whats the best way to pass data to user components in asp.net?

Question

its .net 2.0 here, not MVC, and im crap at asp forms :(.

So yeah, ive got a page with user controls on it. When i click on something in the page, i want to load the usercontrol based on a parameter from the page.

Problem is i cant do it.

In my page's FaultTree_Clicked, i get the value, then ive tried a variety of things:

• I tried exposing a property on the child user control to set the value, which i set in FaultTree_Clicked, it gets forgotten.

• I tried saving it to Session["mykey"], and loading Session["mykey"] in the control's Page_init... the value is blank.

• I tried saving it to ViewState["mykey"], and loading ViewState["mykey"] in the control's Page_init... the value is blank.

EDIT: ok more specific info: Heres a cut down version of what the page(MyFault) looks like:

<form id="form" runat="server">
 <div id="faulttree">
   <asp:TreeView ID="FaultTree" ......>
 </div>
 <uc1:_DefectDetail ID="DefectDetail" runat="server" Visible="true" EnableViewState="true" />
</form>

And theres a method on the pages codebehind "FaultTree_SelectedNodeChanged()".

When that method is hit, I want to load/show the DefectDetail control. The DefectControl requires a faultid, which comes off the Tree, which i successfully get in the SelectedNodeChanged method. I cant get the faultid into the defect control.

Answer 1

This has to do with ASP.NET page lifecycle. By the time the click event fires, the control's init event has already happened.

In order to better assist you, please provide a more detailed explanation of what the FaultTree control is, what is the desired result and some sample code.

UPDATE:

Instead of a public property, you can simply create a public method in the control that does the desired action and invoke it from the FaultTree_SelectedNodeChangeEvent.

Example (for a public method named Refresh):

_DefectDetail.Refresh(object data);

Answer 2

Basically you have to use EventHandlers....

        1. Add a event handler to your user control (I had a search bar UscSearchCriteriaBar1)   

        public event EventHandler CriteriaChanged;

        +


        private void InternalOnCriteriaChanged()
        {
        OnCriteriaChanged();
        }
        +
        protected virtual void OnCriteriaChanged()
        {
        // If there are registered clients raise event
        if (CriteriaChanged != null)
        CriteriaChanged(this, EventArgs.Empty);
        }
        +
        Example
        public int EmployeeID
        {
        get
        {
        f (Session["EmployeeID"] != null)
        {
        ViewState["EmployeeID"] = Convert.ToInt32(Session["EmployeeID"]);
        }
        if (ViewState["EmployeeID"] == null)
        ViewState["EmployeeID"] = 0;
        return int.Parse(ViewState["EmployeeID"].ToString());
        }
        set
        {
        ctlEmployee.SelectedValue = value.ToString();
        ViewState["EmployeeID"] = value;
        Session["EmployeeID"] = value;
        }
        }


        In your page or other control


        override protected void OnInit(EventArgs e)
        {
        InitializeComponent();
        UscSearchCriteriaBar1.CriteriaChanged += new EventHandler(this.CriteriaChanged);    
        base.OnInit(e);
        }

        private void CriteriaChanged(object sender, EventArgs e)
        {
        try
        {
RefreshData();
        }
        catch (Exception ex)
        {
        ExceptionManager.Publish(ex);
        }
        }

    You can get UscSearchCriteriaBar1.EmployeeID

This code should give you some ideas...was done for 1.1 should work on 2.