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What is the syntax to display the contents of a simple text file to a listbox?

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Dani AI

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Nice, — that approach is the usual quick win. A few practical notes to make it robust for ASP.NET + VB.NET (and to avoid common gotchas):

  • Map the virtual path (use Server.MapPath) so the app finds the file on the server.
  • Check that the file exists and catch IO exceptions so the page does not error for missing/unreadable files.
  • Explicitly bind the data in WebForms (call DataBind) — WinForms ListBox behaves differently (it will show items when DataSource is set).
  • For large files prefer streaming (do not load the entire file into memory).

Example pattern for an ASP.NET WebForms page (VB.NET):

Dim filePath As String = Server.MapPath("~/App_Data/stocks.txt")

If System.IO.File.Exists(filePath) Then
    Try
        Dim text As String = System.IO.File.ReadAllText(filePath, System.Text.Encoding.UTF8)
        Dim lines As String() = text.Split(New String() {vbCrLf, vbLf}, StringSplitOptions.RemoveEmptyEntries)
        lstDisplay.DataSource = lines
        lstDisplay.DataBind()
    Catch ex As System.IO.IOException
        ' log or show friendly message
    End Try
End If

For very large files use a streaming enumerable (see File.ReadLines) to avoid high memory use: File.ReadLines documentation. Also keep files in a safe location such as App_Data, ensure the ASP.NET worker identity has read permission, and never bind user-supplied paths directly without validation to prevent path traversal.

Member Avatar for bpacheco1227

I figured it out.

lstdisplay.DataSource = IO.File.ReadAllLines(path & "stocks.txt")
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