 = ""

            Try

                fileNum = FreeFile() ' 取得檔案編號

                filename = Label1.Text & "\" & TextBox2.Text

                FileOpen(fileNum, filename, OpenMode.Input)

                Do Until EOF(fileNum) ' 讀取文字檔案內容

                    ' 讀取行

                    str1 &= LineInput(fileNum) & vbNewLine

                    counter += 1

                Loop

                FileClose(fileNum)

                Label4.Text = "總共 : " & counter & " 行"

                TextBox1.Text = str1

            Catch ex As Exception

                MsgBox("錯誤: 檔案不存在!")

            End Try

        Else

            MessageBox.Show("請點選檔案 !")

        Application.Exit()

        Dim fileNum As Integer

        Dim counter As Integer = 0

        Dim strContent As String = ""

        Dim filename As String

        If TextBox2.Text <> "" Then

            Try

                fileNum = FreeFile() ' 取得檔案編號

                filename = Label1.Text & "\" & TextBox2.Text

                FileOpen(fileNum, filename, OpenMode.Input)

                Do Until EOF(fileNum) ' 讀取文字檔案內容

                    ' 讀取行

                    strContent &= LineInput(fileNum) & vbNewLine

                    counter += 1

                Loop

                FileClose(fileNum)

                Label4.Text = "總共 : " & counter & " 行"

                TextBox1.Text = strContent

            Catch ex As Exception

                MsgBox("錯誤: 檔案不存在!")

            End Try

        Else

            MessageBox.Show("請點選檔案 !")

        Dim fileNum As Integer

        Dim fileName As String

            fileName = Label1.Text & "\" & TextBox2.Text

            fileNum = FreeFile() ' 取得檔案編號

            FileOpen(fileNum, fileName, OpenMode.Output)

            PrintLine(fileNum, TextBox1.Text) ' 寫入

            FileClose(fileNum)

        Else

            MessageBox.Show("資料不可空白 !")

        End If

End Class

next time we shall try to use random file to do the file function!