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Hi,
I am trying to implement a site(Read/Update/Delete operations site) using MVP pattern. Also trying to keep the presentation layer UI agnostic(i.e. Presentation layer should work with a Web Client/Windows Client).
Now I have a domain object with around 30 fields/attributes and all of these fields are editable in the UI(View).
I want to propogate the change in any field to the Presentation layer. The only solution I can think of is to define 30 events!!! in the View and 30 handlers in the Presentation layer or define 30 setter methods in the presentation layer for the 30 event handlers in the view.
Am not comfortable with this design.
Can any one provide me a solution or a direction on this?
Regards,
Cybernate
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First, why should the presentation layer work in two different presentation models?
You mean the controller?
I can see this:
Model <shared>
Controller <shared>
View - one instance for web, one instance for web form
That makes more sense to me.
I'm also assuming your changes are to "something" not just random fields, but fields that belong to an object.
So why not maintain the original object state in the controller:
Controller<T> where T: class
T _state;
Have a typed args, something like:
public class TypedArgs<T> : EventArgs where T: class
{
public T Value { get; set; }
}
Create an interface for your views:
public interface IView<T> where T: class
{
event EventHandler<TypedArgs<T>> Changed;
}
then you can raise Changed with the new entity in the view, and have the controller register. Just pass in IView to the controller so it doesn't care if it's a user control or a web form, and when Changed is raised, it can compare e.Value to the stored state and decide what to do.
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Thanks Jeremy.
I tried to provide my question with an example.
I have a scenario where I have to display a view with around 30 fields(some are textboxes and some are Dropdowns) and the Business Object to represent the entity would be something like:
[CODE]
Parent
{
PField1
PField2
.
.
.
.
PField19
PField20
List<Son> Sons;
List<Daughters> Daughters;
}
Son
{
SField1
SField2
SField3
}
Daughter
{
DField1
DField2
DField3
DField4
DField5
}
[/CODE]
Am capturing/displaying the whole business entity in a single view.
Now the user can change the base fields of a parent or change the fields of a son/daughter.
Now how should I handle the change events for each field in the view, should I delegate the change events to the Presenter and then let presenter update the view. This requires to define 22 events in the View and then 22 delegate events in view and 22 event handlers in the presentation layer.
Somehow am not having a good feeling about this design.
Can you please advise?
Regards,
Cybernate
modified on Tuesday, July 28, 2009 4:01 PM
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AFAIK, MVP is not well suited for web-applications. It works well with stand-alone applications. You may try the MVC model. ASP.NET has a MVC framework available. Give it a try.
Cybernate wrote: I want to propogate the change in any field to the Presentation layer. The only solution I can think of is to define 30 events!!! in the View and 30 handlers in the Presentation layer or define 30 setter methods in the presentation layer for the 30 event handlers in the view.
That is ugly. You can have only one method in the presentation layer which takes an aggregate data structure and does the UI binding. Read this[^] MSDN article which takes MVP pattern in detail.
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Thanks for your inputs.
I am not sure if I agree with you on MVP not suited for Web Apps.
Regarding the 30 Events statement I was being sarcastic.
Thanks for trying though.
Regards,
Cybernate
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hi guys...
i want to make a user availability control in a ajax enabled asp.net website
so i placed a textbox & a label(which shows the username exists or not ) inside the updatepanel
i use a button(placed outside updatepanel) as a trigger for asynchronous postback of the updatepanel
all works fine ...but the page is reloaded.....i mean the user have to wait a few seconds for the output...
but i want it asynchronously ...so the total page is not updated...
help me .....
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Make sure that the Updatepanel updatemode is "Conditional" and set your textbox autopostback to "true"
Vuyiswa Maseko,
Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/
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i have done this all....
but still the pasge is reloaded....invisible for a little time & then shows the output
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can i see the markup
Vuyiswa Maseko,
Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/
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pls i was running an application ,when i clicked on a radio button,it threw a java script error "object expected and i need it resolved
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jude mgbaka wrote: when i clicked on a radio button,it threw a java script error "object expected and i need it resolved
It means object is not found. Please show us the code.
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We cant know until we see the code
Vuyiswa Maseko,
Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/
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Are you calling any javascript function on radiobutton click.Check that are you able to get all the controls object properly?
Cheers!!
Brij
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I think the javascript function that you are calling doesnt exists which is fired when Radiobutton is clicked.
Or it must be thrown from the javascript function itself. 
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Seriously, if you think we can help based on this, you probably are so far out of your depth that you should give up on your current project and try to learn some basics first. We can't possibly fix your code if we can't see it.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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I am used to work with datagrid, now I am wondering whether or not datalist has paging option?
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Hi,
How to Customize my Gridview? As per my requirement i want to show blank line in gridview, which will differ the two sets of data.
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You did not explain clearly what you want, let me give you another chance, please try again and explain clearly
Vuyiswa Maseko,
Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/
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I want to display data in the gridview. After 2 records displayed i want to display the blank row, which will separate another set of rows. So please let me know the solution.
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That wont be a good idea in a gridview, use another control not gridview it was not meant for that.
Vuyiswa Maseko,
Few companies that installed computers to reduce the employment of clerks have realized their expectations.... They now need more and more expensive clerks even though they call them "Developers" or "Programmers."
C#/VB.NET/ASP.NET/SQL7/2000/2005/2008
http://www.vuyiswamaseko.somee.com
http://www.vuyiswamaseko.tiyaneProperties.co.za
vuyiswa@its.co.za
http://www.itsabacus.co.za/itsabacus/
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srikantha_nagaraj wrote: How to Customize my Gridview? As per my requirement i want to show blank line in gridview, which will differ the two sets of data.
I will suggest you either use Repeater Control For that or Use XSLT for customize display 
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How to use XSLT. Can u give me the example with sample code please.
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Do you want to have blank line between the rows?
Cheers!!
Brij
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