I'm not sure if the question properly asks what I want, because I'm a bit new, but what I am trying to do is write a sub or function that I can run when a label is clicked, and I want to to be reusable on multiple labels. There will be 12 in total, and I don't wish to write the same thing over and over, with slightly different characters. A programmer never wants to write the same thing twice, right? Also, something else is making it a necessity to do it dynamically.
So, how I was trying to accomplish that was by using a string, and adding the name of the label to the string on click.
click1 = "Label1"
As it turns out, you can't just say click1.Text and return the text of Label1. The reason it's important to do it implicitly is because I need to somehow remember the one I clicked before, to compare the first click and second click, and if they match, do A, and if they don't match, do B.
The first parameter (it is called sender) to the event handler your wrote to respond to the click event is the object which sent the event.
If you assign the same routine to respond to on click of all your labels, it will be called for every one of them, but the sender parameter will point to the actual label which was clicked
HTH
mfeingold is correct, if you're unsure of the syntax:
Private Sub LabelClicked (ByVal sender As Object, ByVal e As EventArgs) Handles Label1.Click, Label2.Click, Label3.Click
sender.Text = "I've been clicked."
End Sub
Related
I have the following code:
Private Sub btnNew_Click(sender As Object, e As EventArgs) Handles btnNew.Click
Dim f As New frmStyle
f.ShowDialog()
End Sub
frmStyle does many things during it's Load event, so it doesn't appear immediately. Instead, it takes around 1 second to show up.
Because of that, I want to show an hourglass cursor during the form's Load event.
In VB6 it was super easy. I could just use "Screen.Cursor = vbHourglass".
Then you could set the cursor back to the default from whereever you wanted, for example at the end of a Form_Load event.
How can this be done in VB.NET now?
I want to show the cursor application-wide, and not for a single control only.
And ALSO (what makes my question unique and NOT answered so far in another question), I need to reset it, but it should be reset at the end of Form_Load (which is NOT the initializing element. Instead the button is the "initializing" element, but I can not set the cursor to default at the end of the button click because ShowDialog is shown modally. This means that the cursor would only be changed back if the form was closed again).
Thank you!
So I have a form with a variety of different controls (combobox, textboxes, listboxes, etc).
My first thought is to create a If, Else, End If statement. Well while that would work, it could also get pretty long, depending on the amount of controls and combinations.
Validation could include if a listbox is filled, checkbox is checked, etc pertaining to WinForms.
Is there a better solution to check all possiblities than an If statement?
It might be worthwhile to do the error checking as the user fills out the form. This could be implemented with the LostFocus event. Ex:
Private Sub btnTest_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles yourbutton.LostFocus
Dim txt = yourbutton.Text
If txt = "yourtest" Then
'do stuff
EndIf
End Sub
As above. It depends on the Validation you are trying to do. Are you validating user input, datatype lenght range, etc. Are you validating business rules. Should such and such a value equal something else. There's all kinds of possibilities.
okay... How do I explain this without being totally confusing?... Alright, I have this form that has MenuScripts (top-levels and second-levels). The problem that I am having is one of the second-levels is "Add" which brings you to another form when clicked. This other form has a button ("Record") and text boxes. This other form allows the user to input data and when the record button is clicked, the inputted data is written into a text file. Ok, so back to the first form. Another second-level MenuScript is "Update" which also brings the user to the other form; but first, the user has to click an item within a listbox to proceed. How do I get the data from the selected item to appear in the appropriate textboxes and how do I get the record button to update data instead of being confused and thinking it is only a add-data button?
Is there a way to use an "if" statement to say something like "if mnuAdd is clicked then" "elseif mnuUpdate is clicked then". Would something like that work for giving the record button multiple uses?
Also, if someone can give me some pointers on making sure the user selects an item within the listbox would definitely be a plus! Thanks, guys!
Unfortunately, I cannot add images since my reputation is too low.
Here is a visual representation of my ultimate goal
Easiest way: before displaying the second form set it's Tag property to something distinct – say "Add" or "Update" – depending on which menu item is selected. Then you just test the Tag value in the button's Click event and proceed accordingly.
As for determining whether a list item is selected: well if there isn't the ListBox's SelectedIndex property will be set to -1.
You need to put a public property on the second form (Details) which specifies which mode it is in. For instance, you could create a mode enumeration like this:
Public Enum EntryModes
AddBook
UpdateBook
End Enum
Then, define a public mode property on the second form, like this:
Public Property EntryMode As EntryModes
Get
Return _entryMode
End Get
Set(ByVal value As EntryMode)
_entryMode = value
End Set
End Property
Private _entryMode As EntryMode
Then, when you show the second form from the menu, just set the property first, before showing it:
Private Sub mnuAdd_Click(sender As Object, e As EventArgs)
Dim dialog As New DetailsDialog()
dialog.EntryMode = EntryModes.AddBook
dialog.ShowDialog()
End Sub
Private Sub mnuUpdate_Click(sender As Object, e As EventArgs)
Dim dialog As New DetailsDialog()
dialog.EntryMode = EntryModes.UpdateBook
dialog.BookToUpdate = ListBox1.SelectedItem
dialog.ShowDialog()
End Sub
As you can see, in the Upate menu click, I also added a line that passes the information for which book should be updated.
I have a program that replaces every letter of the alphabet with something new inside the same textbox by clicking a button then buy clicking the button it translates it back to original text.
However when i run this program, yes it does work as needed but not 100%
Because after i click the button to translate, (yes it shows translated)
If delete the translated text and type something new, it goes back to the old text.
(this does not happen if i click the button again, it shows the orignal text. But if i type something new it will translate it.)
Any suggestions?
This is a continuation of your other question. You will need to reset your Boolean variable when you type in your TextBox i.e.
Private Sub TextBox1_KeyPress(sender As Object, e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
bConverted = False
End Sub
How can I refer to the control while I am inside a control's method in VB.NET?
For example, I want in a textbox to show a message box with that textbox's text every time the text changes. The code would be something like:
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
msgbox("The text is:"+ Me.text)
' ok the line above wont work i already know that, because "Me" refer to the form,
' not the control textbox1
' how i will refer to the textbox1's text???
' i dont want to use "textbox1.text" is there a way similar like the "Me" is for forms?
' because i want to copy-paste a code like this in a lot of controls and do not want to
' have to change in every copy the name to each control name
End Sub
I hope I made myself clear; my English needs some improvement :D
No, there's no keyword that allows you to do that. However, every event raised by a control passes in a sender parameter that you can use to determine which particular control raised that event.
Note that this parameter is always typed as a basic Object (because it can represent any possible control), so you'll need to downcast to a more specific control class if you need to access any of the unique members that it exposes. Since you're handling an event raised by a TextBox control, you know that the sender must be of type TextBox, so you can simply use DirectCast to handle the upcasting. You don't have to worry that an InvalidCastException will be thrown.
For instance, your above example would become:
Private Sub TextBox1_TextChanged(ByVal sender As Object, ByVal e As EventArgs) Handles TextBox1.TextChanged
Dim textBox As TextBox = DirectCast(sender, TextBox)
MessageBox.Show("The text is: " & textBox.Text)
End Sub
That being said, there are a couple of concerning things that jump out at me in your question:
Any time that your approach to solving a problem is "copy-pasting" code, you should stop, take a step back, and try to figure out if there's any better way to achieve your ultimate goal.
For example, if you need every textbox on your form to react in the same way whenever a particular event is raised, you should consider subclassing the existing TextBox control and consolidating all of your code in one place. Remember that you can inherit off of most of the standard controls to add custom functionality. This is often a far better solution than copying and pasting code to multiple places in your project. If you ever need to track down a bug or modify that functionality, you'll only have to change it one place in your code, rather than several. As a somewhat cheekier benefit, you'll be able to use Me to refer to that control when you're editing its subclass.
You should always prefer to concatenate (combine) strings using the & operator in VB.NET, rather than the + sign. Or perhaps even better, the String.Concat or String.Format methods.
There is no reason to use MsgBox in VB.NET, as opposed to MessageBox.Show. No, this won't improve performance of your application, but it's a good practice to get into for .NET languages.
The sender variable contains the TextBox instance you want to access. You only need to convert the sender to TextBox.