Accessing a button in a repeater from Code Behind (C#) - asp.net

Question

I am finding some serious problems in accessing a button placed in a repeater from code behind.
This is the repeater code:
<asp:Repeater ID="Repeater1" runat="server">
<HeaderTemplate></HeaderTemplate>
<ItemTemplate>
<table>
<tr>
<td>Username:</td>
<td> <%# Eval("UserName") %></td>
</tr>
<tr>
<td>Date:</td>
<td><%# Eval("CommentTime") %></td>
</tr>
<tr>
<td>Comment:</td>
<td><%# Eval("Comment") %></td>
</tr>
<tr>
<td>
<asp:Button ID="btnDeleteComment" runat="server" Text="Delete" /></td>
</tr>
</table>
<br />
</ItemTemplate>
</asp:Repeater>
And This is the code Behind placed int the page load:
Button btn = new Button();
btn = (Button)Repeater1.FindControl("btnDeleteComment");
btn.Visible = false;
Am I missing something?
Thanks

Answer 1

I am sure, I've solved your problem as to why you are getting the object reference not set.
As you have this conditional statement, if (e.Item.ItemType == ListItemType.Item), when its first iterates it will be a header item type. Since your your button is in the item template, that's doesn't exist in the Header template.
protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item)
{
Button btn = new Button();
btn = (Button)e.Item.FindControl("btnDeleteComment");
btn.Visible = false;
}
}

Answer 2

You can't find the control like this. What you need to do is attach an event to repeater "item data bound event" and in that event handler do:
(Button)e.Item.FindControl("btnDeleteComment");

Answer 3

on .aspx
<asp:Button ID="btnDeleteComment" runat="server" Text="Delete" Visible='<# IsAuthor?"true":"false" >' />
in code behind
//global scope
public bool IsAuthor=false;
//in pageload event
IsAuthor= GetIsAuthor();