|
ms
newsgroups
|
|||||||||||||||||||||||
|
|||||||||||||||||||||||
How to Verify if EventHandler for ValueChanged has been set?controls, like TextBox, NumericUpDown, ComboBox, etc. I want each one to have its ValueChanged (or TextChanged) event handler set, like: ----------- System.Windows.Forms.TextBox cityTextBox; cityTextBox = new TextBox(); cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); ----------- I can loop through all of the controls of the application starting with this.Controls and, recursively their children, finding everyone of my 100 individual controls. I want my software to verify if I have every TextChanged or ValueChanged event handler set. Any clues? Thanks Richard,
You would have to use reflection for this, as you don't have access to the event handler list from outside the instance that exposes the event. You would have to look for the backing field for the delegate, but the thing is, there is no guaranteed linking between that field and the event exposed. For the standard event implementation (no add/remove handlers), it should work, but you might run into some custom add/remove handlers and it won't be that easy to figure out what the backing field for the event is. Are you doing this for unit testing, or within your app? If you are doing it within your app, I would recommend making this a unit test or maybe a custom rule for FxCop. -- Show quoteHide quote- Nicholas Paldino [.NET/C# MVP] - mvp@spam.guard.caspershouse.com <richard.mart***@raymondjames.com> wrote in message news:6b0427f8-3b02-406a-af2f-b8145011866f@v18g2000vbb.googlegroups.com... >I have a huge Windows desktop application with over 100 individual > controls, like TextBox, NumericUpDown, ComboBox, etc. > > I want each one to have its ValueChanged (or TextChanged) event > handler set, like: > > ----------- > > System.Windows.Forms.TextBox cityTextBox; > > cityTextBox = new TextBox(); > cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); > > ----------- > > I can loop through all of the controls of the application starting > with this.Controls and, recursively their children, finding everyone > of my 100 individual controls. > > I want my software to verify if I have every TextChanged or > ValueChanged event handler set. > > Any clues? > > Thanks > > On Dec 16, 1:12 pm, "Nicholas Paldino [.NET/C# MVP]"
<m...@spam.guard.caspershouse.com> wrote: Show quoteHide quote > Richard, Nicholas:> > You would have to use reflection for this, as you don't have access to > the event handler list from outside the instance that exposes the event. > > You would have to look for the backing field for the delegate, but the > thing is, there is no guaranteed linking between that field and the event > exposed. For the standard event implementation (no add/remove handlers), it > should work, but you might run into some custom add/remove handlers and it > won't be that easy to figure out what the backing field for the event is. > > Are you doing this for unit testing, or within your app? If you are > doing it within your app, I would recommend making this a unit test or maybe > a custom rule for FxCop. > > -- > - Nicholas Paldino [.NET/C# MVP] > - m...@spam.guard.caspershouse.com > > <richard.mart***@raymondjames.com> wrote in message > > news:6b0427f8-3b02-406a-af2f-b8145011866f@v18g2000vbb.googlegroups.com... > > > > >I have a huge Windows desktop application with over 100 individual > > controls, like TextBox, NumericUpDown, ComboBox, etc. > > > I want each one to have its ValueChanged (or TextChanged) event > > handler set, like: > > > ----------- > > > System.Windows.Forms.TextBox cityTextBox; > > > cityTextBox = new TextBox(); > > cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); > > > ----------- > > > I can loop through all of the controls of the application starting > > with this.Controls and, recursively their children, finding everyone > > of my 100 individual controls. > > > I want my software to verify if I have every TextChanged or > > ValueChanged event handler set. > > > Any clues? > > > Thanks- Hide quoted text - > > - Show quoted text - Yes, I have tried reflection as follows: ---------- using System.Reflection; System.Type type = cityTextBox.GetType(); EventInfo eventInfo = type.GetEvent("TextChanged", BindingFlags.Instance | BindingFlags.Public); MethodInfo methodInfo = eventInfo.GetRaiseMethod(true); // // However, methodInfo always comes back null. // ---------- Is the above code what you had in mind? Richard,
From the remarks of the documentation for GetRaiseMethod: This method returns a null reference (Nothing in Visual Basic) for events declared with the C# event keyword or the Visual Basic Event keyword. This is because the C# and Visual Basic compilers do not generate such a method. Because there is no guarantee about how the delegate chain is stored for the event (basically, it's like a property, you don't know what is being used to store what is returned to you when you call the property), there is really no way to get that list for inspection with certainty. -- - Nicholas Paldino [.NET/C# MVP] - mvp@spam.guard.caspershouse.com <richard.mart***@raymondjames.com> wrote in message news:6b9b3795-ad42-4460-b598-17582f09dbd2@k1g2000prb.googlegroups.com... On Dec 16, 1:12 pm, "Nicholas Paldino [.NET/C# MVP]"<m...@spam.guard.caspershouse.com> wrote: Show quoteHide quote > Richard, Nicholas:> > You would have to use reflection for this, as you don't have access to > the event handler list from outside the instance that exposes the event. > > You would have to look for the backing field for the delegate, but the > thing is, there is no guaranteed linking between that field and the event > exposed. For the standard event implementation (no add/remove handlers), > it > should work, but you might run into some custom add/remove handlers and it > won't be that easy to figure out what the backing field for the event is. > > Are you doing this for unit testing, or within your app? If you are > doing it within your app, I would recommend making this a unit test or > maybe > a custom rule for FxCop. > > -- > - Nicholas Paldino [.NET/C# MVP] > - m...@spam.guard.caspershouse.com > > <richard.mart***@raymondjames.com> wrote in message > > news:6b0427f8-3b02-406a-af2f-b8145011866f@v18g2000vbb.googlegroups.com... > > > > >I have a huge Windows desktop application with over 100 individual > > controls, like TextBox, NumericUpDown, ComboBox, etc. > > > I want each one to have its ValueChanged (or TextChanged) event > > handler set, like: > > > ----------- > > > System.Windows.Forms.TextBox cityTextBox; > > > cityTextBox = new TextBox(); > > cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); > > > ----------- > > > I can loop through all of the controls of the application starting > > with this.Controls and, recursively their children, finding everyone > > of my 100 individual controls. > > > I want my software to verify if I have every TextChanged or > > ValueChanged event handler set. > > > Any clues? > > > Thanks- Hide quoted text - > > - Show quoted text - Yes, I have tried reflection as follows: ---------- using System.Reflection; System.Type type = cityTextBox.GetType(); EventInfo eventInfo = type.GetEvent("TextChanged", BindingFlags.Instance | BindingFlags.Public); MethodInfo methodInfo = eventInfo.GetRaiseMethod(true); // // However, methodInfo always comes back null. // ---------- Is the above code what you had in mind? If you still going to use reflection, you can use something like that:
private bool AreListenersAdded(TextBox control, string eventName) { var controlType = control.GetType(); var fields = controlType.GetFields(BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.Instance); var eventField = fields.SingleOrDefault(f => f.Name == "Event" + eventName); if (eventField != null) { var eventsProperty = (typeof(Control)).GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic); var events = eventsProperty.GetValue(control, null) as EventHandlerList; if (events != null) { var textChangedEvent = eventField.GetValue(control); var eventDelegate = events[textChangedEvent]; if (eventDelegate != null) return eventDelegate.GetInvocationList().Length > 0; } } return false; } <richard.mart***@raymondjames.com> wrote in message Show quoteHide quote news:6b9b3795-ad42-4460-b598-17582f09dbd2@k1g2000prb.googlegroups.com... > On Dec 16, 1:12 pm, "Nicholas Paldino [.NET/C# MVP]" > <m...@spam.guard.caspershouse.com> wrote: >> Richard, >> >> You would have to use reflection for this, as you don't have access >> to >> the event handler list from outside the instance that exposes the event. >> >> You would have to look for the backing field for the delegate, but >> the >> thing is, there is no guaranteed linking between that field and the event >> exposed. For the standard event implementation (no add/remove handlers), >> it >> should work, but you might run into some custom add/remove handlers and >> it >> won't be that easy to figure out what the backing field for the event is. >> >> Are you doing this for unit testing, or within your app? If you are >> doing it within your app, I would recommend making this a unit test or >> maybe >> a custom rule for FxCop. >> >> -- >> - Nicholas Paldino [.NET/C# MVP] >> - m...@spam.guard.caspershouse.com >> >> <richard.mart***@raymondjames.com> wrote in message >> >> news:6b0427f8-3b02-406a-af2f-b8145011866f@v18g2000vbb.googlegroups.com... >> >> >> >> >I have a huge Windows desktop application with over 100 individual >> > controls, like TextBox, NumericUpDown, ComboBox, etc. >> >> > I want each one to have its ValueChanged (or TextChanged) event >> > handler set, like: >> >> > ----------- >> >> > System.Windows.Forms.TextBox cityTextBox; >> >> > cityTextBox = new TextBox(); >> > cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); >> >> > ----------- >> >> > I can loop through all of the controls of the application starting >> > with this.Controls and, recursively their children, finding everyone >> > of my 100 individual controls. >> >> > I want my software to verify if I have every TextChanged or >> > ValueChanged event handler set. >> >> > Any clues? >> >> > Thanks- Hide quoted text - >> >> - Show quoted text - > > Nicholas: > > Yes, I have tried reflection as follows: > > ---------- > > using System.Reflection; > > System.Type type = cityTextBox.GetType(); > > EventInfo eventInfo = type.GetEvent("TextChanged", > BindingFlags.Instance | BindingFlags.Public); > > MethodInfo methodInfo = eventInfo.GetRaiseMethod(true); > > // > // However, methodInfo always comes back null. > // > ---------- > > Is the above code what you had in mind? Richard
Did you solve this? Rhino has an event raiser that works well with interfaces only. It's hard to believe that somebody doesn't have some sort of relection based tool you could use to verify an event is wired or better yet, invoke it in a unit test. I haven't found it yet though so wondering if you did. Thanks, Berryl Show quoteHide quote "Nicholas Paldino [.NET/C# MVP]" <mvp@spam.guard.caspershouse.com> wrote in message news:e3tezn6XJHA.4380@TK2MSFTNGP06.phx.gbl... > Richard, > > You would have to use reflection for this, as you don't have access to > the event handler list from outside the instance that exposes the event. > > You would have to look for the backing field for the delegate, but the > thing is, there is no guaranteed linking between that field and the event > exposed. For the standard event implementation (no add/remove handlers), > it should work, but you might run into some custom add/remove handlers and > it won't be that easy to figure out what the backing field for the event > is. > > Are you doing this for unit testing, or within your app? If you are > doing it within your app, I would recommend making this a unit test or > maybe a custom rule for FxCop. > > -- > - Nicholas Paldino [.NET/C# MVP] > - mvp@spam.guard.caspershouse.com > > <richard.mart***@raymondjames.com> wrote in message > news:6b0427f8-3b02-406a-af2f-b8145011866f@v18g2000vbb.googlegroups.com... >>I have a huge Windows desktop application with over 100 individual >> controls, like TextBox, NumericUpDown, ComboBox, etc. >> >> I want each one to have its ValueChanged (or TextChanged) event >> handler set, like: >> >> ----------- >> >> System.Windows.Forms.TextBox cityTextBox; >> >> cityTextBox = new TextBox(); >> cityTextBox.TextChanged += new EventHandler(cityTextBox_TextChanged); >> >> ----------- >> >> I can loop through all of the controls of the application starting >> with this.Controls and, recursively their children, finding everyone >> of my 100 individual controls. >> >> I want my software to verify if I have every TextChanged or >> ValueChanged event handler set. >> >> Any clues? >> >> Thanks >> >> > > Berryl:
No, I have not solved this. I have this belief (from starting in assembler 30 years ago) that a software engineer can write any software to do anything. Somehow the C# language is lacking an EventInfo.GetValue() method, like PropertyInfo.GetValue() and FieldInfo.GetValue(). The suggestion that yuriy***@hotmail.com proposed seems to be written in a language other than C#, and I could not port it over to C# because some of the methods that he calls are not in C#. I prefer to have my own software check for this rather than rely on an external tool. My overall goal is to verify that every user facing control has a ValueChanged (or TextChanged) event handler defined. For the time being, I will settle for my eyeballs and a good testing department. Show quoteHide quote On Dec 16, 5:28 pm, "Berryl Hesh" <efing***@yahoo.com> wrote: > Richard > > Did you solve this? > > Rhino has an event raiser that works well with interfaces only. It's hard to > believe that somebody doesn't have some sort of relection based tool you > could use to verify an event is wired or better yet, invoke it in a unit > test. I haven't found it yet though so wondering if you did. > > Thanks, > Berryl > > "Nicholas Paldino [.NET/C# MVP]" <m...@spam.guard.caspershouse.com> wrote in > messagenews:e3tezn6XJHA.4***@TK2MSFTNGP06.phx.gbl... > > You could always do something like this, I suppose you know:
New Modified class =========== public event EventHandler ValueChanged; public bool ValueChangedIsWired() { return ValueChanged!= null; } Test class =========== foreach(var newClass in newClassCollection) { if(!newClass.ValueChangedIsWired) // throw exception, shoot somebody, etc. } I wonder why C# doesn't havesome EventInfo class though. The you could do what you want without breaking encapsulation. Good luck with it - BH <richard.mart***@raymondjames.com> wrote in message news:4e423cc4-3d9c-452c-b3f7-c687bb0e41c8@w1g2000prk.googlegroups.com... No, I have not solved this.Berryl: I have this belief (from starting in assembler 30 years ago) that a software engineer can write any software to do anything. Somehow the C# language is lacking an EventInfo.GetValue() method, like PropertyInfo.GetValue() and FieldInfo.GetValue(). The suggestion that yuriy***@hotmail.com proposed seems to be written in a language other than C#, and I could not port it over to C# because some of the methods that he calls are not in C#. I prefer to have my own software check for this rather than rely on an external tool. My overall goal is to verify that every user facing control has a ValueChanged (or TextChanged) event handler defined. For the time being, I will settle for my eyeballs and a good testing department. Show quoteHide quote On Dec 16, 5:28 pm, "Berryl Hesh" <efing***@yahoo.com> wrote: > Richard > > Did you solve this? > > Rhino has an event raiser that works well with interfaces only. It's hard > to > believe that somebody doesn't have some sort of relection based tool you > could use to verify an event is wired or better yet, invoke it in a unit > test. I haven't found it yet though so wondering if you did. > > Thanks, > Berryl > > "Nicholas Paldino [.NET/C# MVP]" <m...@spam.guard.caspershouse.com> wrote > in > messagenews:e3tezn6XJHA.4***@TK2MSFTNGP06.phx.gbl... > >  
Other interesting topics
Procedure xxx expects parameter '@ID' which was not supplied
How to reference in c# script? Perplexed on logging both text and binary information to a file Am i calling the database twice? Linq Style Cross Platform encryption/decryption SQLException - message property was empty delegate defined by .NET Repository and Services Passing nullable string |
|||||||||||||||||||||||
