Derived TextBox

[Rob]

Question : I want to create a read only TextBox that does not
respond to any input from the keyboard, therefore I came up
with the following derived class :

Option Strict On

Imports System.Windows.Forms.TextBox

Public Class DerivedTextBox
Inherits TextBox

Protected Overridable Sub KeyEventHandler( _
ByVal sender As Object, _
ByVal e As KeyEventHandler)

End Sub

End Class


I then place this TextBox on my Form1 using the following :

Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

Public Sub New()
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call
Me.TextBox1.Show()
'
'TextBox1
'
Me.TextBox1.AutoSize = False
Me.TextBox1.Location = New System.Drawing.Point(8, 8)
Me.TextBox1.Multiline = True
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.ReadOnly = True
Me.TextBox1.Size = New System.Drawing.Size(230, 150)
Me.TextBox1.TabIndex = 1
Me.TextBox1.TabStop = False
Me.TextBox1.Text = ""
Me.TextBox1.Visible = True
End Sub

'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
Friend WithEvents TextBox1 As DerivedTextBox

However the TextBox remains invisible. How can I get
TextBox1 to appear on Form1 ?

 

[Ken Tucker [MVP]]

Hi,

I dont see where you added it to the form's controls.

Ken
------------------
Question : I want to create a read only TextBox that does not
respond to any input from the keyboard, therefore I came up
with the following derived class :

Option Strict On

Imports System.Windows.Forms.TextBox

Public Class DerivedTextBox
Inherits TextBox

Protected Overridable Sub KeyEventHandler( _
ByVal sender As Object, _
ByVal e As KeyEventHandler)

End Sub

End Class


I then place this TextBox on my Form1 using the following :

Public Class Form1
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

Public Sub New()
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call
Me.TextBox1.Show()
'
'TextBox1
'
Me.TextBox1.AutoSize = False
Me.TextBox1.Location = New System.Drawing.Point(8, 8)
Me.TextBox1.Multiline = True
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.ReadOnly = True
Me.TextBox1.Size = New System.Drawing.Size(230, 150)
Me.TextBox1.TabIndex = 1
Me.TextBox1.TabStop = False
Me.TextBox1.Text = ""
Me.TextBox1.Visible = True
End Sub

'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
Friend WithEvents TextBox1 As DerivedTextBox

However the TextBox remains invisible. How can I get
TextBox1 to appear on Form1 ?

 

[Rob]

Your right ! ! ! , I needed to make the following addition :
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1, Me.Button1, Me.TextBox1})

Unfortunately, I'm still back to square one, my TextBox1 still
responds to keyboard events. Is there a way to rewrite the
Class DerivedTextBox to prevent keyboard response ?

 

[Homer J Simpson]

Your right ! ! ! , I needed to make the following addition :

Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1,
Me.Button1, Me.TextBox1})

Unfortunately, I'm still back to square one, my TextBox1 still

responds to keyboard events. Is there a way to rewrite the
Class DerivedTextBox to prevent keyboard response ?

FWIW, I always try a label first for this. I'm assuming that won't work for
you?

Disabling shortcuts and making it readonly isn't enough?

 

[Cor Ligthert [MVP]]

Rob,

Why are you doing it this difficult. A label with a white background looks in my opinion the same.

Cor
"Rob" <[email protected]> schreef in bericht Your right ! ! ! , I needed to make the following addition :
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1, Me.Button1, Me.TextBox1})

Unfortunately, I'm still back to square one, my TextBox1 still
responds to keyboard events. Is there a way to rewrite the
Class DerivedTextBox to prevent keyboard response ?

 

[Cerebrus]

Hi Rob,

If you simply must use a TextBox, contrary to the wise suggestions of
Cor and Homer (who suggested using a label), you still don't have to
create a Derived class. Creating a derived textbox seems too much
effort to incorporate such basic functionality.

You just need to add the *normal* textbox to your form, and you could
set it's ReadOnly property to True. To make it even more
*unresponsive*, simply handle the Keypress and KeyDown events, and
within each set "e.Handled = True", where e is specific type of
EventArgs for each of the mentioned events.

Regards,

Cerebrus.

 

[Martin]

Well, I can understand that you would want to make this dependent on a
property, to simulate the 'Locked' state we used to have in VB6. That
allowed the control to take focus, and to navigate inside the textbox with
the arrow keys, but did not allow the user to make any changes.
I am looking myself for such a 'state' too, so I can set a property
dependent on the users' rights. Such a state would be ideal for users who
only have 'Read' rights.
Currently I use the ReadOnly property for this, but that is so ugly. I looks
like the control is disabled.

Martin


Rob,

Why are you doing it this difficult. A label with a white background looks
in my opinion the same.

Cor
"Rob" <[email protected]> schreef in bericht
Your right ! ! ! , I needed to make the following addition :
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1,
Me.Button1, Me.TextBox1})

Unfortunately, I'm still back to square one, my TextBox1 still
responds to keyboard events. Is there a way to rewrite the
Class DerivedTextBox to prevent keyboard response ?

 

[Cerebrus]

Hi,

Martin wrote :

Change the backcolor of the textbox back to normal, after you set it's
ReadOnly property to True. The normal behaviour is meant so that the
user gets a *visual* indication of the Readonly status. Else, users
would definitely try to type in the control a few times before
realizing that input is disabled, unless you give some other
indication.

Regards,

Cerebrus.

 

[Ken Tucker [MVP]]

Hi,

In the keypress event you need e.handled=true

Ken
---------------
Your right ! ! ! , I needed to make the following addition :
Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label1,
Me.Button1, Me.TextBox1})

Unfortunately, I'm still back to square one, my TextBox1 still
responds to keyboard events. Is there a way to rewrite the
Class DerivedTextBox to prevent keyboard response ?

 

[Martin]

Yup, that does the trick, so I will override the Readonly property in my
subclass to keep the original background color. That would also be the way
to go for Rob I think.

Thanks for your contribution

Martin

 

[Martin]

That makes me wonder... Why didn't MS put a ReadOnly property on other
controls, such as the combobox, checkbox and radiobutton? Now everybody who
needs that (and/or used it in VB6) has to re-invent the wheel all over
again.