My combobox that has 2 item. This box has a selecteindexchange event. How do I get this event to fire off again if the user chooses the same item the second time around?
This seems to work in your case
Private Sub ComboBox1_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles ComboBox1.SelectionChangeCommitted
End Sub
At this point the ComboBox doesn't have a selected text so use ComboBox1.SelectedItem which is populated at this point.
Related
I've just starting using ListView control in VS2019.
I'm sure there's a simple solution, but I can't figure out how to set the focus on the control like I can with most other controls.
I want the ListView to be focused when the form loads, and then I want to programmatically focus an item in the ListView.
I know how to focus a particular item using ListView1.FocusedItem.Index, but I can't focus the actual control.
I have tried both ListView1.Select() and ListView1.Focus() but these seem to do nothing.
What am I missing!?
Thanks
EDIT
As pointed out below, the control is actually focused using ListView1.Select() it's just not focused in the same way I'd expect, for example, a ListBox to be focused - ie, with a particular item in the list highlighted.
How would you best focus the ListView and highlight a particular item?
I have tried this in a command button on the form, but it doesn't do anything. Though it works correctly AFTER I click an Item in the ListView.
ListView1.Select()
If (ListView1.SelectedItems.Count > 0) Then
ListView1.Items(4).Selected = True
End If
listview1.focus()
For I as Integer = 0 to ListView1.Items.Count - 1
If ListView1.Items(i).Text = "youritemtexthere" then
ListView1.Items(i).Selected = true
End If
End For
or if you have the index but not a known text just do:
listview1.focus()
ListView1.Items(index).Selected = true
ListView1.Select works, you probably just don't see that the ListView has focus. You can verify this by checking the GotFocus and LostFocus events on the ListView:
Private Sub ListView1_GotFocus(sender As Object, e As EventArgs) Handles ListView1.GotFocus
Me.Text = "Got Focus"
End Sub
Private Sub ListView1_LostFocus(sender As Object, e As EventArgs) Handles ListView1.LostFocus
Me.Text = "Lost Focus"
End Sub
This simply updates your Form's title to "Got Focus" or "Lost Focus". You can force the focus in your Form Load event:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
ListView1.Items.Add("a")
ListView1.Items.Add("b")
ListView1.Items.Add("c")
ListView1.Select()
End Sub
I have a group box with multiple Checkboxes(food item) and each one has a corresponding NumericUpDown control(quantity). For context, it is for a project based on a restaurant menu. I want to hide a button called btnSave whenever either a checkbox is unchecked or the quantity (NumericUpDown) is changed. I currently have btnSave.Hide under the CheckBox1_CheckedChanged and NumericUpDown1_CheckedChanged SubProcedures but I want to know if there's a way to do this when anything within this group box is changed instead of putting the code under each SubProcedure. Thanks
I think you meant .ValueChanged for the NumericUpDown control. (There is no .CheckedChanged) Although this doesn't matter much in this case, this is a good pattern for future reference. Instead of calling an event call a Sub from your events.
When you have several controls responding to a single Event handler, you can find out which control triggered the event by checking the sender parameter. Since, as you can see, sender is an Object you will have to cast it to the appropriate type to get the properties of a CheckBox.
Private Sub HideSaveButton()
btnSave.Hide
End Sub
Private Sub CheckBoxInGroupBox_CheckedChanged(sender As Object, e As EventArgs) Handles CheckBox1.CheckedChanged, CheckBox2.CheckedChanged
HideSaveButton()
Dim WhichCheckBox As CheckBox = DirectCast(sender, CheckBox)
Select Case WhichCheckBox.Name
Case "CheckBox1"
MessageBox.Show("CheckBox1 has changed")
Case "CheckBox2"
MessageBox.Show("CheckBox2 has changed")
End Select
End Sub
Private Sub NumericUpDown1_ValueChanged(sender As Object, e As EventArgs) Handles NumericUpDown1.ValueChanged
HideSaveButton()
End Sub
I have an application where I have around 50 labels. In those labels a number is visible.
When the user clicks on the label the number needs to be written to an edit box.
This works fine, the only problem is that I have added 50 functions like below, and every time it’s the same. I was wondering if there is a common function for this
Remark: The labels have different names. So if its possible that this will work for all the labels on the form.
Private Sub LI_L_Click(sender As Object, e As EventArgs) Handles LI_L.Click
cmbOBJID.Text = LI_L.Text
End Sub
In the form designer, you should be able to set the handler for every label to the same function. Then you can use the "sender" parameter to determine which label is raising the event.
Notice also how all the controls that the function is linked to are listed after the "Handles" keyword. This is another way you could connect the code to all the labels if you prefer this over using the Visual Studio UI properties grid.
Private Sub LI_Click(sender As Object, e As EventArgs) Handles Label1.Click, Label2.Click, Label3.Click
cmdOBJID.Text = DirectCast(sender, Label).Text
End Sub
While it is easy to add several events to one handler in the style of
Private Sub LI_Click(sender As Object, e As EventArgs) Handles Label1.Click, Label2.Click, Label3.Click
It will be tedious for more than just a few labels.
You can add handlers programatically if you can find a way to refer to the labels you need to add handlers to. In this example, I put all the labels in a groupbox named "GroupBoxOptions":
Option Infer On
Option Strict On
Public Class Form1
Sub TransferDataToEditBox(sender As Object, e As EventArgs)
Dim lbl = DirectCast(sender, Label)
tbEditThis.Text = lbl.Text
End Sub
Sub InitLabelHandlers()
For Each lbl In GroupBoxOptions.Controls.OfType(Of Label)
AddHandler lbl.Click, AddressOf TransferDataToEditBox
Next
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
InitLabelHandlers()
End Sub
End Class
You may have some other way of selecting the labels which use the handler.
A pretty nice and quick solution is to traverse all the label controls on a form, assigning through the AddHandler function the event to run when a user clicks a label.
In code:
For Each c As Control In Me.Controls.OfType(Of Label)
AddHandler c.Click, AddressOf myLabelClick
Next
With the prevous snippet, we loop onto all the winform controls of type Label. A loop like that is useful when we have a lot of labels for which an event must be assigned. For each of them, we associate the event Click of the control with a customized Sub named myLabelClick. That subroutine will look like the following:
Private Sub myLabelClick(sender As Object, e As EventArgs)
cmdObjId.Text = DirectCast(sender, Label).Text
End Sub
Here we use the sender variable (which represents the control for which the click has been done) to access its Text property, and change the cmdObjId.Text accordingly.
Just to complement the solution from BlueMonkMN:
If you are using the DevExpress Tools, you need to import DevExpress.XtraEditors and change Label to LabelControl:
DirectCast(sender, LabelControl).Text
This worked for me.
I have about 50 radiobuttons on one form and I don't want to create an if statement for each one to detect when one changes, they are not part of a group box. How would I detect if any radiobutton changed and then write the name to another variable?
Put all the radio buttons on a panel and loop through the panels radio button controls, programmatically adding the same event handler for each as described by #Steve. One way I like to handle the event is to assign each radio button an index into its tag property. Then just store any relevant data in a list of objects and access the data for that radio button by pulling out it's corresponding object from the list using its tag. Much easier than doing it by hand.
Edit: Good catch #Neolisk. Updated answer.
You could Always set the CheckedChanged event for all 50 radiobuttons to the same event handler.
This is an example done via code:
Private Sub OnChange(sender As System.Object, e As System.EventArgs)
Dim rb = CType(sender, RadioButton)
Console.WriteLine(rb.Name + " " + rb.Checked.ToString)
End Sub
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
AddHandler Me.RadioButton1.CheckedChanged, AddressOf OnChange
AddHandler Me.RadioButton2.CheckedChanged, AddressOf OnChange
' and so on .....'
End Sub
I have done this via code and not using the designer to avoid the long add of Handles RadioButton1.CheckedChanged, RadioButton2.CheckedChanged .......
I can't seem to get input focus on a textbox when a tab page first comes up (I'm using Windows Forms, VB.NET 3.5).
I have a textbox on a panel on a tab page, and I want the focus to be on the textbox when the tab page comes up. I want the user to be able to start typing immediately in the focused textbox without having to click on the textbox. I have tab stops set in the order I want and the textbox is the first tab stop. The tab stops work except that when the tab page comes up the focus is not on the textbox, i.e. the one that's first in the tab order.
In the Enter event handler of the tab page I call the Focus method of the text box, but it returns False and does nothing, no error messages. I know I can access the text box because
at the same point in the code I can set the text of the text box.
If it matters, the layout of the tab page is a little complicated:
frmFoo/TabControl1/TabPageX/Panel1/Panel2/TextBox1
I want to set the focus on TextBox1.
What's the best way to get the focus on the desired textbox?
If setting focus is the best way, why is the textbox.Focus() method failing?
I would assume you are attempting to set focus in the form load event handler? If so, you need to do a Me.Show() to actually create the onscreen controls before focus can be set. Something along the lines of:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs)
Me.Show()
Application.DoEvents()
TextBox1.Focus()
End Sub
If you don't do the Me.Show(), the form is NOT displayed until the load event is complete.
For the tab control, handle the _SelectedIndexChanged event:
Private Sub TabControl1_SelectedIndexChanged(sender As Object, e As System.EventArgs) _
Handles TabControl1.SelectedIndexChanged
If TabControl1.SelectedTab.Name = "TabPage1" Then
TextBox2.Focus()
End If
If TabControl1.SelectedTab.Name = "TabPage2" Then
TextBox4.Focus()
End If
You will still want to set the initial focus in the load event as shown above if the first field selected is to be the textbox on the tab control.
Try either:
Me.ActiveControl = TextBox1
or
TextBox1.Select()
Do the control.Focus() in the OnShown event. You don't need any of the DoEvents logic which didn't work for me anyway.
You Should Use Selected Event of TabControl
Private Sub TabControl1_Selected(ByVal sender As Object, ByVal e As System.Windows.Forms.TabControlEventArgs) Handles TabControl1.Selected
If e.TabPage.Name = "TabPage1" Then
TextBox1.Select()
End If
End Sub
As I have Checked in Both TabControl.Selected and TabPage.Enter Event can set Select TextBox. I think there is some other elements stealing focus. please varify
Any of the solutions I found online don't solve the problem when the control is on a tab page.
However, this works:
(1) set the TabIndex of the control to 0.
(2) In your code that handles the tabpage event, do the following:
SendKeys.Send("{TAB}")
If SendKeys doesn't seem to be a valid statment, make sure you have the following import at the top of your code file:
Imports System.Windows.Forms
I found that the TabControl gets the focus when the Selected event completes. To make this work I used the Paint event of the TabPage to set the focus of the desired object.
Private Sub TabChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Tab1.Paint, Tab2.Paint, Tab3.Paint
Select Case sender.Name
Case "Tab1"
Textbox1.Focus()
Case "Tab2"
T3extbox2.Focus()
Case "Tab3"
Textbox3.Focus()
End Select
End Sub
Try the Activated event of the form like this:
Private Sub Form2_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Activated
'SendKeys.Send("{TAB}") this line works too
TextBox1.Focus()
End Sub
That is guaranteed to work.
I once had the same problem but i solved it using the Me.activate() function.