Accessing button in repeater control - asp.net

Question

I'm trying - quite unsuccessfully - to access a button inside a repeater control. I have a repeater set up on a page that displays movies that are currently showing in cinemas. I have created two buttons and added them to the repeater - one for trailer and another for review. For the review I want to link to another page which will have another repeater with paging enabled. When a users clicks the review button they should be brought to a page that shows only the reviews for that specific movie. This is that code I have:
MARKUP:
The repeater:
<asp:Repeater ID="movies" runat="server">
<ItemTemplate>
<table width="641px">
<tr>
<td>
<span style="font-weight:bold;font-size:16px;">
<%# Container.DataItem("MovieTitle")%>
</span>
</td>
<td>
<span style="float:right;">
<asp:Image ID="Image1" runat="server" ImageUrl = '<%# Eval("Total")%>' style="width:80px;height:14px;"/>
</span>
</td>
</tr>
<tr>
<td colspan="2">
<hr style="height:1px;border-bottom:none;color:#e3e3e3;"/>
</td>
</tr>
</table>
<table width="641px">
<tr>
<td>
<asp:Image ID="Image2" runat="server" ImageUrl = '<%# Eval("MovieImageFileName")%>' style="width:180px;height:108px;border:1px solid #e3e3e3;"/>
</td>
<td style="vertical-align:top;">
<%# Container.DataItem("Synopsis")%>
</td>
</tr>
</table>
<table width="641px">
<tr>
<td>
<span style="float:right">
<asp:Button ID="btnTrailer" runat="server" Text="Trailer" BackColor="#FF9900" ForeColor="White" />
<asp:Button ID="btnReview" runat="server" Text="Review" BackColor="#FF9900" ForeColor="White" CommandName="Review" />
</span>
</td>
</tr>
<tr>
<td>
<hr style="height:1px;border-bottom:none;color:#e3e3e3;"/>
</td>
</tr>
</table>
</ItemTemplate>
</asp:Repeater>
CodeBehind:
Dim movie_title As String
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
Dim myConn As New OleDbConnection
Dim cmd As New OleDbCommand
Dim dr, aDataReader As OleDbDataReader
Dim query, movieID As String
movie_title = Request.QueryString("id")
myConn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source = " & _
Server.MapPath("/App_Data/MovieBoard.accdb"))
myConn.Open()
Dim sqlQuery = "Select movieID From Movies"
Dim aCmd = New OleDbCommand(sqlQuery, myConn)
aDataReader = aCmd.ExecuteReader()
If aDataReader.Read() = True Then
movieID = aDataReader(0)
Else
movieID = "0"
End If
query = ("Select MovieTitle, Genre, Synopsis, Starring, Total, Director, MovieImageFileName From Movies, MovieReviews, MReviewRatings WHERE Movies.MovieID = MovieReviews.MovieID AND MovieReviews.MReviewID = MReviewRatings.MReviewID AND ReviewerTypeID = 1")
cmd = New OleDbCommand(query, myConn)
dr = cmd.ExecuteReader()
movies.DataSource = dr
movies.DataBind()
End Sub
Protected Sub movies_ItemCommand(source As Object, e As RepeaterCommandEventArgs) Handles movies.ItemCommand
If e.CommandName = "Review" Then
Response.Redirect("testingreviews.aspx?id = '" & movie_title)
End If
End Sub
When I run page the page displays but when I click the review button I get the following error:
Invalid postback or callback argument. Event validation is enabled using <pages enableEventValidation="true"/>
in configuration or <%# Page EnableEventValidation="true" %> in a page. For security purposes, this feature verifies that arguments to postback or
callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.
RegisterForEventValidation method in order to register the postback or callback data for validation.
Anyone any ideas on what I am doing wrong? I am very new to asp.net.

Answer 1

If you want to access a button use the event ItemCreated or maybe its ItemDataBound.
Handles movies.ItemCreated
In that event you can then refeer to the button using FindControl,
Something like this
Sub Movies_ItemDataBound(Sender As Object, e As RepeaterItemEventArgs) Handles movies.ItemDataBound
Dim Btn As Button = CType(e.Item.FindControl("ButtonName"),Button)
End Sub