Files in Visual Basic

This example will read in a CSV (comma separated values) with the name and year born of a person. As the file is read in the name of the person will be added to a combo box and the year born will be added to an array.

When the user selects a name from the combo box, it will display the year born.

The file: Copy the list of names and years and save it as C:/myData/names.txt. If you save it to a different location, be sure to change the code to your location


The "Lookup" Program
This program reads the file shown above. Each line in the file is added to the ComboBox combobox and displayed.

  1. Start a new Windows application, name it LookupFile.
  2. Add a ComboBox combobox to the form. Name it CboNames.
  3. Add a label label named lblInfo.
  4. Add the following code to form load:
Public Class Form1
    Dim Years(1) As Integer
    Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Dim S As String = ""
        Dim Count As Integer = 0
        FileOpen(1, "C:\myData\names.txt", OpenMode.Input) 'open the file for input
        While Not EOF(1) 'EOF=End of file, this loops to read all recordds
            S = LineInput(1) 'read from file 1
            Dim words As String() = S.Split(",")
            Me.CboNames.Items.Add(words(0)) 'add the name read to the combo box
            ReDim Preserve Years(Count) 'make the array Years big enough to hold the new year
            Years(Count) = words(1) 'the year born
            Count = Count + 1
        End While
        FileClose(1) 'close file 1
        If Me.CboNames.Items.Count > 0 Then 'make sure the file was read
            Me.CboNames.SelectedIndex = 0 'display 1st item in list
        End If
    End Sub

    Private Sub CboNames_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles CboNames.SelectedIndexChanged
        Dim num As Integer = CboNames.SelectedIndex
        Dim ThisYear As Integer = DateTime.Today.Year
        Dim Age As Integer = ThisYear - Years(num)
        Me.LblInfo.Text = CboNames.SelectedItem & " will be " & Age & " in " & ThisYear
    End Sub
End Class


Add more names to the list.

Use the example to create acompletely different lookup program.

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