Handling Empty Data in an ASP.NET Repeater control
Posted by: Suprotim Agarwal ,
on 2/12/2009,
in
Category ASP.NET
Abstract: The GridView has an EmptyDataText property or the that lets us handle EmptyData. However the Repeater has no such property or template. In this article, we will see how to adopt a simple technique to handle empty data in an ASP.NET Repeater control without creating a custom control.
Handling Empty Data in an ASP.NET Repeater control
The GridView has an EmptyDataText property or the <EmptyDataTemplate> that lets us handle EmptyData. However the Repeater has no such property or template. In this short article, we will see how to adopt a simple technique to handle empty data in an ASP.NET Repeater control without creating a custom control.
Drag and drop a Repeater and a SQLDataSource control to the page. Bind the Repeater to the SQLDataSource as you usually do
<div>
<asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1"
onitemdatabound="Repeater1_ItemDataBound">
<HeaderTemplate>
<table border="1" cellpadding="3" cellspacing="3">
<tr bgcolor="blue">
<td><b>CustomerID</b>
</td>
<td><b>CompanyName</b>
</td>
<td><b>ContactName</b>
</td>
<td><b>ContactTitle</b></td>
</tr>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<%#DataBinder.Eval(Container.DataItem, "CustomerID")%>
</td>
<td>
<%#DataBinder.Eval(Container.DataItem, "CompanyName")%>
</td>
<td>
<%#DataBinder.Eval(Container.DataItem, "ContactName")%>
</td>
<td>
<%#DataBinder.Eval(Container.DataItem, "ContactTitle")%>
</td>
</tr>
</ItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [CustomerID], [CompanyName], [ContactName],
[ContactTitle], [Address] FROM [Customers] " >
</asp:SqlDataSource>
</div>
In your web.config, add a connection string as shown below:
<connectionStrings>
<add name="NorthwindConnectionString" connectionString="Data Source =(local);Integrated Security = SSPI; Initial Catalog=Northwind;"/>
</connectionStrings>
If you run the application, the repeater would display the data from the database. Now change the query so that it returns empty data.
SELECT [CustomerID], [CompanyName], [ContactName], [ContactTitle], [Address] FROM [Customers] WHERE CUSTOMERID=’XYZ’
On running the application, you would see the following:
Now this display is not elegant enough to inform the user that there is no data, right? So let us see how to display a message in the Repeater control when there is no data present.
In the <FooterTemplate>, add a Label with some empty data text and set its visible property to false.
<FooterTemplate>
<tr>
<td>
<asp:Label ID="lblEmptyData"
Text="No Data To Display" runat="server" Visible="false">
</asp:Label>
</td>
</tr>
</table>
</FooterTemplate>
Now add an ItemDataBound event to the Repeater
<asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1"
onitemdatabound="Repeater1_ItemDataBound">
In the code behind, write the following code:
C#
protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (Repeater1.Items.Count < 1)
{
if (e.Item.ItemType == ListItemType.Footer)
{
Label lblFooter = (Label)e.Item.FindControl("lblEmptyData");
lblFooter.Visible = true;
}
}
}
VB.NET
Protected Sub Repeater1_ItemDataBound(ByVal sender As Object, ByVal e As RepeaterItemEventArgs)
If Repeater1.Items.Count < 1 Then
If e.Item.ItemType = ListItemType.Footer Then
Dim lblFooter As Label = CType(e.Item.FindControl("lblEmptyData"), Label)
lblFooter.Visible = True
End If
End If
End Sub
The code checks if the Repeater has items in it. If the items count is less than 1, the code uses the FindControl() to locate the label and set it to visible.
On running the application again, you get to see the message 'No Data To Display' as shown in the screenshot below. This is certainly more user friendly than letting the user wonder why the data was not displayed at the first place.
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Suprotim Agarwal, MCSD, MCAD, MCDBA, MCSE, is the founder of
DotNetCurry,
DNC Magazine for Developers,
SQLServerCurry and
DevCurry. He has also authored a couple of books
51 Recipes using jQuery with ASP.NET Controls and
The Absolutely Awesome jQuery CookBook.
Suprotim has received the prestigious Microsoft MVP award for ten consecutive times. In a professional capacity, he is the CEO of A2Z Knowledge Visuals Pvt Ltd, a digital group that offers Digital Marketing and Branding services to businesses, both in a start-up and enterprise environment.
Get in touch with him on Twitter @suprotimagarwal or at LinkedIn