Question

I am building an application where a page will load user controls (x.ascx) dynamically based on query string.

I have a validation summary on the page and want to update it from the User Controls. This will allow me to have multiple controls using one Validation Summary. How can I pass data between controls and pages.

I know I can define the control at design time and use events to do that but these controls are loaded dynamically using Page.LoadControl.

Also, I want to avoid using sessions or querystring.

Answer 1

Found a way of doing this:

Step 1: Create a Base User Control and define Delegates and Events in this control.

Step 2: Create a Public function in the base user control to Raise Events defined in Step1.

 'SourceCode for Step 1 and Step 2 Public Delegate Sub UpdatePageHeaderHandler(ByVal PageHeading As String) Public Class CommonUserControl     Inherits System.Web.UI.UserControl      Public Event UpdatePageHeaderEvent As UpdatePageHeaderHandler     Public Sub UpdatePageHeader(ByVal PageHeadinga As String)         RaiseEvent UpdatePageHeaderEvent(PageHeadinga)     End Sub End Class 

Step 3: Inherit your Web User Control from the base user control that you created in Step1.

Step 4: From your Web User Control – Call the MyBase.FunctionName that you defined in Step2.

 'SourceCode for Step 3 and Step 4 Partial Class DerievedUserControl     Inherits CommonUserControl      Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load         MyBase.PageHeader('Test Header')     End Sub End Class 

Step 5: In your page, Load the control dynamically using Page.LoadControl and Cast the control as the Base user control.

Step 6: Attach Event Handlers with this Control.

 'SourceCode for Step 5 and Step 6 Private Sub LoadDynamicControl()     Try         'Try to load control         Dim c As CommonUserControl = CType(LoadControl('/Common/Controls/Test.ascx', CommonUserControl))         'Attach Event Handlers to the LoadedControl         AddHandler c.UpdatePageHeaderEvent, AddressOf PageHeaders         DynamicControlPlaceHolder.Controls.Add(c)     Catch ex As Exception         'Log Error     End Try End Sub