Jason,
Thank you for the reply. I have tried your approach of putting all the
UserControls on the .aspx page and toggling the Visible attribute on
individual UserControls as needed. The only problem with this method is that
even though a page may not be visible, its Page_Load method is still called
for each UserControl on the page. This may or may not be a performance
problem depending on what initialization is going on in all the Page_Load
events. For instance, in your example, both "companyFinder" and "company"
are being loaded and perhaps populating DataTables with SQL data, however,
only one user control is being rendered. I suppose you could work around
this by using Session keys keep track of which control is to be loaded such
that Page_Load events will skip over their initialization code if the
selected control isn't specified by the Session key/value pair.
In the end I was thinking of having the RadioButtonList's
SelectedIndexChanged event do a Server.Transfer and apend a QueryString to
the URL, such as ...&View="SmallView.ascx" or ...&View="LargeView.ascx" that
identifies which control to load dynamically. In this case all the parent
..aspx page that loads the dynamic user control has to do is look at the
Request["View"] query string to know which control to load.
- Harry
"Jason Penniman" <jp*******@actcci.com> wrote in message
news:Od**************@TK2MSFTNGP11.phx.gbl...
I did something similar in an application I wrote... I ended up placing all
the controls on the page, hidden, then turned on the appropriate one.
The problem with your approach (which was my inital approach) is that the
event code is fired first. So, the dynamic control doesn't exist when a
parent event fires.
Here's what I did...
on the aspx page...
<asp:PlaceHolder ID="appArea" Runat="server"></asp:PlaceHolder>
<extn:companyFinder id="ctlCompanyFinder" runat="server" visible="false" />
<extn:company id="ctlCompany" runat="server" visible="false" />
then, in the code behind...
private void Page_Load(object sender, System.EventArgs e)
{
if (this.IsPostBack)
{
if (Session["_extn_control"] != null)
currentControl =
this.FindControl(Session["_extn_control"].ToString());
if (currentControl != null)
{
currentControl.Visible = true;
}
}
}
protected void MenuItemHandler(object sender, System.EventArgs e)
{
MenuItem item = (MenuItem)sender;
switch (item.ID)
{
case "mnuFindCompany":
ctlCompanyFinder.Visible = true;
Session["_extn_control"] = "ctlCompanyFinder";
break;
}//end switch item
}//end MenuItemHandler
I used a session variable to trake the name of the current control, but you
could certainly use viewstate.
"Harry" <ro******@vu.union.edu> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...
Hello,
I have a page with a RadioButtonList and a PlaceHolder control. The
RadioButtonList's AutoPostBack attribute is set to TRUE and its
SelectedIndexChanged event loads one of three UserControls into the
PlaceHolder's child control collection depending upon which of the three
radio buttons is selected. Each of the three UserControls have postback
events themselves triggered by button clicks. The problem I'm having is
keeping track of what UserControl to load upon a page being posted back.
My SelectedIndexChanged event will load a UserControl dynamically just fine,
however, in the event that the dynamically loaded user control itself
issues a postback the parnets Page_Load event must remeber which UserControl to
reload so it can handle its postback. In order to do this, I store the
loaded control's name in the ViewState. This solution causes a problem in
that moveing from one dynamically loaded UserControl to another will cause
two controls to be displayed at the same time. To fix this my
SelectedIndexChanged event will remove the first child control in the
PlaceHolder. However, this solution totally screws with my postback such
that they do not fire porperly. Here is an example of what I'm doing:
private void Page_Load(object sender, System.EventArgs e)
{
if (ViewState["ControlName"] != null)
PlaceHolderControl.Controls.Add(LoadControl(ViewSt ate["ControlName"].ToStrin g()));
}
private void MyRadioButtonList_SelectedIndexChanged(object sender,
System.EventArgs e)
{
if (PlaceHolderControl.HasControls())
PlaceHolderControl.Controls.RemoveAt(0);
ViewState["ControlName"] = MyRadioButtonList.SelectedValue;
PlaceHolderControl.Controls.Add(LoadControl(MyRadi oButtonList.SelectedValue) );
}
Any suggestions would be much appreciated.
- Harry
