Question

I have a user control that contains a repeater. It seems that data cannot be assigned to it’s DataSource property, I have tried a few different data sources but the following error is displayed: (I have debugged it and there are data items in the datasource)

Object reference not set to an instance of an object

Here’s the aspx for the repeater:

<asp:Repeater ID="repeater1" runat="server" >
    <HeaderTemplate>
        <ul>
    </HeaderTemplate>
        <ItemTemplate>
            <li>
                <%# Eval("Name") %>
            </li>
        </ItemTemplate>
    <FooterTemplate>
            </ul>
    </FooterTemplate>
</asp:Repeater>

I create an instance of the user control in the code behind of the file I want to display the repeater in – I can’t type repeater1.DataSource and assign it in that page so I added an attribute to the user control which takes IEnumerable as the datasource.

Any ideas why this isn’t working?

Answer 1

You should do such things in the DataBind() method like shown below:

public override void DataBind()
{
   this.repeater.DataSource = ...
   this.repeater.DataBind();
   ...
}

So it will bind whilst parent page calling Page.DataBind() as well

Control.DataBind Method:

Use this method to bind data from a source to a server control. This
method is commonly used after retrieving a dataset through a database
query. Most controls perform data binding automatically, which means
that you typically do not need to call this method explicitly.