Accessing a button in a repeater from Code Behind (C#)

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

Because i want that only the author of that comment can delete it! In fact the visibility of the button is setted in a if statement that cheks the username — Salvatore
– Salvatore, Commented Apr 30, 2011 at 10:51

Off The Gold · Accepted Answer · 2016-02-19 15:48:11Z

3

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; 
    }
}

edited Feb 19, 2016 at 15:48

Off The Gold

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answered Apr 30, 2011 at 10:58

Muhammad Akhtar

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Comments

Ankur · Accepted Answer · 2011-04-30 09:54:05Z

0

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");

answered Apr 30, 2011 at 9:54

Ankur

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1 Comment

Salvatore Over a year ago

If I change code in this way the error object reference not set appears.

protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)         {                                              Button btn = new Button();                     btn = (Button)e.Item.FindControl("btnDeleteComment");                     btn.Visible = false;                                         }

Govind Malviya · Accepted Answer · 2011-04-30 10:57:48Z

0

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();

edited Apr 30, 2011 at 10:57

answered Apr 30, 2011 at 10:37

Govind Malviya

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1 Comment

Salvatore Over a year ago

Ok i will try this method and I will let you know

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