VB.net chosing serial port System.IO.IOException - vb.net

I am trying to edit open source code i found, there is allot of bugs there, anyway i solve everything but i still have this one:
i put a combo drop-down menu to chose between serial ports to communicate with arduino, but it seems always the program chose COM5 if i chose other port or not.
this is the error i have when i press start button to communicate
An unhandled exception of type 'System.IO.IOException' occurred in System.dll
Additional information: The port 'COM5' does not exist.
and this is the combo drop-down menu code
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs)
Handles ComboBox1.SelectedIndexChanged
End Sub
and this code for the start button
Private Sub Button7_Click(sender As System.Object, e As System.EventArgs)
Handles Button7.Click
SerialPort1.Open()
SerialPort1.Write("~")
SerialPort1.Write("LCD is working!")
Timer2.Start()
SerialPort1.Close()
End Sub


but it seems always the program chose COM5 if i chose other port or not. this is the error i have when i press start button to communicate
This code
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
End Sub
is intended to get the combo box index selected by a user and set which serial port they selected. However, the body of that handler is empty, so it is not actually doing anything.
The code
Private Sub Button7_Click(sender As System.Object, e As System.EventArgs) Handles Button7.Click
SerialPort1.Open()
is presumably where the Exception is being thrown. You have not changed the settings of SerialPort1 anywhere in the code you show. Presumably, you should add some code to ComboBox1_SelectedIndexChanged to update the properties of SerialPort1 to reflect the COM port the user selected.

Related

getting problems with Me.close

so im trying to make it that when you click an image, it will close the current form. but I'm getting this error.
Property access must assign to the property or use its value.
and here's the code
Private Sub PictureBox4_Click(sender As System.Object, e As System.EventArgs) Handles close.Click, close.Click
Me.close()
form1.Show()
End Sub
that's everything. thanks!

the handles event gets problem. remove close.click,close.clic and Copy the PictureBox1.Click after Handles in your click function
Private Sub PictureBox1_Click(sender As Object, e As EventArgs) Handles PictureBox1.Click

Visual Basic - Wait for webpage to load not working

I'm trying to load a website, wait for it to fully load and then display a message box when it's loaded.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
WebBrowser1.Navigate("https://www.google.com")
Do Until WebBrowser1.ReadyState = 4
Threading.Thread.Sleep(100)
Loop
MsgBox("Loaded")
End Sub
However, when I use this nothing happens, at all despite waiting about 30 seconds. If I remove everything to leave me with...
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
WebBrowser1.Navigate("https://www.google.com")
End Sub
..., It loads fine.

The UI isn't going to load the page because you've tied up the UI thread in an infinite (or at least near infinite) loop.
Instead of waiting for the browser to load, asynchronously respond to the event of the browser loading. Something like this:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
WebBrowser1.Navigate("https://www.google.com")
End Sub
Private Sub WebBrowser1_DocumentCompleted(ByVal sender As Object, ByVal e As WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
MsgBox("Loaded")
End Sub
Any time you find yourself wanting to "pause" an application to wait for something to happen, it's highly likely that you need to subscribe to an event when that something happens.

If I'm seeing this right, its due to the fact you're making the main thread stop everytime you're running the check. Couldn't you just add an event handler on the DocumentCompleted event?

Trying to enter a name in a textbox, hit ok, and have that form close and pass the info to another forms label

***THE CODE FROM THE FIRST WINDOW GOES INTO A TEXT BOX AND YOU HIT THE BUTTON HERE.
Private Sub btnOk_Click(sender As Object, e As EventArgs) Handles btnOk.Click
Me.Close()
End Sub
***THE CODE ON THE FORM WHERE I WANT THE INFO TO BE PLACED IS HERE.
Private Sub Loan1Form_Load(sender As Object, e As EventArgs) Handles Me.Load
Me.lblCompanyName.Text = DataEntryForm.txtCompanyNameInput.Text
End Sub
Anyway's that's what I found on a youtube video and im having trouble getting it to work. Any help would be appreciated.
Thanks.

Pass the data to an instance of the form:
Private Sub btnOk_Click(sender As Object, e As EventArgs) Handles btnOk.Click
Dim f As New OtherForm
f.lblCompanyName.Text = txtCompanyNameInput.Text
f.Show()
Me.Close() 'make sure this form is not the one that closes the app if it closes
End Sub

Windows Forms: Keeping Check Beside Checked Box list item and displaying separate message for each

When I run my program currently, Within any checked box list I am unable to actually select an option (i.e. the box beside it, to tick).
I would also like each individual option to display a messagebox when ticked (i.e. "User story one added"), But currently my program only displays a general messagebox ("User Story selected") once the checked box list is clicked on. Any help would be much appreciated!
Current Code:
Public Class Form2
Private Sub CheckedListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles CheckedListBox1.SelectedIndexChanged
MessageBox.Show("User Story Selected")
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Form3.Show()
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Me.Hide()
Form1.Show()
End Sub
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
End Sub
End Class

You are responding to the wrong event and might be likely to examine the wrong property.
Private Sub CheckedListBox1_ItemCheck(ByVal sender As Object, _
ByVal e As System.Windows.Forms.ItemCheckEventArgs)
MessageBox.Show("User Story Selected")
End Sub
Checks fire the ItemCheck event, and checked items are in the CheckedItems Collection. The SelectedItems collection is literally those selected (highlighted) which might not also be checked. It is not really a list of checkboxes, but a list of items drawn as checks - thats why they look different than regular checks. To see which item:
For n as Integer = 0 to CheckedListBox1.CheckedItems.Count-1
userWants = CheckedListBox1.CheckedItems(n)
Next n
Like a ListBox you can put anything in there, not just strings, so it was a list of stories, you might be able to do:
userWants = CheckedListBox1.CheckedItems(n).StoryName

VB.net opening and closing forms

I have a VB program that has two forms, i have coded the form load of each forms.
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
MessageBox.Show("I AM FORM 1")
End Sub
Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
MessageBox.Show("I AM FORM 2")
End Sub
Here is how i switch through Form1 and Form2, i made use of a button.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Hide()
Form1.Show()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Hide()
Form2.Show()
End Sub
But everytime i switch forms the form load event will only trigger once. Is there something wrong with my code? I am guesing the Me.Hide() will only hide the previous form and not totally close it. I want to be able to close the previous form so that when i will open it again, the form load event will trigger again.

But everytime i switch forms the form load event will only trigger once. Is there something wrong with my code? I am guesing the Me.Hide() will only hide the previous form and not totally close it.
This is exactly what is happening. The Hide method just hides the form from the user, effectively making it invisible.
What you're looking for is the Close method, which actually closes the form. (Since you are displaying the form using the Show method, you do not need to call Dispose.)
You will, however, not be able to close a form and continue to run code in its methods. So you'll need to reverse the order of the statements in your event handler functions, displaying the other form first and then closing itself. Make them look like this:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Form1.Show()
Me.Close()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Form2.Show()
Me.Close()
End Sub
That will do what you want. The Load event will be triggered each time you call the Show method, because you're creating and showing a new form.
It is worth pointing out, though, that you're relying on an unusual characteristic of VB.NET, one that it retains from the older VB languages for backwards compatibility reasons. Instead of referring to an object of your form class (like you would have to do with all other class objects), you are referring to it by the type name (the name of the class itself). You really shouldn't do that, it causes all sorts of headaches and will confuse people reading your code. It is better to just instantiate a new form object, like this:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim frm As New Form1 ' create a new Form1 object
frm.Show() ' ... and display it
Me.Close()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim frm As New Form1 ' create a new Form2 object
frm.Show() ' ... and display it
Me.Close()
End Sub
When you run this code, you will likely run immediately into another problem: the first time you close Form1, your entire application will quit. This is because, by default for a new project, Form1 is designated as the "Startup form" in your project's properties ("My Project" in the Solution Explorer). You will either have to:
create a third form to use as the "main" form, and set the "Startup form" to this third form, or
change the "Shutdown mode" (also in "My Project") from "When startup form closes" to "When last form closes".

I am guesing the Me.Hide() will only hide the previous form and not totally close it
Yes, it does what it says. If you want to close the form then use Me.Close() instead. The Load event will fire again when you create the new instance.
You'll have to change a setting to ensure that doesn't also close your application. Project + Properties, Application tab, change the Shutdown mode setting to "When last form closes". And put the Me.Close() call after the Show() call.

I also had a similar question. When u .Hide() you are just storing it away in memory somewhere such that when it is re-opened it doesnt have to make a new form just recalls the one from memory hence that method is not called again. You have to destroy the form. So what you can do when navigating to another form is go to that form first and then destroy the current form like so Form2.Show()Me.Close(). Look at my question and my accepted answer. If that works please dont forget to tick this as your accepted answer.
When my form is hidden and reloaded from another form it is not executing the code in the Load event

If MessageBox.Show("Are you sure to close this application?", "Close",
MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
frmIndex.Show() //the main form
Else
e.Cancel = True
Me.Show() // The form open
End If
The form open going closing and going back to the main/index form. hope it help :) just play with the .show, .hide and e.cancel

I think you using a silly construction, but you should;
Private Sub Form2_Shown(sender As Object, e As EventArgs) Handles Me.Shown
Form1.close()
End Sub
Use the Shown event.
And use ShowDialog()
Form1.ShowDialog()

Yes. What you are doing is closing the form before it could open up form2.
Instead Of:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Hide()
Form1.Show()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.Hide()
Form2.Show()
End Sub
You Need To Put:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Form1.show
Me.hide
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Form2.show
Me.hide
End Sub
If This Helps, Please Reply.