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.

Export ASP.Net Repeater Control to Excel File

In this article I will explain how to export ASP.Net Repeater control to Microsoft Excel file.

HTML Markup

Below is a simple ASP.Net Repeater Control and an ASP.Net Button to export the Repeater contents to Excel.

<asp:Repeater ID="rptCustomers" runat="server">

    <ItemTemplate>

        <table border = "1">

            <tr>

                <td style = "width:100px">

                    <%#Eval("CustomerID") %>

                </td>

                    <td style = "width:100px">

                    <%#Eval("City") %>

                </td>

                    <td style = "width:100px">

                    <%#Eval("PostalCode")%>

                </td>

            </tr>

        </table>

    </ItemTemplate>

</asp:Repeater>

<br />

<asp:Button ID="btnExport" runat="server" Text="Export" OnClick = "ExportToExcel" />

 

Namespaces

You will need to import the following namespaces.

C#

using System.IO;

using System.Data;

 

VB

Imports System.IO

Imports System.Data

 

 

Export To Excel

On the click of the Export button the following event handler is executed which exports the ASP.Net Repeater contents to Excel.

C#

protected void ExportToExcel(object sender, EventArgs e)

{

    Response.Clear();

    Response.Buffer = true;

    Response.AddHeader("content-disposition", "attachment;filename=RepeaterExport.xls");

    Response.Charset = "";

    Response.ContentType = "application/vnd.ms-excel";

    StringWriter sw = new StringWriter();

    HtmlTextWriter hw = new HtmlTextWriter(sw);

    rptCustomers.RenderControl(hw);

    Response.Output.Write(sw.ToString());

    Response.Flush();

    Response.End();

}

 

VB

Protected Sub ExportToExcel(sender As Object, e As EventArgs)

    Response.Clear()

    Response.Buffer = True

    Response.AddHeader("content-disposition", "attachment;filename=RepeaterExport.xls")

    Response.Charset = ""

    Response.ContentType = "application/vnd.ms-excel"

    Dim sw As New StringWriter()

    Dim hw As New HtmlTextWriter(sw)

    rptCustomers.RenderControl(hw)

    Response.Output.Write(sw.ToString())

    Response.Flush()

    Response.End()

End Sub