Determine position of cursor in TextBox ??

[jfortes]

Hi,

I've a huge file displayed on TextBox. The user is allowed to navigate inside of it with cursor.

What I need is to determine and display the position of the cursor, inside the TextBox, as it moves.

Any ideas ?

Thanks,
Joao.

[Deepak Sakpal]

u mean line number and column number ?

[jfortes]

Just column number.

Joao

[jmcilhinney]

You would do something like this, although this will definitely need refinement:

Dim columnIndex As Integer = myTextBox.SelectionStart
Dim lineIndex As Integer = 0
 
While columnIndex > myTextBox.Lines(lineIndex).Length
    columnIndex -= myTextBox.Lines(lineIndex).Length + 2
    lineIndex += 1
End While

When the loop exits the actual column index should be contained in the columnIndex property. I think this code palys up a bit if there are empty lines though. Anyway, you get the general idea, so you can play with it and work out the kinks.

[jfortes]

Thanks, gonna try it.

But which event triggers this action ?
Tried with TextBox39.TextChanged, but it only shows the position if any character is changed within the TextBox.

Is there an event generated when mouse moves inside the TextBox ?

[jmcilhinney]

I'd suggest that you put that code in a method and call it on the Click and KeyUp events. That way it will be executed whenever the caret position changes, which can happen if the TextBox is clicked, the user types a character or they use an arrow key. Unfortunately a KeyPress event is not raised when using the arrow keys so you must use KeyUp instead, e.g.

Private Sub SetColumnIndex()
        Dim columnIndex As Integer = Me.TextBox1.SelectionStart
        Dim lineIndex As Integer = 0
 
        While columnIndex > Me.TextBox1.Lines(lineIndex).Length
            columnIndex -= Me.TextBox1.Lines(lineIndex).Length + 2
            lineIndex += 1
        End While
 
        Me.Label1.Text = columnIndex.ToString()
    End Sub
 
    Private Sub TextBox1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.Click
        Me.SetColumnIndex()
    End Sub
 
    Private Sub TextBox1_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyUp
        Me.SetColumnIndex()
    End Sub

[jfortes]

Great solution. It works perfectly.
Thanks so much jmcilhinney.

Joao

[jmcilhinney]

Cool. Don't forget to resolve your thread from the Thread Tools menu.