Gridview rowcommand event not firing in dynamically added usercontrol - asp.net

Question

I have a usercontrol with gridview and rowcommand event.
This usercontrol is added dynamically using LoadControl on a button click of a page. The gridview's rowcommand doesn't fire.
Here is the code that loads the usercontrol on button click:
Protected Sub btnSearch_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSearch.Click
'<ucTitle:SearchList ID="ucSearchList" runat="server" Visible="false" />
Dim ucSearchList As TitleSearchList = LoadControl("~/Controls/TitleSearchList.ascx")
ucSearchList.ISBN = txtSearchISBN.Text
ucSearchList.LoadTitleSearchList()
pnlSearchResults.Controls.Add(ucSearchList)
End Sub
And here is the code in usercontrol
Public Class TitleSearchList
Inherits System.Web.UI.UserControl
Public Property ISBN As String
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadTitleSearchList()
End If
End Sub
Public Sub LoadTitleSearchList()
Dim _isbn As String = ISBN
Dim titles As New List(Of Title)
titles = New List(Of Title) From {
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"}
}
gvTitle.DataSource = titles
gvTitle.DataBind()
End Sub
Public Sub gvTitle_Rowcommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles gvTitle.RowCommand
If e.CommandName = "TitleDetail" Then
Response.Redirect("TitleSearch.aspx?isbn=" & e.CommandArgument().ToString())
End If
End Sub
End Class

Answer 1

Events in GridViews that are added dynamically in a UserControl get a little ugly. Since UserControls that are added dynamically have to be re-added on the post-back, you have to rebind the GridView DataSource, which makes you lose out on automatically getting those Events fired for you. That being said, you can still pull it off with some parsing of the __EVENTTARGET of the Form.
Add a HiddenField that tells you whether or not you need to re-add the UserControl. Add this in your Page_Load Event Handler:
If CBool(hdnTitleSearchActive.Value) = True Then
AddSearchListToPanel()
End If
Call AddSearchListToPanel() in your btnSearch_Click Event Handler.
Now this implementation of AddSearchListToPanel can be cleaned up some, but this should be good enough to get you going. Note that the Button triggering the GridView Command in my example has the ID of lbtTest. You will have to adjust based on the ID that you are using.
Private Sub AddSearchListToPanel()
Dim ucSearchList As TitleSearchList = LoadControl("~/Controls/TitleSearchList.ascx")
ucSearchList.ISBN = txtSearchISBN.Text
ucSearchList.LoadTitleSearchList()
pnlSearchResults.Controls.Add(ucSearchList)
hdnTitleSearchActive.Value = True
Dim strEventTarget As String = HttpContext.Current.Request.Form("__EVENTTARGET")
If Not strEventTarget Is Nothing AndAlso strEventTarget.Contains("gvTitle$") AndAlso _
strEventTarget.Contains("$lbtTest") Then
'Value example = gvTitle$ctl02$lbtTest
Dim intRowNumber As Integer = (CInt(strEventTarget.Substring(11, 2)) - 1)
Dim lbtCommandSource As LinkButton = CType(CType(ucSearchList.FindControl("gvTitle"), GridView).Rows(intRowNumber).FindControl("lbtTest"), LinkButton)
Dim objCommandEventArguments As New CommandEventArgs(lbtCommandSource.CommandName, lbtCommandSource.CommandArgument)
Dim objGridViewCommandEventArgs As New GridViewCommandEventArgs(lbtCommandSource, objCommandEventArguments)
ucSearchList.gvTitle_Rowcommand(lbtCommandSource, objGridViewCommandEventArgs)
End If
End Sub