Programmatically add controls to form

Question

I\'m using the attached code to add another line\\row of controls beneath an existing set (when a label is clicked). There could be quite a few rows added so I\'m having to repe

Answer 1

Hmmm.. UseVisualStyleBackColor says 'winforms' to me.

A few points...

Don't add controls all to one panel, use a usercontrol.

Then just add instances of that.

Don't process click events from a label

Use a linklabel or button. Anything else = being mean to users. Of course it makes sense to you, you thought of it! Now so with users, this is black and white.

Sample...

Very minimal of course. You'll want to:

• Put the items in a scrollable panel instead of right on the form.
• Add them to a generic list of uc probably, too.
• Set form's min/max size - to allow reasonable sizing (allow any height > ~100)
• Set uc's and controls .Anchor properties to allow reasonable resizing

uc.vb

Public Class uc
    Inherits System.Windows.Forms.UserControl

    Private components As System.ComponentModel.IContainer
    Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
    Friend WithEvents LinkLabel1 As System.Windows.Forms.LinkLabel

    Public Sub New()
        MyBase.New()

        Me.TextBox1 = New System.Windows.Forms.TextBox
        Me.LinkLabel1 = New System.Windows.Forms.LinkLabel
        Me.SuspendLayout()

        Me.TextBox1.Location = New System.Drawing.Point(8, 8)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.Size = New System.Drawing.Size(88, 20)
        Me.TextBox1.TabIndex = 0
        Me.TextBox1.Text = "TextBox1"

        Me.LinkLabel1.Enabled = False
        Me.LinkLabel1.Location = New System.Drawing.Point(112, 8)
        Me.LinkLabel1.Name = "LinkLabel1"
        Me.LinkLabel1.Size = New System.Drawing.Size(24, 16)
        Me.LinkLabel1.TabIndex = 1
        Me.LinkLabel1.TabStop = True
        Me.LinkLabel1.Text = "add"

        Me.Controls.Add(Me.LinkLabel1)
        Me.Controls.Add(Me.TextBox1)
        Me.Name = "uc"
        Me.Size = New System.Drawing.Size(148, 36)
        Me.ResumeLayout(False)

    End Sub

    Private _addcallback As EventHandler = Nothing
    Public Property AddCallback() As EventHandler
        Get
            Return _addcallback
        End Get
        Set(ByVal Value As EventHandler)

            _addcallback = Value
            LinkLabel1.Enabled = Not Value Is Nothing

        End Set
    End Property

    Private Sub LinkLabel1_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
        If AddCallback Is Nothing Then Throw New ApplicationException("AddCallback not set on a uc") ' ALWAYS check for errors like this 
        _addcallback(Me, Nothing)
        AddCallback = Nothing ' gray myself out, can't insert in thie implementation
    End Sub
End Class

frm.vb

Public Class frm
    Inherits System.Windows.Forms.Form

    Private components As System.ComponentModel.IContainer
    Public Sub New()
        MyBase.New()
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Name = "Form1"
        Me.Text = "Form1"
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        AddClicked(Me, Nothing)
    End Sub

    Private Sub AddClicked(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim myuc As New uc
        myuc.AddCallback = AddressOf AddClicked
        If Controls.Count > 0 Then
            myuc.Top = Controls(Controls.Count - 1).Bottom
        End If
        Me.Controls.Add(myuc)
    End Sub
End Class