CODEWITHSUNDEEP
asp.netwebforms
wonderful world
wonderful world

Reputation: 11599

Page_Load Vs Page_Init for the user control in a Page

I have a ASP.NET page called customer.aspx which has a user control customerdetails.ascx inside of it. This user control reads data from the database and populate some fields. If the loading is successful (if there is some data), the user should stay on the page. Otherwise the page should be redirected to a different page. This redirection is done in the container customer.aspx page and not in the control.

What are the ASP.NET page cycle events (Page_Load Vs Page_Init) that I should use for customer.aspx and customerdetails.ascx for the above logic to work?

Upvotes: 0

Views: 6248

Answers (2)

wazz
wazz

Reputation: 5058

I was rereading this - https://web.archive.org/web/20210330142645/http://www.4guysfromrolla.com/articles/092904-1.aspx, old, but good. I think you should be able to do what you need from the Page_Load event of customer.aspx because user controls are loaded by then. simply check the user control's controls for values and redirect, or not.

edit:

Actually, I think it depends. controls prob have to be preloaded, which changes things.

If we need our dynamically added controls to maintain their view state it is paramount that these controls be added before the Load View State stage. That is, these controls must exist within the page's control hierarchy before the view state is loaded. There's only one stage before Load View State - Initialization. That means, if we want our dynamic controls to persist view state we must add them to the control hierarchy in the page's Init event.

One way to make the user control accessible (answer at bottom): https://forums.asp.net/t/1674095.aspx?Loop+through+User+Controls+in+Content+Page

edit:

User Control

<h4>The User Control</h4>
<div>
    <asp:Label ID="lblUserCtrl" runat="server" Text="Label"></asp:Label>
</div>

.cs

public partial class Testing_Controls_TestCtrl : System.Web.UI.UserControl
{
    // public properties

    public Label lbl
    {
        get { return lblUserCtrl; }
        set { lblUserCtrl = value; }
    }
    public bool isLoaded;

    // end public properties.

    protected void Page_Init(object sender, System.EventArgs e)
    {
        lblUserCtrl.Text = "User ctrl loaded at: " + DateTime.Now;
        isLoaded = true;
    }

    protected void Page_Load(object sender, EventArgs e)
    {
    }
}

container page:

note: I still had to register the control even though I loaded it from code.

<%@ Register Src="~/Testing/Controls/TestCtrl.ascx" TagPrefix="uc1" TagName="TestCtrl" %>

...etc...

<form id="form1" runat="server">
    <h4>The Container Page</h4>

    <div>
        <asp:Label ID="lblContainerLabel" runat="server" Text="Label"></asp:Label>
    </div>
    <br />
    <hr />
    <asp:PlaceHolder ID="ph1" runat="server"></asp:PlaceHolder>
</form>

.cs

public partial class Testing_user_control_test : System.Web.UI.Page
{
    private bool ucIsLoaded;

    protected void Page_Init(object sender, System.EventArgs e)
    {
        Testing_Controls_TestCtrl c = (Testing_Controls_TestCtrl)Page.LoadControl("~/Testing/Controls/TestCtrl.ascx");
        ph1.Controls.Add(c);
        c.lbl.Text += "<br />This is text appended to the user control by the container page.";
        ucIsLoaded = c.isLoaded;
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        lblContainerLabel.Text = "Container page loaded at: " + DateTime.Now + "<br />The user control is loaded: " + ucIsLoaded.ToString().ToUpper();
    }
}

Upvotes: 1

Joel Coehoorn
Joel Coehoorn

Reputation: 415690

If you've established that both options work functionally, then, for performance, you should prefer Page_Init.

If you might end up with a redirect, then you want to give the server the chance to do that redirect as soon as possible in the page lifecycle, to avoid using resources on lifecycle steps that might not be necessary.

Upvotes: 1

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