So i want to make a maze game in Visual Basic and if the cursor reaches a certain panel, it will show a message box ONCE and then the Form closes.
The question is How?
I've tried
Private Sub Panel1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Panel1.Paint
If Cursor.Position = Panel1 Then
MsgBox("Completed")
Application.Exit()
End If
End Sub
And didn't work. I got
Error 1 Overload resolution failed because no accessible '=' can be
called with these arguments:
'Public Shared Operator =(left As System.Drawing.Point, right As System.Drawing.Point) As Boolean': Value of type
'System.Windows.Forms.Panel' cannot be converted to
'System.Drawing.Point'. C:\Documents and Settings\Admin\Local
Settings\Application Data\Temporary
Projects\WindowsApplication1\Form1.vb 4 12 WindowsApplication1
Remember that i want the message box to only appear once, because sometimes when the cursor is on the panel, it shows multiple msgbox until the cursor is outta there.
I want the mouse inside the panel and run a code.
I believe there is an event called 'mouse enter' event you can use so if you type the code for the messagebox in that even for the control you want them to mouseover it will pop up everytime they do that.
For it to to nly pop up once make a counter that adds 1 and dont execute that code if the counter is already on 1.
I had a little search and found: Determine whether the mouse is over a control? (over a Control pixel range)
I just knocked up a test with a button and seemed to work fine. Please adapt to your own needs.
Private Sub Button1_Paint(sender As Object, e As PaintEventArgs) Handles Button1.Paint
Debug.WriteLine(MouseIsOverControl(Button1))
End Sub
Public Function MouseIsOverControl(ByVal c As Control) As Boolean
Return c.ClientRectangle.Contains(c.PointToClient(Control.MousePosition))
End Function
In this example I've just output "true or false" to determine detection. You can test and change it to your own needs to determine what you want to do depending on 'true/false'. Hope this helps.
Related
I have declared a Sub that is meant to trigger when the listbox 'lstStudents' is double-clicked. However, it does not trigger when this happened. There can't be an error in the code itself as it is auto-generated. Why does the code not function as expected? The code is below:
Private Sub lstStudents_DoubleClick(sender As Object, e As EventArgs) Handles lstStudents.DoubleClick
Msgbox("test")
End Sub
The message box is only present for testing purposes.
Could You try to delete that previous "lstStudents" and add new one then apply the "ListBox1_DoubleClick" on it again to make sure it works.
Otherwise let us know what is going there because I think your code is normally and it should be working 100%.
I am trying to create a sub in a module that simply hides a lot of panels for a Form which is passed as a parameter to it. Basically, Ill have a button called students and a button called subjects and I want that when I click on the, lets says, students button ALL the panels I define in the function get hidden, and only the students panel remains visible.
When I run this code I get :
System.MissingMemberException: 'Public member 'pnlAlumnos' on type 'Ventana_Principal' not found.'
Code in my module
Module Modulo_Comportamiento_Ventanas
Public Sub Esconder_todos_los_paneles(ventana As Object)
ventana.pnlAlumnos.Hide()
ventana.pnlMaterias.Hide()
End Sub
End Module
Code on the main Form click
Private Sub btnAlumnos_Click(sender As Object, e As EventArgs) Handles btnAlumnos.Click
Esconder_todos_los_paneles(Me)
Me.pnlAlumnos.Show()
End Sub
How can I modify my code in order to being able access the panels and hiding them?
Thanks in advance!
Note : BTW, I know I can do this, but I want to know why it does not work the way I am doing it, I mean the below code looks horrible ( not that my other path looks any more nicer) :
Public Sub Esconder_todos_los_paneles()
WindowsApp1.Ventana_Principal.pnlAlumnos.Hide()
WindowsApp1.Ventana_Principal.pnlMaterias.Hide()
End Sub
I am a simple beginner and need small help:
I have textbox1 and textbox2.
Supposed when you put a number (for ex. 21) in the textbox1, I need textbox2 to give me the double number (42). I mean that I need textbox2.text=2*textbox1.text
I used this simple code :
Private Sub TextBox1_Textlength(ByVal sender As System.Object, ByVal e As System.EventArgs)
Handles TextBox1.TextChanged
TextBox2.Text = 2*TextBox1.Text
The problem is: when I wrote (in textbo1) only one digit everything it's ok, but I could not write two (or more) digits.
How do I make a delay (interval) which allows me to type a number like (1990 for example) before firing textbox1_changed?
TextChanged fires every time you change the content of the textbox. So there is no way to block this behavior. Perhaps you could add a button and move the recalculation on the button click event or better add an event handler for the Validating event.
This event is triggered when you exit from the control and you have also the option to check the input and block the exiting from the TextBox control
Private Sub textBox1_Validating(ByVal sender As Object, _
ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox1.Validating
Dim v as Integer
if Not Int32.TryParse(TextBox1.Text, v) Then
e.Cancel = True
MessageBox.Show("Please type a valid number")
Else
TextBox2.Text = (v * 2).ToString
End If
End Sub
Notice that when you handle the user input expecting a numeric value you should apply particular attention because you don't know what the user types. In this case the Int32.TryParse seems to be the appropriate approach.
Another suggestion is to enable immediately the Option Strict ON in your project, the default is OFF and this allows very dangerous code like treating a string like it was a number.
You don't need to. Just allow the TextChanged event to fire every time, and the second text box will always display twice the value of the first one, so when 1 is entered, it will show 2, when the 9 is added, it will show 38, and so on. You should of course address Steve's concerns about validation, and implied type conversions.
So I've set my application to a console type application and pointed it to a module containing just Sub Main, i.e.
Module mdlConsole
Sub Main(ByVal cmdArgs() As String)
If cmdArgs.Length = 0 Then
Dim frm As New frmMain
frm.Show()
End If
End Sub
End Module
Ideally if no arguments are supplied then the program would simply launch the primary form. The goal is to make this program (optionally) script-able from the command line. If arguments are supplied then the application form is not loaded and processes its features based off the command line arguments supplied.
As it is now, the program runs, briefly launches the form (frmMain) and then closes. What am I doing wrong or missing?
If you're not keen on giving me the answer, I'd be happy to be pointed in the right direction also. I don't expect anyone to just supply answers. I need to learn also.
Thanks!
For Winforms, you need to 'run' the App object, passing a form to use:
Sub Main(ByVal cmdArgs() As String)
If cmdArgs.Length = 0 Then
Dim frm As New frmMain
Application.Run(frm)
Else
' cmd line version
End If
End Sub
I see in your comment that you'd like to remove the console window that appears when running the form version of the program with the solution currently proposed. I cannot comment due to lack of reputation, so I will make this a full-fledged answer.
Consider approaching this from an inverse perspective: if you write the program as a forms application, opening it by default will bring up the form. But in the Form1_Load event, check the command line arguments; if they are greater than 0, simply run your (abbreviated) code logic here. At the end of the code, simply run Application.Exit(), like so:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
If My.Application.CommandLineArgs.Count > 0 Then
' Execute (abbreviated) code logic
' When finished, exit the program
Application.Exit()
End If
End Sub
This can also make your code cleaner and more practical if you're relying on a user-interface, because you can still access the values of form elements that the user would otherwise be modifying - but without the form showing on the screen (unless you prompt it to with a MsgBox or such).
This also works very nicely for Scheduled Tasks, as the user can run them manually with a user-interface, while the program executes without being visible via a scheduled task.
Kind of a follow-on to Chad's solution above I used the steps defined in How to have an invisible start up form? to avoid showing my form.
In short, create an Overrides subroutine that gets launched before Form1_Load:
This worked for me:
Protected Overrides Sub SetVisibleCore(ByVal value As Boolean)
If Not Me.IsHandleCreated Then
Me.CreateHandle()
value = False
MyBase.SetVisibleCore(value)
Else
Exit Sub
End If
If My.Application.CommandLineArgs.Count > 0 Then
MsgBox("Argument Sensed!")
' Execute (abbreviated) code logic
' When finished, exit the program
Me.Close()
Application.Exit()
Else
MyBase.SetVisibleCore(True)
End If
End Sub
I have translated some code from C# to VB.net for the purpose of getting Folder Browser functionality. The link to the code is here.....
http://www.codeproject.com/KB/aspnet/DirectoryBrowsing.aspx
My issue is that I have not been able to correcly translate these two lines of code to VB.net.
TreeView1.TreeNodeExpanded +=new TreeNodeEventHandler(TreeView1_TreeNodeExpanded);
TreeView1.SelectedNodeChanged += new EventHandler(TreeView1_SelectedNodeChanged);
Every translator I have used has simply dropped the semicolon from the end of each line. But the editor still does not like them.
I could some help with this as it seems this effects the refresh of the selected folder in the tree view control.
I don't get to see the C drive folder unless I type the path in the text box, and the folder will still not expand.
thank you,
Use this:
AddHandler TreeView1.TreeNodeExpanded, AddressOf TreeView1_TreeNodeExpanded
AddHandler TreeView1.SelectedNodeChanged, AddressOf TreeView1_SelectedNodeChanged
Edit:
A different way to do this would be to apply it at the method level:
Protected Sub TreeView1_TreeNodeExpanded(ByVal sender as Object, ByVal e as TreeNodeEventArgs) Handles TreeView1.TreeNodeExpanded
' Some code
End Sub
Protected Sub TreeView1_SelectedNodeChanged(ByVal sender as Object, ByVal e as EventArgs) Handles TreeView1.SelectedNodeChanged
' Some code
End Sub
You should run this in debug to find out what exactly is going on. I find a lot of times when events of this nature are run in asp.net, you have a conflicting event that "resets" the controls you are attempting to change.