ShowDialog() Not Showing Modal

But wouldn't code execution stop on ShowDialog if it was modal?

You are correct, .ShowDialog() should open the form as modal.

Do you have anything on dlgDBSelect that could be closing it?

If not, i would suggest putting a breakpoint on the line when you ShowDialog() and stepping through the code.

If dlgDBSelect is part of the main project you could also use my.forms.dlgDBSelect.ShowDialog() which even if the form didnt show as modal, it would stay open after the subroutine exits

There is no code in dlgDBSelect that would close the form.  In fact, if I comment out all the code within the form, the problem remains.

I did try single-stepping through the code.  It goes into the form's load event where it loads a dropdown box on the form.  Then, when it exits the form's load event, the code returns to the calling function as if it were a non-modal form.

During code execution, there are no errors thrown.

This might sound an odd suggestion but could you try putting  Application.DoEvents() before you ShowDialog()?

I have read somewhere before regarding a similar problem and that fixed it.

Dim dlg2 As New dlgDBSelect
dlg2.DatabaseArrayList = arlDBList
Application.DoEvents() 
dlg2.ShowDialog()
                                              

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SteveR3110,

I tried adding the DoEvents as you suggest.  It does nopt work, but now I get an error when the code leaves the procedure that contains the dialog code.  The code does not stop anywhere (not even through sigle step, it throws the error right after "End Sub")

Attached is the error report given by VB.Net

System.NullReferenceException was unhandled
  Message="Object reference not set to an instance of an object."
  Source="Microsoft.VisualBasic"
  StackTrace:
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.MainFormLoadingDone(Object sender, EventArgs e)
       at System.EventHandler.Invoke(Object sender, EventArgs e)
       at System.Windows.Forms.Form.OnLoad(EventArgs e)
       at System.Windows.Forms.Form.OnCreateControl()
       at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       at System.Windows.Forms.Control.CreateControl()
       at System.Windows.Forms.Control.WmShowWindow(Message& m)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       at System.Windows.Forms.ContainerControl.WndProc(Message& m)
       at System.Windows.Forms.Form.WmShowWindow(Message& m)
       at System.Windows.Forms.Form.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       at System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       at System.Windows.Forms.Control.set_Visible(Boolean value)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at CQPricingUtil.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
                                              

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Just reading your error there, are you trying to show this new dialog form in the load event of your main form?

What happens to the main form after end sub (provided you take out the code i suggested)? Does that application exit or are you saying that it does show the second form just not modal?

Ok, here is the setup as it currently stands (I didn't write it, I'm adding some modifications).

The start up form is a "splash" form.  It's Form_Load event calls a sub procedure called "DoProc()"

DoProc() causes a login form (user name and passord) to be displayed modally.  This is old code and currently works.

There is a bit of code verifying the user then the Database selection form is to be displayed modally. (This is where I have the problem)

Once the database is selected, the splash screen is unloaded and the main form is displayed.  This has been removed for the time being, until I can get the database selection form to work.  As it currently sits, after the database selection form closes, the code exits DoProc() and then exits the splash screen's form load event which in turn exits the program.

What version VB.Net Clif?

By DEFAULT, when the "Startup Form" (the splash form in your case) closes the WHOLE app closes.  In VB.Net 2005 (or above) this can be fixed with a simple Project --> Properties change.

Click on Project --> Properties and change the "Shutdown mode" from "When startup form closes" to "When last form closes".

In VB.Net 2005, you could also use the Application.Startup() Event to execute the login verification code.  From there you can cancel the application if login fails and the main form will never be shown.
http://msdn.microsoft.com/en-us/library/t4zch4d2(VS.80).aspx

For earlier versions of VB.Net we would need to do some more "magic" to make it work...

I am using VB.Net 2005 Express.  I do have the setting for the app to stop "When last form closes"

The login code executes ok (cancel will close the app), it's past that when I'm having my problems.

I recommend doing the login verification in the Startup() event instead of the in the splash form.  See my link for more details...

Ok, I moved all the code from the splash form's load event and put it in the StartUp event as suggested.  I was wondering what happened to the "Sub Main()".  :)

At any rate, I'm sorry to say that the problem still exists.

You can still use a "Sub Main" in VB.Net 2005 (though I don't recommend it for most situations).

To use a Sub Main in VB.Net 2005 you have to UNCHECK the "Enable Application Framework" CheckBox in Project --> Properties.  Then you will be able to select Sub Main as the Startup from the DropDown.

But then you are missing all the NEW functionality of the "Application Model":
http://msdn.microsoft.com/en-us/library/w3xx6ewx.aspx

Many people don't even realize the powerful new features that are available to them because they are "hidden" via a button in Project --> Properties.  =\

Please describe the "flow" of the app...I'm sure it's just a matter of calling the right Forms in the right order from the correct places...

Fairly simple, actually:

1. Startup Event
2. Splash Screen is displayed
3. dlgLogin is displayed.  User types in name and password then clicks "Ok" which closes the form.
4. Once user enters name and password, an ArrayList  of databases available to that user is created
5.  dlgDBSelect is loaded
6. The ArrayList is passed to dlgDBSelect, which loads a drop-down combo.

Up to this point, everything works fine.  The probnlem is that the dlgDBSelect does not stay Modal.

7. User selects DB and clicks "Ok", which closes the form.
8. Main form loads and is displayed until app is exited by the user.

I have a feeling the splash screen may be getting in the way...

Can you test with this?

1. Startup Event (ALL code below thru #6 is occurring HERE in this Event)
2. dlgLogin is displayed.  User types in name and password then clicks "Ok" which closes the form.
3. Once user enters name and password, an ArrayList  of databases available to that user is created
4.  dlgDBSelect is loaded
5. The ArrayList is passed to dlgDBSelect, which loads a drop-down combo.

Up to this point, everything works fine.  The probnlem is that the dlgDBSelect does not stay Modal.

6. User selects DB and clicks "Ok", which closes the form.

7. Main form loads and is displayed until app is exited by the user.
*** The Main form is set as the "Startup Object" in Project --> Properties.  It loads ONLY because we have not cancelled the application in the Startup() Event with "e.Cancel = True".

Ok, I removed the code that loads the splash screen.

I changed the startup form to the main form (thanks for reminding me to do this).

The code still bypasses (or passes through) the ShowDialog() that would have displayed the dlgDBSelect form.

Ok then...let's see some code.  =)

Can you show us your Startup() event?

Certainly.  I trimmed out all the propietary code, and then ran it to make sure it still failed.

There is one thing that I hadn't noticed until now.  (Lord knows why I didn't see it before).  When the dlgDBSlect form flashes, the splash screen disappears.  I have no code to close it in either the splash screen itself or during the load of dlgDBSelect.  In fact I have commented out all the code in dlgDBSelect.

        Private Sub MyApplication_Startup(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            Dim dlgSplash As New GPTSplash
            With dlgSplash
                .Show()
                .lblStatus.Text = "Login attempt"
                .Refresh()
            End With
 
            'BeginProc()
            Dim dlg1 As New dlgLogin
            dlg1.ShowDialog()
 
            Dim dlg2 As New dlgDBSelect
            'dlg2.DatabaseArrayList = arlDBList
            Application.DoEvents()
            dlgSplash.lblStatus.Text = "Select Database"
            dlg2.ShowDialog() '<-- Blows right past this
            'At this point, the splash screen is closed as well.
        End Sub

                                              

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Can you try without the splash?  Let's remove as much as possible to narrow down where the failure occurs...

        Private Sub MyApplication_Startup(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            'Dim dlgSplash As New GPTSplash
            'With dlgSplash
            '    .Show()
            '    .lblStatus.Text = "Login attempt"
            '    .Refresh()
            'End With
 
            'BeginProc()
            Dim dlg1 As New dlgLogin
            dlg1.ShowDialog()
 
            Dim dlg2 As New dlgDBSelect
            'dlg2.DatabaseArrayList = arlDBList
            Application.DoEvents()
            dlgSplash.lblStatus.Text = "Select Database"
            dlg2.ShowDialog() '<-- Blows right past this
            'At this point, the splash screen is closed as well.
        End Sub

                                              

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In fact...why not narrow it down even further?

        Private Sub MyApplication_Startup(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            'BeginProc()
            Dim dlg1 As New dlgLogin
            dlg1.ShowDialog()
 
            Dim F As New Form
            F.Text = "Can you hear me now?"
            F.ShowDialog()
        End Sub

                                              

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I cut and pasted your highly trimmed code.

No Joy.

Just as it did with my code, it blows right past "F.ShowDialog()"

..and if we remove the dlgLogin code?...  =\

Did you make sure the Splash form in Project --> Properties is set to None?
Is there any code in the MAIN form that causes it to close down under certain conditions?

        Private Sub MyApplication_Startup(ByVal sender As Object, ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup
            Dim F As New Form
            F.Text = "Can you hear me now?"
            F.ShowDialog()
        End Sub

                                              

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Ok, well, that worked.  There is a window displayed with the title bar reading "Can you hear me now?"  Aftre cling the "X" box to close, the application continues on to the main form.

It doesn't solve my problem, but it worked.  I meen a login *and* the database select screens to display (in that order) before the main screen shows.  I cannot combine the two because I need to populate the database list based on the username/password.

Just out of curiosity, does the "highly trimmed" code that you gave (and failed) work for you?

Sorry

"I meen a login..."

Should read

"I need a login..."

Crap!

I decided to look at the code that closes the login screen.  There is a line:
Global.System.Windows.Forms.Application.Exit()

Not sure why it was there (or how the app worked before), but taking it out, now it seems to work.

Thanks for your help.  I wish I had more points to award you.

Lol...glad you finally found the errant line.  I just helped you narrow down which part was causing it...  =)