I've been doing some research and I can't seem to find any type of event for SelectionChanged for a regular textbox. Can anyone please help me with this. I do not want to use a RichTextBox. Thanks
Please refer to the link below:
TextBox.SelectionChanged Event - MSDN
Occurs when the text selection has changed.
'Declaration
Public Event SelectionChanged As RoutedEventHandler
By listening to the MouseUp event of the TextBox, you can roughly get a similar behavior :
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
AddHandler TextBox1.MouseUp, AddressOf TextBox1_OnMouseUp
End Sub
Private Sub TextBox1_OnMouseUp(ByVal sender As Object, ByVal e As MouseEventArgs)
Dim textBox As TextBox = DirectCast(sender, TextBox)
Dim selectedText As String = textBox.SelectedText
Console.WriteLine(selectedText)
End Sub
End Class
Result:
Edit:
Additionally, to properly react during double-clicks, you can encompass your code with the following safe-guard, it will ensure to not output false positives during the first click.
Dim isNullOrEmpty As Boolean = String.IsNullOrEmpty(selectedText)
If Not isNullOrEmpty Then
Console.WriteLine(selectedText) // your code
End If
Related
I'm hooking an arcobjects map event to a vb.net form to listen for map selection changes. This all works fine but users are reporting this error occassionally when opening the form. I can't see any pattern to reproduce the error and it seems to be random.
"COM object that has been separated from its underlying RCW cannot be used"
It originates from the form Load() method where I am hooking the event.
Can anyone help me understand what I've done wrong? I'm unhooking the map selection event in the FormClosing() event which I think is the correct approach.
Public Class MyForm
Private _activeViewEvents As IActiveViewEvents_Event
Private Sub FormLoad(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
_activeViewEvents = TryCast(pMxDoc.ActiveView.FocusMap, IActiveViewEvents_Event)
AddHandler _activeViewEvents.SelectionChanged, AddressOf SelectionChanged
End Sub
Private Sub SelectionChanged
'do something when selection is changed
End Sub
Private Sub FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
RemoveHandler _activeViewEvents.SelectionChanged, AddressOf SelectionChanged
End Sub
End Class
The approach you are taking to creating and destroying your handlers are valid. You can receive a RCW COM Exception when the map document is changed while your form is open. Since you are using the FocusMap to create the handles, when the document is changed, so is the FocusMap, which means you need to re-create your handlers for the new map document.
Ok so I think i've resolved this via use of the ActiveViewChanged event. Instead of rehooking the event on each form load or new document event, I tried listening for when the ActiveViewChanged event was fired and rehooking the SelectionChanged event each time. Turns out this is fired more than once each time a new document is opened (not sure why). Anyway, problem seems to have gone. Here's some example code:
Public Class MyForm
Private _activeViewEvents As IActiveViewEvents_Event
Private _docEvents As IDocumentEvents_Event
Private Sub FormLoad(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
AddHandler _docEvents.ActiveViewChanged, AddressOf ActiveViewChanged
End Sub
Private Sub ActiveViewChanged()
Dim maps = pMxDoc.Maps
For i = 0 to maps.Count - 1 'remove handlers from all maps
RemoveActiveViewEvents(maps.Item(i))
Next
SetupActiveViewEvent(pMxDoc.ActiveView.FocusMap) 'only add handler to active map
End Sub
Private Sub RemoveActiveViewEvents(map As IMap)
_activeViewEvents = CType(map, IActiveViewEvents_Event)
RemoveHandler _activeViewEvents.SelectionChanged, AddressOf SelectionChanged
End Sub
Private Sub SetupActiveViewEvents(map As IMap)
_activeViewEvents = CType(map, IActiveViewEvents_Event)
AddHandler _activeViewEvents.SelectionChanged, AddressOf SelectionChanged
End Sub
Private Sub SelectionChanged
'do something when selection is changed
End Sub
End Class
I want to know if it is possible in VB 2010 to changed the CheckChanged of a CheckBox when clicking the same object. For Example:
I have a 1 picturebox named pic1 and a checkbox named chck1, If I click the pic1, the chck1 must be checked but If I click again the pic1, chck1 must be unchecked and I click again the pic1, chck1 must be check again and so on..
I really don't have an idea if it is working or impossible in VB 2010, I hope someone can help me. Thank you very much.
If it's a WinForm, then you just have to implement something like this:
you have your PictureBox and your Checkbox, and you just have to add a clickhandler to your picturebox like this:
private void pictureBox1_Click(object sender, EventArgs e)
{
checkBox1.Checked = !checkBox1.Checked;
}
This Method always negates the Checked-State of the Checkbox (it's way simpler than a if/else)
checkbox1.Checked contains the checked-state, so that is how you can uncheck/check it.
Edit: i did it in c#, sorry,
in VB.NET it would be something like
Private Sub pictureBox1_Click(sender As Object, e As EventArgs)
checkBox1.Checked = Not checkBox1.Checked;
End Sub
In a WinForms application just add the event handler for the click event of your PictureBox.
You could that easily with the Form Designer or, if using code, then write
' In the form constructor
Public Sub Form1()
' First initialize your form controls'
InitializeComponent()
' then add the event handler for the picturebox click event'
AddHandler pic1.Click, AddressOf pic1_Click
End Sub
Private Sub pic1_Click(sender As Object, e As EventArgs)
' toogle the checked state of the checkbox'
chk1.Checked = Not chk1.Checked
End Sub
As said below from Mr Neolisk you could also shorten this code simply adding the Handles clause to the pic1_Click event thus removing the code in the Form constructor
Private Sub pic1_Click(sender As Object, e As EventArgs) Handles pic1.Click
' toogle the checked state of the checkbox'
chk1.Checked = Not chk1.Checked
End Sub
I'm using vb.net and winform. I am coming across an issue which I'm pounding my head against for the past few hours.
I have a main usercontrol which I added a groupbox and inside that groupbox, added a control like this:
main usercontrol
Me.GroupBox1.Controls.Add(Me.ctlWithDropDown)
user control ctlWithDropDown
Me.Controls.Add(Me.ddList)
Private Sub ddlList_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlList.SelectionChanged
'some simple logic here to check if value changed
End Sub
The main usercontrol inherits the base class which has an event to set a value to true or false like so:
Public Event SetFlag(ByVal value As Boolean)
I want to know how I can trigger/set this boolean value from the dropdownlist when the SelectionChanged event is trigger. Any help on this issue?
Wire up an event handler for the drop down list:
AddHandler Me.ctlDropDown.SelectedIndexChanged, AddressOf ddlSelectedIndexChanged
Me.GroupBox1.Controls.Add(Me.ctlDropDown)
Make sure you create ddlSelectedIndexChanged in your control and have it fire the SetFlag Event:
Protected Sub ddlSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
RaiseEvent SetFlag(True)
End Sub
I presume the me.ctlDropDown is something that you are making programmatically? If so then this sort of thing should work for you.
Public Sub Blah()
Dim ctlDropDown As New ComboBox
AddHandler ctlDropDown.SelectedIndexChanged, AddressOf IndexChangedHandler
Me.GroupBox1.Controls.Add(ctlDropDown)
End Sub
Private Sub IndexChangedHandler()
'Do whatever you need here.
End Sub
However, if this is not created at runtime should make an event handler like:
Private Sub IndexChangedHandler() Handles Me.ctlDropdown.SelectedIndexChanged
'Do whatever you need here.
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.
When using flash, I was able to get to the focus of an event by accessing the event's "target" attribute.
so if I remember, it was something similar to.
button1.addEventListener(mouse_click, doSomething);
doSomething(e: Event){
e.target.size = 50000;
}
And I'm looking for the equivalent in VB.
If you can give me it's common name across all languages, I'd be doubly grateful. I don't quite know what to search for aside from "event.target VB.net equivalent, and that's not returning anything.
Thanks in advance.
edit: for those new to flash. By focus, I mean the physical object that was clicked on. So the example given would be accessing the clicked button's size.
In VB you can wire up event handlers declaratively using the WithEvents keyword or imperatively using AddHandler.
Private WithEvents myButton
' OR
Public Sub New
Dim newButton = New Button()
AddHandler newButton.Click, AddressOf MyClickHandler
End New
'To consume it you declare a method as follows:
' The Handles clause is used when declaring WithEvents
Private Sub MyClickHandler(sender As Object, e As EventArgs) Handles myButton.Click
' The sender has a handle on the object that raised the event (aka the button)
Dim btn = DirectCast(sender, Button)
btn.Size = New Size(500, 500)
End Sub
Got it!
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.button.onclick.aspx#Y0
Sub GreetingBtn_Click(ByVal sender As Object, ByVal e As EventArgs)
'When the button is clicked,
'change the button text, and disable it.
Dim clickedButton As Button = sender
clickedButton.Text = "...button clicked..."
clickedButton.Enabled = False
End Sub
The first parameter (sender by default) references the focused object. You can access it as you would any other normal variable, but it's information won't appear in the auto complete list unless you set it "As" that specific data type.
So I ended up with this
Private Sub nw_btn_Click(ByVal sender As System.Windows.Forms.Button, ByVal e AsSystem.EventArgs) Handles nw_btn.Click
sender.Hide()
End Sub