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C# - Conditional Statements within Repeater Control?

Posted on 2004-08-02
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Last Modified: 2012-06-27
My code is below.  It currently loops through the record, displays a header and a table containing data.  No problem, that works.  However, I'm wondering how I can change the code so that a row isn't displayed if the cell is empty.  For example, if the 'event_location' field is empty, I don't want it to display the entire table row (<tr>).  How can I do that?  Embedding IF statements didn't work for me (or at least, I didn't have the correct syntax).  Please advise.

=================================

<%@ Page Language="C#" Debug="true" %>

   <script language="C#" runat="server">
    void Page_Load(Object semder, EventArgs e) {

      if (!Page.IsPostBack)
      {
          
          // CREATE SQL CONNECTION
          SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["connString"]);
          DataSet ds = new DataSet();
          
          // LOAD AND DISPLAY ANNOUNCEMENTS
          string sSQL = "SELECT * FROM mytable";

          SqlDataAdapter da = new SqlDataAdapter(sSQL, conn);

          da.Fill(ds, "IS_IN_MESSAGE_TBL");

          announcements.DataSource = ds.Tables[0].DefaultView;
          announcements.DataBind();
          
      }
    }

   </script>

<html><body>

    <ASP:Repeater id="announcements" runat="server">
      <ItemTemplate>
            <h3><%# DataBinder.Eval(Container.DataItem, "event_name") %></h3>

            <table>
               <tr>
                  <td>Location: </td>
                  <td><%# DataBinder.Eval(Container.DataItem, "event_location") %></td>
               </tr>
               <tr>
                  <td>Description: </td>
                  <td><%# DataBinder.Eval(Container.DataItem, "description") %></td>
               </tr>
               <tr>
                  <td>Contact: </td>
                  <td><%# DataBinder.Eval(Container.DataItem, "contact") %></td>
               </tr>
            </table>

      </ItemTemplate>
    </ASP:Repeater>

</body></html>
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Question by:hendridm
6 Comments
 
LVL 14

Expert Comment

by:dfu23
Comment Utility
you wouldn't want to just simply databind the repeater to the dataset then ...

you need to iterate through the dataset and check for the condition that you want and then add it to your repeater ...

or you should change your SQL to not return the rows that meet your condition ...

SELECT * FROM mytable WHERE event_location IS NOT NULL
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Author Comment

by:hendridm
Comment Utility
Iterating through the dataset with conditional statements would work, however, I thought the point of ASP.NET was separating code from content, so I was trying to do it the "ASP.NET way" with the repeater control and not embedding code in the content.  I will do that if there is no better way.

Regarding the modified SELECT statement, I don't want to eliminate records that have a null event_location - I still want to display the other data.  Classic ASP example:

<% Do Until rs.EOF %>

          <h3><%=rs("event_name")%></h3>

          <table>
             <% If rs("event_location") <> "" Then %>
             <tr>
                <td>Location: </td>
                <td><%=rs("event_location")%></td>
             </tr>
             <% End If %>
             <tr>
                <td>Description: </td>
                <td><%=rs("description")%></td>
             </tr>
             <tr>
                <td>Contact: </td>
                <td><%=rs("contact")%></td>
             </tr>
          </table>

<% rs.MoveNext:Loop %>

As you can see, it doesn't display the location row if the record is empty, however, it still displays the other rows.  I can do a similar method with C#, however, I was hoping to do it the "ASP.NET way".

I'm trying to learn ASP.NET, and it's a pain in the ass!  I want to do things the right way, not the ASP way - otherwise I lose all the advantages over ASP.
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LVL 14

Expert Comment

by:dfu23
Comment Utility
Instead of using a repeater use a datalist ... within the datalist ... in the items template create a table control <asp:table> and then create a row crontrol within the table <asp:tablerow> ... and within the table row (or table rows) create a table cell <asp:tablecell>

the table cell will contain the data and give each one an ID, along with the table rows and the table itself

then use the event onitemdatabound call a function to check if that item's data is null ... in your case the event_location

if it's null find the control within the datalist that contains the event location and set its visibility to false.
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LVL 24

Assisted Solution

by:Justin_W
Justin_W earned 50 total points
Comment Utility
See my answer in this PAQ:
http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/ASP_DOT_NET/Q_21044921.html

It shows how you can conditionally output arbitrary text at any location(s) within a Repeater's ItemTemplate.

Or you could do something like:

     <ItemTemplate>
          <h3><%# DataBinder.Eval(Container.DataItem, "event_name") %></h3>

          <table>
<asp:panel runat=server Visible="<%# (Len(DataBinder.Eval(Container.DataItem, "event_location")) < 1) %>" >
             <tr>
                <td>Location: </td>
                <td><%# DataBinder.Eval(Container.DataItem, "event_location") %></td>
...
</asp:panel>
0
 
LVL 28

Expert Comment

by:mmarinov
Comment Utility
Hi hendridim,

you can do it in this way

if (!IsPostBack)
            {
                SqlConnection _con = new SqlConnection();
                SqlCommand _com = new SqlCommand();
                DataSet _ds = new DataSet();
                SqlDataAdapter _da = new SqlDataAdapter();

                _con.ConnectionString = "ConfigurationSettings.AppSettings["connString"]";
                _com.Connection = _con;
                _com.CommandText = "SELECT * FROM mytable";
                _com.CommandType = CommandType.Text;

                _da.SelectCommand = _com;
                _da.Fill( _ds, IS_IN_MESSAGE_TBL );

                Repeater1.DataSource = _ds.Tables[0].Select("event_location IS NOT NULL");
                Repeater1.DataBind();

            }

But in your repeater you have to do some changes like

 <ASP:Repeater id="announcements" runat="server">
     <ItemTemplate>
          <h3><%# DataBinder.Eval(Container.DataItem, "[event_name]") %></h3>

          <table>
             <tr>
                <td>Location: </td>
                <td><%# DataBinder.Eval(Container.DataItem, "[event_location]") %></td>
             </tr>
             <tr>
                <td>Description: </td>
                <td><%# DataBinder.Eval(Container.DataItem, "[description]") %></td>
             </tr>
             <tr>
                <td>Contact: </td>
                <td><%# DataBinder.Eval(Container.DataItem, "[contact]") %></td>
             </tr>
          </table>

     </ItemTemplate>
    </ASP:Repeater>


B..M
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LVL 14

Accepted Solution

by:
dfu23 earned 450 total points
Comment Utility
<%@ Page Language="C#" Debug="true" %>

   <script language="C#" runat="server">
    void Page_Load(Object semder, EventArgs e) {

     if (!Page.IsPostBack)
     {
         
         // CREATE SQL CONNECTION
         SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["connString"]);
         DataSet ds = new DataSet();
         
         // LOAD AND DISPLAY ANNOUNCEMENTS
         string sSQL = "SELECT * FROM mytable";

         SqlDataAdapter da = new SqlDataAdapter(sSQL, conn);

         da.Fill(ds, "IS_IN_MESSAGE_TBL");

         announcements.DataSource = ds.Tables[0].DefaultView;
         announcements.DataBind();
         
     }
    }

   </script>

<html><body>

    <ASP:Repeater id="announcements" runat="server">
     <ItemTemplate>
          <h3><%# DataBinder.Eval(Container.DataItem, "event_name") %></h3>

          <asp:table runat="server">
             <asp:tablerow runat="server" Visible='<%# (DataBinder.Eval(Container.DataItem, "event_location") == null) %>'>
                <asp:tablecell runat="server">Location: </asp:tablecell>
                <asp:tablecell runat="server"><%# DataBinder.Eval(Container.DataItem, "event_location") %></asp:tablecell>
             </asp:tablerow>
             <asp:tablerow runat="server">
                <asp:tablecell runat="server">Description: </asp:tablecell>
                <asp:tablecell runat="server"><%# DataBinder.Eval(Container.DataItem, "description") %></asp:tablecell>
             </asp:tablerow>
             <asp:tablerow runat="server">
                <asp:tablecell runat="server">Contact: </asp:tablecell>
                <asp:tablecell runat="server"><%# DataBinder.Eval(Container.DataItem, "contact") %></asp:tablecell>
             </asp:tablerow>
          </asp:table>

     </ItemTemplate>
    </ASP:Repeater>

</body></html>
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