Member Avatar for Gus_19

I was wondering if anyone knew of a good tutorial for parsing data from a text file and then populating the data into multiple text boxes. I have a text file with information pertaining to my form. The text file consists of key identifiers for each piece of information needed and I was wondering how to programmatically fill in my form by parsing that data.

  • 4 Contributors
  • 5 Replies
  • 226 Views
  • 11 Hours Discussion Span
  • Latest Post Latest Post by Begginnerdev

Dani AI

Generated

Short, practical pattern that fits the situation described by : keep the file as simple key/value lines (example: FirstName=John) and parse it line‑by‑line. Map keys to controls either by control Name (e.g. txtFirstName) or, more robustly, by using each control’s Tag to hold the key. That avoids brittle naming conventions and makes it easy to reuse the same parser for nested containers. ’s question about line-by-line parsing is exactly the right direction; read the file one line at a time and split at the first separator.

Below is a compact WinForms VB.NET approach: read lines, ignore blanks/comments, split at the first =, find a control by Tag (recursive) or fallback to Controls.Find, and set the control’s text or combo selection. is correct that many controls accept .Text, but for ComboBox it’s often better to set SelectedItem/SelectedIndex (or SelectedValue for data-bound lists) when possible.

Sub LoadFormFromFile(filePath As String)
    If Not IO.File.Exists(filePath) Then Return
    For Each rawLine In IO.File.ReadAllLines(filePath)
        Dim line = rawLine.Trim()
        If line = "" OrElse line.StartsWith("#") Then Continue For
        Dim i = line.IndexOf("="c)
        If i < 0 Then Continue For
        Dim key = line.Substring(0, i).Trim()
        Dim value = line.Substring(i + 1).Trim()
        Dim ctrl = FindControlByTag(Me, key)
        If ctrl Is Nothing Then
            Dim found = Me.Controls.Find(key, True)
            If found.Length > 0 Then ctrl = found(0)
        End If
        If ctrl IsNot Nothing Then
            If TypeOf ctrl Is ComboBox Then
                Dim cb = DirectCast(ctrl, ComboBox)
                If cb.Items.Contains(value) Then cb.SelectedItem = value Else cb.Text = value
            Else
                ctrl.Text = value
            End If
        End If
    Next
End Sub

Function FindControlByTag(parent As Control, tagValue As String) As Control
    For Each c As Control In parent.Controls
        If c.Tag IsNot Nothing AndAlso String.Equals(c.Tag.ToString(), tagValue, StringComparison.OrdinalIgnoreCase) Then Return c
        Dim child = FindControlByTag(c, tagValue)
        If child IsNot Nothing Then Return child
    Next
    Return Nothing
End Function

Troubleshooting notes: split at the first = so values can contain =; trim quotes/whitespace; handle encoding and FileNotFound; log missing keys; if combo boxes are data‑bound set SelectedValue rather than Items.Contains; for complex forms consider a key→control dictionary built at startup. These practices keep the parser simple and reliable.

Recommended Answers

All 5 Replies

Member Avatar for thines01

There are plenty of examples on this site and on the web.
What, specifically, is giving you trouble?

Member Avatar for Gus_19

I'm a little confused as to assigning the data behind the key identifier to the specific text/combo box

Member Avatar for movingcompany

Sorry i have no idea about your problem.

Member Avatar for thines01

You can typically use the .Text property of the combo box to populate it with content.

Member Avatar for Begginnerdev

There are a number of ways to do what thines is saying.

Are you parseing the data in line by line or the entire file?

Are you storing the data in a single string or in an array?

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.