This code demonstrates how to add controls to a form at run time. The number of rows and columns, the spacing between the controls and the size of the controls are all determined by Consts, but this could easily be changed so that the parameters are user entered. My example adds two handlers to each textbox. I will be posting a refinement to this that uses a TableLayoutPanel to position the controls. Suggestions on how to improve this code are always welcome.
' ' Name: ' ' DynamicTextBoxes ' ' Description: ' ' Simple example of how to create and use textboxes at run time. The number of rows and ' columns of textboxes are defined by ROWS and COLS. The spacing between controls is defined ' by XPAD and YPAD. The control size is defined by TBWIDTH and TBHEIGHT and the location of ' the control at the top left is defined by XSTART and YSTART. ' ' Audit: ' ' 2012-05-20 Reverend Jim ' Public Class Form1 Const XPAD = 5 'horizontal spacing between controls Const YPAD = 5 'vertical spacing between controls Const ROWS = 5 'number of rows of textboxes Const COLS = 5 'number of columns of textboxes Const TBWIDTH = 100 'text box width Const TBHEIGHT = 20 'text box height Const XSTART = 10 'x position of first text box Const YSTART = 10 'y position of first text box Private boxes(ROWS, COLS) As TextBox Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load Dim newbox As TextBox 'create a grid of textboxes For row As Integer = 0 To ROWS - 1 For col As Integer = 0 To COLS - 1 'calculate the position of the nex textbox Dim xpos As Integer = XSTART + row * (XPAD + TBWIDTH) Dim ypos As Integer = YSTART + col * (YPAD + TBHEIGHT) 'create a new textbox and set its properties newbox = New TextBox newbox.Size = New Drawing.Size(TBWIDTH, TBHEIGHT) newbox.Location = New Point(xpos, ypos) newbox.Name = "TextBox" & row & "_" & col newbox.Text = newbox.Name 'connect it to handlers, save a reference to the array and add it to the form controls AddHandler newbox.TextChanged, AddressOf TextBox_TextChanged AddHandler newbox.Enter, AddressOf TextBox_Enter boxes(row, col) = newbox Me.Controls.Add(newbox) Next Next End Sub Private Sub TextBox_TextChanged(sender As System.Object, e As System.EventArgs) 'when you modify the contents of any textbox, the name of that textbox and 'its current contents will be displayed in the title bar Dim box As TextBox = DirectCast(sender, TextBox) Me.Text = box.Name & ": " & box.Text End Sub Private Sub TextBox_Enter(sender As System.Object, e As System.EventArgs) 'when you enter a textbox control, its current contents will be displayed 'in the title bar Dim box As TextBox = DirectCast(sender, TextBox) Me.Text = box.Name & ": " & box.Text End Sub End Class
I completed my Computer Science degree at the University of Manitoba in 1976. I did two and a half years of programming in medical research followed by twenty-nine years at Manitoba Hydro (electric utility). Most of that was spent on doing development and maintenance on an AGC/SCADA (real-time programming/process control) system. The last ten years of that was spent doing application and infrastructure support and development. I have programmed in FORTRAN (mostly), APL, PL/1, COBOL, Lisp, SNOBOL, ALGOL, Assembler (several flavours), C, C++, Paradox, VB, vbScript and more recently, Python. I am married with two grown children of whom I am very proud, and a most beautiful wife. I am currently retired (and loving it).