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File Processing

File Processing . Creating & Reading Text Files. Storing Data in Text Files: With VB 2008. File>New Project> WindowsFormApplication (provide a project name) Highlight project name in Solution Explorer. Add>New Item Select Text File icon> provide name Type in data values, one per line

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File Processing

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  1. File Processing Creating & Reading Text Files

  2. Storing Data in Text Files: With VB 2008 • File>New Project>WindowsFormApplication • (provide a project name) • Highlight project name in Solution Explorer. • Add>New Item • Select Text File icon> provide name • Type in data values, one per line • Save All

  3. Data for text file: Payroll.txt Sandy Kinnery 9.35 35 Judy Mollica 10.75 33

  4. Problem: Calculate Payroll

  5. Syntax to Read in Data Sequentially from File Dim readerVar As IO.StreamReader readerVar = IO.File.OpenText(filespec) Varname = readerVar.ReadLine filespecmust include the full pathname unless the file is in ProjectFolderName/bin/Debug

  6. Code In Button Click-Event Dim readerVar As IO.StreamReader Dim strName As String Dim decHourlyWage As Decimal Dim decHoursWorked As Decimal Dim decSalary As Decimal readerVar = IO.File.OpenText("Payroll.txt")

  7. Read in Data from Text File strName = readerVar.ReadLine decHourlyWage = CDec(readerVar.ReadLine) decHoursWorked = CDec(readerVar.ReadLine) decSalary = decHourlyWage * decHoursWorked

  8. Display Results in a ListBox lstResults.Items.Add(strName & " " & _ FormatCurrency(decSalary)) readerVar.Close()

  9. Peek Method of StreamReader Class: Returns -1 when EOF • readerVar = IO.File.OpenText("Payroll.txt") Do While readerVar.Peek <> -1 strName = readerVar.ReadLine decHourlyWage = CDec(readerVar.ReadLine) decHoursWorked = CDec(readerVar.ReadLine) decSalary = decHourlyWage * decHoursWorked lstResults.Items.Add(strName & " " & _ FormatCurrency(decSalary)) Loop readerVar.Close()

  10. Text Readings • ListBox – pp. 294-299 • Text Files – pp. 658-671 • Not exactly what we’ve done today

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