I had searched a lot how to display a Msgbox that will not wait the user input (pressing ok or cancel).
I found 3 solutiuons to this.
1- Display the MsgBox() in another thread or using BackgroundWorker()
2- Create a form that display the message, then closed the form by a timer and use it instead of Msgbox()
3- Using the API MessageBoxA()
Let say I have a loop from 1 to 100, and I want display a message for the i(counter)
When I test above 3 ways, I found that this is not the right way of doing it, I don't need a msgbox() to close by it self after showing the message, because that will display 100 dialog.
What I realy want is to display ONLY 1 MsgBox() and change the text accordingly.
I managed to do this using a a Form() as class and I did it using Application.DoEvents
I know it can be done using BackgroundWorker or Threading since alot of people advice against using Application.Doevents
Here is my code
Dim oWW As New WaitWindow With {.TopLevel = True,.TopMost = True,.StartPosition = FormStartPosition.CenterScreen}
oWW.Show(Me)
For i = 1 to 100
Threading.Thread.Sleep(500) ' Just to slowdown execution
oWW.SetMessage("Counter = " + i.ToString)
Next
oWW.Dispose()
Public Class WaitWindow
Sub SetMessage(ByVal Message As string)
lbl_message.Text = Message
Application.DoEvents
End Sub
End Class
WaitWindow is not more than a Form base class with a label (lbl_message)
That code works fine (display WaitWindowForm on center of currently displayed form only once, then I change the text)
I have 3 questions :
1- How to display the WaitWindowForm in the top right corner of my working form?
2- Is it possible to display the normal MsgBox() or MessageBox.Show() only once, then capture the text displayed and change it?
3- Which one is suitable for my issue (BackGroundWorker or Threading) and what the code in WaitWindow class I post will be if I decided to use Backgroundworker or Threading instead of Application.DoEvents (Changing the label text not showing new form with new text) ?
3 questions in one post.. humm.. who cares, I am not the one who will answer lol :)
Thanks in advance.
I think the issue that you're really encountering is that you're trying to use a message box for something it's not suited for. If you want to have text that constantly changes just add a text box in the upper right corner of your application and adjust it every time a new message needs to be shown.
You can also look up dialogu windows (search ".showdialog() vb.net" in google) might help as well.
Related
I have a problem with the snippet of the code I have got to extend and improve. It is not my original code and I cannot change the logic that much of it, just to be clear.
I have one main form called MDIServer, which has a timer set for every second. In Timer.Tick I have some other code which works fine (timer is running okay). Newly, I had to check there, if one form is Active and if so, change some stuff (labels text and tags) in that form and refresh it.
I add there this code:
If IsActiveForm("frmName") Then
frmName.ChangeSomething()
End If
The Sub ChangeSomething is, how you can see, located in the form I want to refresh and do the changes. In that function I simply change the label text and tags of few controls.
My question is: Form is not refreshing => labels are not visible changed, why?
I think I tried already almost anything with Refresh() function in the ChangeSomething() function or in the timer after I called this function. Also I tried to add there new timer (in frmName) and do the changes there, which works perfectly with
Label.Text = "something new"
Label.Refresh()
So I guess problem is somewhere with the refreshing form from Timer in different form. I also tried to do it with my own InvokeReguired() function etc...
P.S. When I am debugging the code, labels and tags are changing and every single function which has to be called, is called, but it is just not visible on the form itself.
EDIT Info
formName is not declared in MDIServer explicitely and in this case and many other cases, forms are used as default instances. Timer is from System.Windows.Forms.Timer. Also MDIServer is not a MDIParent of the formName and I cannot use Me.ActiveMdiChild Is. Lets just say, these two forms are not dependent on each other in any way.. and everything is done through name of the form (default instance, so nothing like Dim frm As Form and frm = frmName).
I would be really glad for any tip or anything :D
Thanks guys,
Vojta
So, I fixed my problem after some research and the problem was (expected) that I am not calling the subroutine ChangeSOmething() for one specific instance of the form frmName. So I had to change my code, that I will call it exactly for the instance which is active and visible.
New code looks like this:
Dim frmCollection = Windows.Forms.Application.OpenForms
Dim listfrmname = frmCollection.OfType(Of frmName).ToList()
If listfrmName.Count > 0 Then
Dim tmpFrm As frmName = listVZT15.Last()
tmpFrm.ChangeSomething()
End If
I also could not use combination of frmCollection.OfType(Of frmName).Any and frmCollection.Item("frmName"), because when I was closing the form and opening again, it created new and new instances (I dont know, why it is not closing the old one, but like I said, it is not my code). So the logic is, to list all open forms of the needed type, and then take the last instance from that list and for that instance call the subroutine. Also Me.Refresh() is placed in the subroutine ChangeSomething() itself.
Thanks everyone for help, it surely helped me to understand, how the instances works here.
I'm stuck with something that I have tried to overcome before and couldn't.
Last time I worked around it, but I really need to nail this down.
I have a multi-instance form which lists details of jobs, so a user may have 6 or so instances of this form open, all with different info. Lets call that form A.
Within form A there is an option to assign that job to a user.
Clicking that link label opens a new form using showdialog where a combobox is populated with logged in users... Lets call that form B.
What I want to do is have the value selected on form B passed back to form A, however because form A has multiple instances, I'm not sure how to call it.
Form A is JobDetails.vb, and always has a form title of "Job XXXXX Details", so I was hoping there was a way I could use the title to call it.
Hope that all make sense! Thanks in advance, and apologies if its a dumb question. I feel like this should be something obvious, but I just can't achieve it.
As shown on the help page of ShowDialog, you can easily alter the main form when the dialog-form is closed. So you could do something like this:
Public Sub ShowMyDialogBox()
Dim testDialog As New Form2()
' Show testDialog as a modal dialog and determine if DialogResult = OK.
If testDialog.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK Then
Me.Text = String.Format("Jobs of {0}", testDialog.cmboUsers.SelectedValue)
Else
Me.Text = "Jobs"
End If
testDialog.Dispose()
End Sub
I would really appreciate your advice on the following:
I'm working on Windows forms using VB.NET (even though the language is irrelevant to the question at hand).
I've got a main form and wish to call out another one, however depending on a given variable I need the text on some of the new form's elements to change as well as disable some of its controls.
There are two ways I see of doing it:
Send a parameter from the main form and have some logic on the second form to deal with everything on load.
Main Form:
dim newform as new frmcalculate(byval type as string)
New Form:
public sub getexplanation(byval type as string)
select type
case "Sum"
lblexplanation.text = "this is a sum"
case "Subtraction"
lblexplanation.text = "this is a subtraction"
End sub
Set exactly what I want on the main form before calling the new form.
i.e:
dim newform as new frmcalculate()
newform.lblexplanation.text = "This is a sum"
I hope I've managed to explain it correctly.
I'm still new at this especially getting the formats right on Stackoverflow.
In the first approach the code is best managed and organized for further editing. So each form has it own code.
It is not best practice to use second approach. (Editing a form designer from another one)
I have two forms with combo boxes. The combo box values are stored in My.Settings.testDevices. (System.Collections.Specialized.String.Collection) with a scope of User.
The second form adds the ability to add items to testDevices, and then upon exit it updates My.Settings.testDevices.
Now, only if I make a change to the settings (adding items only), when I exit back to the main form (which remains loaded throughout the process), my application crashes with the following message:
"Additional information: Destination array was not long enough. Check destIndex and length, and the array's lower bounds."
As I understand it, this might be a concurrency issue, however I'm not sure.
My code:
In my main form Load event: (to load from My.Settings)
testDevicesComboBoxMain.Items.Clear()
My.Settings.testDevices.CopyTo(mainFormTestDevices, 0)
testDevicesComboBoxMain.Items.AddRange(mainFormTestDevices)
Where "testDevicesComboBoxMain" is the combo box on the main form.
On the secondary form Close Event: (to save to My.Settings)
Dim items(testDevicesComboBox.Items.Count - 1) As String
testDevicesComboBox.Items.CopyTo(items, 0)
My.Settings.testDevices.Clear()
My.Settings.testDevices.AddRange(items)
My.Settings.Save()
I have found similar questions on here, but none with answers that I understand :P
As I am a beginner with vb.net, could any answers be provided in an easy to understand form please!
Thanks.
I forgot to add:
Public items(My.Settings.testDevices.Count - 1) As String
Public mainFormTestDevices(My.Settings.testDevices.Count - 1) As String
I tried setting separate declarations just in case there was some kind of conflict. These obviously do the same thing, just with different names.
I fixed it by adding a For loop to read from My.Settings.
For Each i As String In My.Settings.testDevices
testDevicesComboBoxMain.Items.Add(i)
Next
This seems to have cured the problem, and may perhaps be a more "modern" way of doing it?
I desperately need help with a game I am making. For a bit of context, i am making a memory game and i have the following piece of code that is being troublesome. I have a bunch of labels on the form, 16 to be exact, with 1 randomly generated symbol placed in each. Each symbol appears in the labels twice.
------------------------------Continued----------------------------------------
'MsgBox("hello") 'used to check if the second inccorect press shows up - it does show but instantly changes colour
'''''''''''''''''NEED SOME CODE THAT PAUSES IT HERE'''''''''''''''
labels(0).ForeColor = Color.DarkRed
sender.ForeColor = Color.DarkRed
End If
flips = 1
End If
End If
tmrmemory.Enabled = True ' starts the timer after the user clicks the first label
End Sub
What's supposed to happen is that when the labels clicked don't match, it should show both the clicked labels for a short period before changing them both back to "DarkRed" which is the colour of the form's background.
I have tried using a timer but then i can't use sender.forecolor=color.darkred because it is not declared globally.
I have also tried using the command Threading.Thread.Sleep(500) but it still doesn't show the second incorrect click. I know that the code i have used works because when i use the message box, i can see both symbols and when the two clicks are correct, it stays.
Threading.Thread.Sleep(500) will actually pause your code for half a second. However during this time it won't do anything, not even refresh your controls. To get the effect you want, you need to call the YourControl.Refresh method before calling Threading.Thread.Sleep to force the control to redraw immediately.
On a side note, I would advise you not to call Threading.Thread.Sleep on UI thread. It will give a feeling of program hang. Instead do your work on a separate thread. You can either do all the work yourself right from creating a separate thread to destroying it, or use the BackgroundWorker control which has all the functionality built in.
Here is the link to an article I wrote a long time ago regarding BackgroundWorker that might be useful for you:
http://www.vbforums.com/showthread.php?680130-Correct-way-to-use-the-BackgroundWorker
Declare a variable outside the sub that stores what label should be flipped when the timer ends.
Label click sets
storedLabel = sender
Timer tick sets storedLabel.ForeColor = Color.DarkRed