Limit Tabs / Forms

[SBarnes]

Is there a way to limit the number of forms/tabs that a user can open in the MDI Parent?

[Scott.Pearce]

Sound like a job for a plugin.

[SBarnes]

Yeah I know that but not where to start???

[Scott.Pearce]

Code: Select all

Manager.MDIParentForm.MdiChildren

[Mike.Sheen]

Yeah I know that but not where to start???

Manager has a property, MDIParentForm and that has a property OwnedForms which is a list of Form. Use the count of that to see if you have exceeded your imposed limit in a handler of the Manager.FormFactory BeforeFormStart event.

[Scott.Pearce]

You are making it too easy for him Mike

[Mike.Sheen]

You are making it too easy for him Mike

Sorry - I didn't realise we were supposed to be making it difficult.

[SBarnes]

No if you wanted to make it difficult you would have given me the code in CIL but it's not April yet

[SBarnes]

Ah see you promised not to make it difficult and unless I've missed something I found a bug in the below code only the After Start message shows up and looking in Just Decompile in the form Factory BeforeFormStart is declared but never checked for being set and called and OwnedForms.Length is always zero.

Code: Select all

public class ApplicationManagerPlugin : System.MarshalByRefObject, JiwaFinancials.Jiwa.JiwaApplication.IJiwaApplicationManagerPlugin
{
   
    public override object InitializeLifetimeService()
    {
        // returning null here will prevent the lease manager
        // from deleting the Object.
        return null;
    }

    public void Setup(JiwaFinancials.Jiwa.JiwaApplication.Plugin.Plugin Plugin)
    {
      //System.Diagnostics.Debugger.Launch();
      Plugin.Manager.FormFactory.BeforeFormStart += BeforeFormStart;
      Plugin.Manager.FormFactory.AfterFormStart += AfterFormStart;
      
      
    }
   
   
    public void BeforeFormStart(JiwaFinancials.Jiwa.JiwaApplication.Forms.Form form, string RecordID, bool NewRecord, object OwnerForm)
   {
      
      System.Windows.Forms.MessageBox.Show("Before form start " +  form.Manager.MDIParentForm.MdiChildren.Length.ToString());
   }
   
   
   public void AfterFormStart(JiwaFinancials.Jiwa.JiwaApplication.IJiwaForm JiwaForm)
   {
        System.Windows.Forms.MessageBox.Show("After form start " +  JiwaForm.Manager.MDIParentForm.MdiChildren.Length.ToString());       
   }
}


[Mike.Sheen]

Ok, then use the property Scott suggested - Manager.MDIParentForm.MdiChildren.

I only suggested OwnedForms because in our LogOff method we use that to close all open forms - whether they are MDI Children or not:

Code: Select all

Public Sub LogOff()
   Dim cancelargs As New System.ComponentModel.CancelEventArgs
   RaiseEvent LoggingOff(cancelargs)

   If cancelargs.Cancel = False Then
      If Not MDIParentForm Is Nothing Then
         For Each form As Form In MDIParentForm.OwnedForms
            form.Close()
         Next
      End If
...