I am using VB 2010. I have 20 TextBox controls in my form. I turned them to TextBox array.
Here is the code:
Dim TbArray(19) As TextBox
Private Sub Form7_Load(ByVal sender As System.Object,
ByVal e As System.EventArgs) Handles MyBase.Load
TbArray(0) = TextBox1
TbArray(1) = TextBox2
...
TbArray(19) = TextBox20
It works properly. I want my program to select all the text on the TextBox control which got focused.
How can i know which TextBox control has been selected? I mean there is no Private Sub TbArray(i)_GotFocus in the dropdown menu of vb designer.
To expound on what Akram said,
For x = 0 to 19
AddHandler tbarray(x).GotFocus, AddressOf TextBox_GotFocus
Next x
Private Sub TextBox_GotFocus(sender As Object, e As System.EventArgs)
Dim tb As TextBox = CType(sender, TextBox)
tb.SelectAll()
End Sub
Handle the TextBox.GotFocus event of all the TextBox controls using one event handler method. Use the following:
Dim focusedTextBox as TextBox = CType(sender, TextBox)
So you want the text inside the TextBox to get highlighted when it gets focus? Sounds like a job for JavaScript to me. Should be fairly simple using jQuery or something similar
Related
I have a vb.net form in which i added a GroupBox including 10 TextBox. I want to disable 9 TextBox at the load time and a single TextBox should be enable.
Normally you would be required to show what you have tried. Next time please do that.
Create an array of the text boxes you want to disable. Then loop to the array setting each box's enabled property to False.
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim boxes = {TextBox1, TextBox2}
For Each tb In boxes
tb.Enabled = False
Next
End Sub
I have a generic message box where we have a few panels in which we add controls at runtime.
Here in my form, I've already pnlBottom on which pnlButtons is there along with some other controls.
Now at run time I'm adding an OK button to pnlButtons which is there on pnlBottom. I'm not setting a TabIndex for any controls in the Designer.vb file.
I'm trying to keep the focus on the OK button using the code below, but it's not working.
For Each control As Control In Me.Controls
If TypeOf (control) Is Panel Then
Dim pnlBottons As Panel = CType(control, Panel)
If pnlBottons.Name = "pnlBottom" Then
For Each ctrl As Control In control.Controls
Dim pnlButtons As Panel = CType(ctrl, Panel)
If pnlButtons.Name = "pnlButtons" Then
For Each ctrlbtn As Control In ctrl.Controls
If TypeOf (ctrlbtn) Is Button Then
Dim textBox As Button = CType(ctrlbtn, Button)
textBox.Parent.Parent.TabIndex = 0
textBox.Parent.TabIndex = 0
textBox.TabIndex = 0
End If
Next
End If
Next
End If
End If
Next
Here I'm setting the TabIndex for pnlBottom, pnlButtons and OK button as 0.
Please suggest how to focus the OK button.
You can set the focus on a control during Form Load event using either of the following options. (Ref: How to set the focus on a control when the form loads in Visual Basic .NET or in Visual Basic 2005. The original link is broken, so use Wayback Machine.)
1- Control.Select Method
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Mybase.Load
Me.OKButton.Select()
End Sub
Focus is a low-level method intended primarily for custom control
authors. Instead, application programmers should use the Select method
or the ActiveControl property for child controls, or the Activate
method for forms.
2- Form.ActiveControl Property
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Mybase.Load
Me.ActiveControl = Me.OKButton
End Sub
3- Control.Focus Method
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Mybase.Load
Me.Show()
Me.OKButton.Focus()
End Sub
The reason that we call Me.Show() is to set forms visible to true. according to:
You can use the Control.Focus method in the Load event of the form to
set the focus on a control only after the Visible property of the form
is set to True.
In cases you can not use Me.OKButton you can find the control you want like this:
Dim control = Me.Controls.Find("OKButton", True).FirstOrDefault()
If Not control Is Nothing Then
control.Select() 'or other stuff
End If
I want to add the same event on my multiple textboxes. Let's say for example I want all my textboxes to trim the text value of itself when it has lost focus
my idea is to loop through all the textboxes and to add an event handler to all of it, but how will I refer to the textbox itself, I think it is the same as using the "this" keyword, but it is not available in vb.net - any other recommendations?
In order to get the element which triggered the event you can use the sender parameter of the event and cast it to the required type. It is not clear from the question which platform you are using, but below is the sample code for Windows Forms:
Private Sub txt1_TextChanged(sender As Object, e As EventArgs) Handles txt1.TextChanged
Dim currentTextbox as TextBox = CType(sender, TextBox)
' Do what you want with the textbox
End Sub
Similar principles should apply to Web forms or WPF as well.
Through all the textboxes Use handles for all textboxes
Private Sub TextBox1_LostFocus(sender As Object, e As EventArgs) _
Handles TextBox1.LostFocus, TextBox2.LostFocus
Dim txtBox As TextBox = sender
txtBox.Text = Strings.Trim(txtBox.Text)
End Sub
I do know how to handle event of textboxes in my form. But want to make this code shorter because I will 30 textboxes. It's inefficient to use this:
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged, TextBox4.TextChanged, TextBox5.TextChanged, TextBox6.TextChanged, TextBox7.TextChanged, TextBox8.TextChanged, TextBox9.TextChanged, TextBox10.TextChanged
Dim tb As TextBox = CType(sender, TextBox)
Select Case tb.Name
Case "TextBox1"
MsgBox(tb.Text)
Case "TextBox2"
MsgBox(tb.Text)
End Select
End Sub
Is there a way to shorten the handler?
You can use Controls.OfType + AddHandler programmatically. For example:
Dim textBoxes = Me.Controls.OfType(Of TextBox)()
For Each txt In textBoxes
AddHandler txt.TextChanged, AddressOf txtTextChanged
Next
one handler for all:
Private Sub txtTextChanged(sender As Object, e As EventArgs)
Dim txt = DirectCast(sender, TextBox)
Select Case txt.Name
Case "TextBox1"
MsgBox(txt.Text)
Case "TextBox2"
MsgBox(txt.Text)
End Select
End Sub
If you have created very Textbox with the Designer, I don't think there is a better method.
But, if you have created the Textboxes dynamically, you should AddHandler in this way:
For i = 0 to 30
Dim TB as New Texbox
AddHandler TB.TextChanged, TextBox1_TextChanged
'Set every Property that you need
Me.Controls.Add(TB)
Next
Say If you are having that 30 textboxes inside a panel(PnlTextBoxes), Now you can create handler for your textboxes dynamically like this below
For each ctrl in PnlTextBoxes.controls
If TypeOf ctrl is TextBox then
AddHandler ctrl.TextChanged, AddressOf CommonClickHandler
end if
Next
Private Sub CommonHandler(ByVal sender As System.Object, _
ByVal e As System.EventArgs)
MsgBox(ctype(sender,TextBox).Text)
End Sub
The best way would be to inherit from TextBox, override its OnTextChanged method to add your custom handling code, and then use that on your form(s) instead of the built-in TextBox control.
That way, all of the event handling code is in one single place and you increase abstraction. The behavior follows and is defined within the control class itself, not the form that contains the control. And of course, it frees you from having a bunch of ugly, hard-to-maintain Handles statements, or worse, slow and even uglier For loops.
For example, add this code defining a new custom text box control to a new file in your project:
Public Class CustomTextBox : Inherits TextBox
Protected Overridable Sub OnTextChanged(e As EventArgs)
' Do whatever you want to do here...
MsgBox(Me.Text)
' Call the base class implementation for default behavior.
' (If you don't call this, the TextChanged event will never be raised!)
MyBase.OnTextChanged(e)
End Sub
End Class
Then, after you recompile, you should be able to replace your existing TextBox controls with the newly-defined CustomTextBox control that has all of your behavior built in.
In VB6 there is a feature called Control Arrays, where you name controls the same name and provide them an index value. This allows you to set a value by looping through the controls and setting each value. In VB .NET I can't create a control array could someone provide me with a similar solution.
Here is a sample I wrote for something else that shows how to do something similar and shows how to do the handler as well. This makes a 10x10 grid of buttons that turn red when you click them.
Dim IsCreated(99) As Boolean
Dim Buttons As New Dictionary(Of String, Button)
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
For i As Integer = 0 To 99
Dim B As New Button
Me.Controls.Add(B)
B.Height = 30
B.Width = 40
B.Left = (i Mod 10) * 41
B.Top = (i \ 10) * 31
B.Text = Chr((i \ 10) + Asc("A")) & i Mod 10 + 1
Buttons.Add(B.Text, B)
B.Tag = i
AddHandler B.Click, AddressOf Button_Click
Next
End Sub
Private Sub Button_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim B As Button = sender
IsCreated(B.Tag) = True
B.BackColor = Color.Red
End Sub
Avoid using the proposed iteration approaches, you'll get a fairly random collection of controls unless your form is very simple. Simply declare the control array in your code and initialize it in the form constructor. Like this:
Public Class Form1
Private OrderNumbers() As TextBox
Public Sub New()
InitializeComponent()
OrderNumbers = New TextBox() {TextBox1, TextBox2}
End Sub
End Class
You can now treat OrderNumbers just like you could in VB6.
Maybe this is simpler. To create a control array, I put the control array declaration in a module. For example, if I have a Form with three TextBoxes and I want the TextBoxes to be part of a control array called 'mytext', I declare my control array in a module as follows:
Module Module1
Public mytext() As TextBox = {Form1.TextBox1, Form1.TextBox2, Form1.TextBox3}
End Module
And, I use the TextBoxes from the control array as follows:
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
mytext(0).Text = "Hello"
mytext(1).Text = "Hi"
mytext(2).Text = "There"
End Sub
End Class
You can even loop through the control array, like you could in VB6:
Public Class Form1
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
For i As Integer = 0 To 2
mytext(i).Text = i + 1
Next
End Sub
End Class
The beauty of using a module is that the TextBoxes do not even need to be in the same form.
With Winforms, you could do this:
myForm.Controls _
.OfType(Of TextBox) _
.OrderBy(Function(c) c.Name) _
.Where(Function(c) c.Name.StartsWith("somePrefix")) _
.ToArray()
On your form you would name your textboxes somePrefix1, somePrefix2, etc.
Here is an old article but it could give you more information. The top method is super easy.
Your Form, or PanelControl, or anything else that can contain child controls will have a Property called Controls.
You can loop through all of the text boxes in a control by using
'Create a List of TextBoxes, like an Array but better
Dim myTextBoxControls As New List
For Each uxControl As UserControl in MyFormName.Controls
If TypeOf(uControl) is TextBox
myTextBoxControls.Add(uControl)
End IF
Next
Now you have your iterate-able collection you can work with.
You can access a TextBoxes value with the EditValue property.
After looking at what you're trying to do a little further.
You probably want to name all of your controls with a Prefix, let's say abc for now.
For Each uxControl As UserControl in MyFormName.Controls
If TypeOf(uControl) is TextBox Then
Dim tbControl As TextBox = DirectCast(uControl, TextBox)
If tbControl.Name.StartsWith("abc") Then
tbControl.EditValue = "the Value you want to initialize"
End If
End If
Next
So this is one of the features that did not make the transition to VB.NET -- exactly :-( However, you can accomplish much of what you would have done in VB6 with two different mechanisms in .NET: Looping through the controls collection and handling control events.
Looping Through the Controls Collection
In VB.NET every form and control container has a controls collection. This is a collection that you can loop through and then do an operation on the control like set the value.
Dim myTxt As TextBox
For Each ctl As Control In Me.Controls
If TypeOf ctl Is TextBox Then
myTxt = CType(ctl, TextBox)
myTxt.Text = "something"
End If
Next
In this code sample you iterate over the controls collection testing the type of the returned object. If you find a textbox, cast it to a textbox and then do something with it.
Handling Control Events
You can also handle events over multiple controls with one event handler like you would have using the control array in VB6. To do this you will use the Handles keyword.
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged, TextBox3.TextChanged
Dim myTxt As TextBox = CType(sender, TextBox)
MessageBox.Show(myTxt.Text)
End Sub
The key here is the Handles keyword on the end of the event handler. You separate out the various controls that you want to handle and the event by using a comma. Make sure that you are handling controls that have the same event declaration. If you ever wondered what sender was for on every event well here's one of the uses for it. Cast the sender argument to the type of control that you are working with and assign it to a local variable. You will then be able to access and manipulate the control that fired the event just like you would have in VB6 if you specified and index to the array.
Using these two techniques you can replicate the functionality of control arrays in VB6. Good luck.
Private Sub Button3_Click(sender As System.Object, e As System.EventArgs) Handles Button3.Click
Dim a() As Control = GetControls("textbox")
For Each c As TextBox In a
c.Text = c.Name
Next
End Sub
Private Function GetControls(typeOfControl As String) As Control()
Dim allControls As New List(Of Control)
'this loop will get all the controls on the form
'no matter what the level of container nesting
'thanks to jmcilhinney at vbforums
Dim ctl As Control = Me.GetNextControl(Me, True)
Do Until ctl Is Nothing
allControls.Add(ctl)
ctl = Me.GetNextControl(ctl, True)
Loop
'now return the controls you want
Return allControls.OrderBy(Function(c) c.Name). _
Where( _
Function(c) (c.GetType.ToString.ToLower.Contains(typeOfControl.ToLower) AndAlso _
c.Name.Contains("Box")) _
).ToArray()
End Function