How can I use Eval in asp.net to read fields from a database?

Question

Here is the situation:

I have a webform that needs to read specific fields from a database that uses the eval function in the .aspx page. I know how to assign the values in the .aspx page, but in the code behind how do I "get" the values and bind them to the .aspx page? Can I just used a datareader? Dataset? What exactly am I going to be binding or reading to the dataset or reader? Do I need to create a method?

I already have the stored procedure created to pull the data from the database. I was going to create a method with the stored procedure. I just dont which kind to create...dataset, datareader? And how do I code it in the code behind?

Michael C. Gates · Accepted Answer · 2011-12-01 19:46:50Z

0

Declare public properties for your DB fields:

public int MyFieldID = 0;
public string MyStringFromDB = string.empty;

// PAGE LOAD GET DB VALUES
{
    MyFieldID = Convert.ToInt32(db["ID"]);
    MyStringFromDB = Convert.ToString(db["FIELD"]);
}

Now you can either just assign them in the aspx page like <%=MyFieldID%> or use them in the code behind.

answered Dec 1, 2011 at 19:46

Michael C. Gates

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2 Comments

Jeff Over a year ago

Ok, great! So should I get the intial data from the database using a datareader and then assign values to the fields?

Michael C. Gates Over a year ago

Yes, you can use a data reader, data table, or any other data source. I usually return my data sets as data tables. But it's your personal choice. Just remember, DataBinder is only for when you bind data to a control (DataGrid, as an example). I was a Classic ASP developer, and this was hard for me to grasp.

jrummell · Accepted Answer · 2011-12-01 19:51:28Z

0

See Walkthrough: Displaying Data Using a Stored Procedure in the GridView Web Server Control

You can only use DataBinder.Eval within the context of a data bound control such as GridView, Repeater, DataGrid, etc. See DataBinder Class:

<%@ Page Language="C#" %>
<%@ Import Namespace="ASPSample" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void  Page_Load(object sender, EventArgs e)
{
        // Create and populate an ArrayList to store the products.
        ArrayList ProductList = new ArrayList();
        ProductList.Add(new Product("Standard", 99.95));
        ProductList.Add(new Product("Deluxe", 159.95));

        // Bind the array list to Repeater
        ListRepeater.DataSource = ProductList;
        ListRepeater.DataBind();
}
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>DataBinder Example</title>
</head>
<body>
<form id="Form2" runat="server">
<table>
<asp:Repeater id="ListRepeater" runat="server">
    <HeaderTemplate>
    <tr>
        <th style="width:50; text-align:left">Model</th>
        <th style="width:100; text-align:right">Unit Price</th>
    </tr>
    </HeaderTemplate>
    <ItemTemplate>
    <tr>
        <!-- Databind to the Product information using the DataBinder methods. 
             The Container.DataItem refers to the ArrayList object bound to 
             the ASP:Repeater in the Page Load event. -->
        <td>
            <%#DataBinder.GetPropertyValue(Container.DataItem, "Model")%>
        </td>
        <!-- Format the UnitPrice as currency. ({0:c}) -->
        <td style="text-align:right">
            <%#DataBinder.GetPropertyValue(Container.DataItem,
                         "UnitPrice", "{0:c}")%>
        </td>
    </tr>
    </ItemTemplate>
</asp:Repeater>
</table>
</form>
</body>
</html>

edited Dec 1, 2011 at 19:51

answered Dec 1, 2011 at 19:33

jrummell

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4 Comments

Jeff Over a year ago

I am not displaying in a gridview. Im using the EVAL function in the .aspx page.

Jeff Over a year ago

Example of the field I want to load on the .aspx page:Strength: <%# DataBinder.Eval(Container.DataItem, "Strength")%>

Michael C. Gates Over a year ago

That will only work if you are using a GridView, Repeater, etc. with a datasource bound to it.

techBeginner Over a year ago

@user1049984: try with <%# DataBinder.Eval(Page, "Strength")%>..not sure about it..

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