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custom control viewstate problem - please help so i can sleep

Hi, can someone please help me with my custom control viewstate problem....I
haven't slept for hours trying to get this fixed.

I am making two custom controls which will be included on a single page. For
now, I will call them box1 and box2. Each box has a panel and will display a
list of link buttons on the panel.
When the page loads for the first time, box1 will call the database and
create a list of linkbuttons and each link button has a CommandArgument
which represents an ID that will be passed on to box2.

I defined a custom event in box1 which will be fired when a linkbutton is
clicked. In my default.aspx, I capture that event and extract the
commandargument , and then set the ID property of box2 and load another set
of linkbuttons in box2 for that id.

it kinda works for the first half right now, i can load box2's linkbuttons
for the correct id on page postback, however, my problem is that if a
linkbutton in box2 is clicked, when the page reloads, i lose all the
linkbuttons in box2.

I know I need to recreate all the controls in box2 on every postback. But I
just can't get it to work.

My questions are:

First, Is it a good or bad idea to use custom event + property setter to
pass data between controls and trigger the loading of the second box?

I have tried to override the OnInit, CreateChildCont rols(), OnPrerender(),
etc in box2, to check if the ID is in the viewstate from box1, if it is
there, I call the LoadInfoObject( ) method directly. But it didn't work,
viewstate was always null.
so the second question is how and when should I store the ID from box1 in
the viewstate? in which method in box2 can i access that viewstate?

I have attached my code below.

Please enlighten me.

InfoChannelsLis tViewer.cs

public event MyEventHandler SelectedInfoCha nnelChanged;

public InfoChannelsLis tViewer() {} //ctor

protected override void CreateChildCont rols()
Panel infoChannelsPan el = new Panel();
infoChannelsPan el.EnableViewSt ate = true;
Controls.Add(in foChannelsPanel );

foreach (InfoChannel channel in Db.GetInfoChann els()
LinkButton lbtnInfoChannel = new LinkButton();
lbtnInfoChannel .CommandName = "SelectInfoChan nel";
lbtnInfoChannel .CommandArgumen t = channel.ID.ToSt ring();
lbtnInfoChannel .Text = channel.Name;
lbtnInfoChannel .Click += new
EventHandler(lb tnInfoChannel_C lick);

infoChannelsPan el.Controls.Add (lbtnInfoChanne l);

void lbtnInfoChannel _Click(object sender, EventArgs e)
if (sender is LinkButton)
LinkButton btn = sender as LinkButton;
if (btn.CommandNam e == "SelectInfoChan nel")
//store channel id in viewstate
ViewState["InfoChanne lId"] = btn.CommandArgu ment;

//raise Channel Changed event
MyEventArgs arg = new MyEventArgs
(MyEventType.In foChannelEvent, Convert.ToInt32 (btn.CommandArg ument));
SelectedInfoCha nnelChanged(thi s, arg);

InfoObjectListV iewer.cs

private int _infoChannelId;

public int InfoChannelId
get { return _infoChannelId; }
_infoChannelId = value;
if (_infoChannelId 0)
LoadInfoObject( _infoChannelId) ;

private void LoadInfoObject( int infoChannelId)
Panel panel2 = new Panel();
this.Controls.A dd(panel2);

foreach (InfoObject obj in Db.GetInfoObjec ts(infoChannelI d)
LinkButton infoObjectButto n = new LinkButton();
panel2.Controls .Add(infoObject Button );

infoObjectButto n.CommandName = "SelectInfoObje ct";
infoObjectButto n.CommandArgume nt = obj.ID.ToString ();
infoObjectButto n.Text = obj.Title;
infoObjectButto n.Click += new
EventHandler(in foObjectButtonS endID_Click);

void infoObjectButto nSendID_Click(o bject sender, EventArgs e)
if (sender is LinkButton)
LinkButton btn = sender as LinkButton;
if (btn.CommandNam e == "SelectInfoObje ct")
this.Page.Sessi on["InfoObject ID"] = btn.CommandArgu ment;
//TODO: further update

Oct 11 '06 #1
0 1657

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