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How to add postback function in Custom Server Controls

 
 
ton
Guest
Posts: n/a
 
      02-02-2004
what i want is that when the event of the button fires I would like to show
a complete other card, not the 10 fields i've showen earlier but because of
the click i would see details depending on the click this could be 5 fields
from another record and another table. So existing added controls away, new
controls inplace

ton
"Alessandro Zifiglio" <(E-Mail Removed)> schreef in
bericht news:27tTb.2569$(E-Mail Removed)...
> still not clear to me. Instead of defining a scenario can you simplify it
> and explain it in terms of custom control building what is not working for
> you. Is your requirement to build a databound custom server control ? Are
> you looking into building a custom control that has similar functionality

to
> the datagrid, datalist, repeater and so on --what have you been able to
> implement so far. Which parts are working and where are you stuck.
>
> "ton" <(E-Mail Removed)> wrote in message
> news:bvlkqi$v3s$(E-Mail Removed)1.nb.home.nl...
> > suppose you want to plan an activity. You get a card wich contains

several
> > field like
> > date, begintime, end time, description, customer, type of activity and

so
> > on
> > type of activity is a dropdonlist
> > description a textbox
> > and the customer fields points to a foreignkey with the customer-table

(if
> > it is filled in I just show the customer name)
> > off cause i cannot use a drop down list because there will be hunderds

or
> > thoussends of customers in the database
> > so when it is empty i can press a button to select one from a list (get

e
> > search screen and then look up)
> > or i can add a new customer, in both situations I want to have a

different
> > from as the replacement of my original activity:
> > - pick from a list will show me several search fields from the table
> > customer inclusive a Search button
> > - the add new customer will give me a recordcard with the important

fields
> > to define a new customer
> > when the customer is add, or when the customer is selected from the list

I
> > replace this card by the original content where the customer field shows

> the
> > name of the customer
> >
> > So instead of multiple screens i just use the same screens to collect

the
> > information to plan this activity
> >
> > i hope you can help
> >
> >
> > Ton
> >
> >
> >
> > "Alessandro Zifiglio" <(E-Mail Removed)> schreef

in
> > bericht news:HOrTb.2542$(E-Mail Removed)...
> > > ton, Can you explain that again. Its not very clear what you want to

do
> > ;P
> > >
> > >
> > > "ton" <(E-Mail Removed)> wrote in message
> > > news:bvl8va$khs$(E-Mail Removed)1.nb.home.nl...
> > > > thank you
> > > > the event is fired now but what I had in my does not occur:
> > > > What I do is the following:
> > > > - I show a record contains of 10 fields. The properties are:
> > > > Tablename, RecordID, ShowFields (just a list of the fields to show)
> > > > now pressing a button should replace the existing recordcard by

> another
> > > > record card. For example a record contains a Contact. One of the

field
> > is
> > > > the (database)-link to the Customer. To click on that buttonlink,

> should
> > > > replace the form with for example 10 fields of the customer. You can

> say
> > > it
> > > > is a zoom function to the toplevel of the database.
> > > > For me this is inportant because it let me navigate in the database.
> > > > Another example:
> > > > when I want to modify the link I want to replace the control with a

> > search
> > > > screen to show a list of customers, where the user can select one.

Or
> to
> > > add
> > > > a complete knew one.
> > > >
> > > > The question is: "Is this possible". I do not want the webdesigner

to
> > add
> > > > several controls on the form or to add several forms to the project

to
> > > > handle these evenst.
> > > >
> > > > Ton
> > > >
> > > >
> > > > "Alessandro Zifiglio" <(E-Mail Removed)>

schreef
> > in
> > > > bericht newsZpSb.1500$(E-Mail Removed)...
> > > > > oops, no workaround. That InamingContainer Interface had me a

little
> > > > > confused ;P
> > > > > Since this interface already makes control ids unique you just

need
> > to
> > > > pass
> > > > > your id as is like
> > > > >
> > > > > button1.id = "button1"
> > > > > textbox1.id = "textbox1"
> > > > > and so forth.
> > > > > When trying to reference textbox1 for example just simply use its

id
> > > > > "Alessandro Zifiglio" <(E-Mail Removed)>

wrote
> > in
> > > > > message news:cmpSb.1494$(E-Mail Removed)...
> > > > > > ton, Look at the post "No events are fired in child controls".

> > Jeffery
> > > > has
> > > > > > just pointed out how useful Implementing the InamingContainer
> > > interface
> > > > > > really is, especially when you need events in child controls

> routed.
> > > > This
> > > > > is
> > > > > > why your events werent firing.
> > > > > >
> > > > > > Iimplement this interface, and do not try passing an explicit id

> to
> > > your
> > > > > > control if you dont need it.
> > > > > >
> > > > > > At the moment i myself am having problems passing an explict id

to
> > > child
> > > > > > controls and i'm working on a workaround. Will postback when I

do
> > find
> > > a
> > > > > > way. One good reason to want to pass an explicit id is when

using
> a
> > > > > > validator control and as you already know you need to pass your
> > > controls
> > > > > id
> > > > > > to its "controlToValidate" property.
> > > > > >
> > > > > > If this is not your case then i dont see why it is important to

> pass
> > > an
> > > > > > explicit ID
> > > > > >
> > > > > > "Alessandro Zifiglio" <(E-Mail Removed)>

> wrote
> > > in
> > > > > > message news:ZeeSb.1334$(E-Mail Removed)...
> > > > > > > Should fire. It works for me. However i have noticed that you

> are
> > > > trying
> > > > > > to
> > > > > > > add controls in your button click. This will not work for you
> > > because
> > > > > > during
> > > > > > > postback those controls wont be recreated. so set a flag in
> > > viewstate
> > > > as
> > > > > > you
> > > > > > > add the control.
> > > > > > > Also I have noticed that you are trying to retrieve the same

> > button,
> > > > the
> > > > > > one
> > > > > > > that fired the event in its event click and add it to the

> controls
> > > > > > > collection. This is not what what you need to do, but simply

> have
> > > the
> > > > > same
> > > > > > > code run after postback. Whatever code you have in your
> > > > > > createchildcontrols
> > > > > > > method will run after postback, so let it all run as is and

> remove
> > > the
> > > > > > > ispostback check in there --If that code is not run your event

> > will
> > > > > never
> > > > > > > fire, this is because the viewstate of the control is

restored
> > when
> > > > the
> > > > > > > control is reloaded into its container.
> > > > > > >
> > > > > > > Private Sub ButtonClick(ByVal sender As Object, ByVal e As
> > > > > > System.EventArgs)
> > > > > > > Dim MyButton As New Button()
> > > > > > > MyButton = CType(sender, Button)
> > > > > > > context.response.write("Click event for " & MyButton.id &

> "Fired")
> > > > > > > End Sub
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >

> >

>

http://samples.gotdotnet.com/quickst...=/quickstart/a
> >

>

spplus/samples/webforms/ctrlauth/composition/Composition2.src&file=VB\Compos
> > ition2.vb&font=3
> > > > > > >
> > > > > > > This is another example :
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >

> >

>

http://samples.gotdotnet.com/quickst...=/quickstart/a
> >

>

spplus/samples/webforms/ctrlauth/composition/Composition3.src&file=VB\Compos
> > ition3.vb&font=3
> > > > > > >
> > > > > > >
> > > > > > > "ton" <(E-Mail Removed)> wrote in message
> > > > > > > news:bvboj3$gbo$(E-Mail Removed)1.nb.home.nl...
> > > > > > > > Thanks for you reply
> > > > > > > >
> > > > > > > > I've used the code you've send me. It did not work. I made

my
> > > > control
> > > > > a
> > > > > > > lot
> > > > > > > > simpeler and the result was the same.
> > > > > > > > It looked as if the button click event were not handled by

te
> > > > > procedure
> > > > > > of
> > > > > > > > the addresoff statement:
> > > > > > > >
> > > > > > > > The code looks now like: (And I'm sure that the
> > > createchildcontrols
> > > > is
> > > > > > > > called instaed of the the buttonclick procedure)
> > > > > > > >
> > > > > > > > Protected Overrides Sub CreateChildControls()
> > > > > > > > If Me.Page.IsPostBack Then ' this is what runs after the

> button
> > > > click
> > > > > > > > ''Exit Sub '' (if I use Exit sub, no control is displayed)
> > > > > > > >
> > > > > > > > End If
> > > > > > > >
> > > > > > > > But = New Button
> > > > > > > >
> > > > > > > > But.Text = "Submit"
> > > > > > > >
> > > > > > > > But.ID = ClientID & "X"
> > > > > > > >
> > > > > > > > Controls.Add(But)
> > > > > > > >
> > > > > > > > AddHandler But.Click, AddressOf Me.ButtonClick
> > > > > > > >
> > > > > > > > ChildControlsCreated = True
> > > > > > > >
> > > > > > > > end Sub
> > > > > > > >
> > > > > > > > Private Sub ButtonClick(ByVal sender As Object, ByVal e As
> > > > > > > System.EventArgs)
> > > > > > > >
> > > > > > > > But = FindControl(ClientID & "X")
> > > > > > > >
> > > > > > > > But.Text = "xxxx"
> > > > > > > >
> > > > > > > > Controls.Add(But)
> > > > > > > >
> > > > > > > > End Sub
> > > > > > > >
> > > > > > > > I've dimensioned the button But as a private control, did

not
> > help
> > > > > > > > íve done this with the withevents keyword, no difference
> > > > > > > > and i've dimensioned them in the procedures

createchildrecords
> > and
> > > > > > > > buttonclick
> > > > > > > >
> > > > > > > > no differences
> > > > > > > >
> > > > > > > > Ton
> > > > > > > >
> > > > > > > > "Alessandro Zifiglio"

<(E-Mail Removed)>
> > > > schreef
> > > > > > in
> > > > > > > > bericht news:9DbSb.1271$(E-Mail Removed)...
> > > > > > > > > ton,
> > > > > > > > > what do you want to do with the caputred event ?
> > > > > > > > > If all you need to do is capture it and take action in

your
> > > > control
> > > > > > > itself
> > > > > > > > > then you can easily do this :
> > > > > > > > > 1.In createchildcontrols as you add your control that

posts
> > > back,
> > > > a
> > > > > > > button
> > > > > > > > > control for example :
> > > > > > > > > Dim button1 As New Button()
> > > > > > > > > button1.Text = "Submit"
> > > > > > > > > Controls.Add(button1)
> > > > > > > > > 'Notice the event handler defined below
> > > > > > > > > AddHandler button1.Click, AddressOf

> Me.ButtonClicked
> > > > > > > > >
> > > > > > > > > now define the buttonclicked sub in your control and take

> > action
> > > > > > there,
> > > > > > > > > everytime the button is clicked this will fire :
> > > > > > > > > Private Sub ButtonClicked(sender As [Object], e As

> EventArgs)
> > > > > > > > > 'What to do when button is clicked
> > > > > > > > > End Sub
> > > > > > > > > Should work for you, however I havent tested, but

> theorically
> > > this
> > > > > is
> > > > > > > all
> > > > > > > > > you need if this is your requirement. This is useful if

you
> > need
> > > > to
> > > > > > take
> > > > > > > > > action without exposing the event to the container page,

> > giving
> > > > the
> > > > > > > > > consumers of your control no control, as this event is not
> > > exposed
> > > > > to
> > > > > > > > them.
> > > > > > > > >
> > > > > > > > > for a complete example that digs deeper into this you

might
> > want
> > > > to
> > > > > > look
> > > > > > > > at
> > > > > > > > > the following link :
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >

> >

>

http://msdn.microsoft.com/library/de...us/cpguide/htm
> > l/cpconcompositecontrolsample.asp
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Instead if you need to expose this event to the page where

> > your
> > > > > > control
> > > > > > > > > sits, and exposed to the end users of your control then

you
> > will
> > > > > need
> > > > > > to
> > > > > > > > > bubble it up .
> > > > > > > > > Here is a very nice example of how this can be done for
> > > composite
> > > > > > > controls
> > > > > > > > > on MSDN.
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >

> >

>

http://msdn.microsoft.com/library/de...us/cpguide/htm
> > l/cpconeventbubblingcontrolsample.asp
> > > > > > > > >
> > > > > > > > > "ton" <(E-Mail Removed)> wrote in message
> > > > > > > > > news:bvav9a$pjr$(E-Mail Removed)1.nb.home.nl...
> > > > > > > > > > In the procedure CreateChildControls I add several

> controls
> > > like
> > > > > > check
> > > > > > > > and
> > > > > > > > > > textboxes, button link and so on. How can I get the

> postback
> > > > > respons
> > > > > > > on
> > > > > > > > > the
> > > > > > > > > > button link:
> > > > > > > > > > The functions:
> > > > > > > > > > lblButtonLink_Command and lblButtonLink_Click will not

be
> > > > executed
> > > > > > > > > >
> > > > > > > > > > Please help
> > > > > > > > > >
> > > > > > > > > > Ton
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >

> >
> >

>
>



 
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Arthur Mnev
Guest
Posts: n/a
 
      02-02-2004
My experience to you:

1. You control must implement INamingContainer to create its own namespace
for event routing
2. you override CreateChildControl and construct them according to your
rules. It might be tricky you must remember that

Even though ASP.NET supports events it is still disconnected architecture
therefore once a server sends you a page it completely forgets about you
therefore, when you click on a button (or generate other event) what must
happen is:
1 - data sent to the server
2 - server constructs control tree (it MUST construct the same control
tree as you had when you outputted the controls /previous state)
3 - It checks which control supposed to receive an event (__EVENTTARGET
post variable contains the control name)
4 - An event is raised on behalf of control
5 - You capture the event

3. Clear the control list (Controls.Clear())
4. Load Conditions (or Cache) of your previous request (ViewState could be
used to store them)
5. Build Controls based on previous conditions (or cache) - by the time you
get out of the CreateChildControls() your ChildControlsCreated flag will be
set to true by the framework
6. Event delegate will get executed
7. Make sure your event handler alters the Control Condition and calls
(this.ChildControlsCreated = false). what that will do is place an
indication flag that controls have not been created, that will case the
framework to re-run CreateChildControls;
8. When CreateChildControls re-runs it Clears it's previous control list,
loads up Build Conditions and Generates the controls. Except the build
conditions are based now on your different Build conditions.


It is like you will be running the page twice - once to build an old state,
figure out what event to raise and raise that event. Once raised you will
re-run everything to determine second state and alter your presentation.

If that is not enough think about this. When an event is mapped to the
hierarchy, the hierarchy must be in the same exact order as it has been
before, otherwise an event will get mapped to the wrong control. This is
where you get CorruptedViewState error messages. Consider this:

User John (ctl1)
User Jane (ctl2)
User Jim (ctl3)

Each of the users is a button

You click on Jane, however, between the time you got the page and the time
you clicked user Jane was deleted, a server will construct a list
User John (ctl1)
User Jim (ctl2)

Check which control you were trying to route an event to - that would be
ctl2; execute OnClick event delegate for User Jim. -

- Hope this helps


In summary - if you can avoid doing it do so - I had a catalog that was
working the exact same way; after 3 months of production I changed it to
redirect itself to its own page with Get Parameters instead of events. I did
it because every load of a page resulted in 2X work for the server (previous
state + current state).
it also removed a lot of complexity. I also know of a few that created
every! control on the page they might need and then made them visible or hid
them. Personally I don't like that style.

- Arthur

"ton" <(E-Mail Removed)> wrote in message
news:bvav9a$pjr$(E-Mail Removed)1.nb.home.nl...
> In the procedure CreateChildControls I add several controls like check and
> textboxes, button link and so on. How can I get the postback respons on

the
> button link:
> The functions:
> lblButtonLink_Command and lblButtonLink_Click will not be executed
>
> Please help
>
> Ton
>
>
>



 
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