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Binding to Data Using a Data Source Control

Data source controls greatly expand the capabilities of data-bound controls such as the GridView, FormView, and DetailsView controls. By working together, data source controls and data-bound controls let you retrieve, modify, page, sort, and filter data from different data sources with little or no code.

You can work with data in a data-bound control by binding the data-bound control to a data source control such as a LinqDataSource, ObjectDataSource, or SqlDataSource control. The data source control connects to a data source such as a database, entity class, or middle-tier object and then retrieves or updates data. The data-bound control can then use this data. To perform the binding, you set the data-bound control's DataSourceID property to point to a data source control. When a data-bound control is bound to a data source control, little or no additional code is required for data operations. The data-bound control can automatically take advantage of the data services provided by the data source control.

NoteNote

In earlier versions of ASP.NET, data-bound controls were bound to data by using the DataSource property. This required that you write code to handle operations such as displaying, paging, sorting, editing, and deleting data. Although you can bind controls to data by using the DataSource property (and use existing code), you can also performing data binding by using the DataSourceID property instead. In general, using the DataSourceID property provides more automatic functionality than using the DataSource property.

The following example shows a FormView control that is bound to a LinqDataSource control to display data from a database. For the example to work, you must create classes that represent the database and the table. You can create these classes by using the Object Relational Designer. For more information, see Object Relational Designer (O/R Designer).


<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormView Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <h3>FormView Example</h3>
        <table cellspacing="10"> 
          <tr>               
            <td valign="top">

              <asp:FormView ID="ProductsFormView"
                DataSourceID="LinqDataSource1"
                AllowPaging="true"
                runat="server">

                <HeaderStyle forecolor="white" backcolor="Blue" />                

                <ItemTemplate>
                  <table>
                    <tr>
                      <td align="right"><b>Product ID:</b></td>
                      <td><asp:Label id="ProductIDLabel" runat="server" Text='<%# Eval("ProductID") %>' /></td>
                    </tr>
                    <tr>
                      <td align="right"><b>Product Name:</b></td>
                      <td><asp:Label id="ProductNameLabel" runat="server" Text='<%# Eval("ProductName") %>' /></td>
                    </tr>
                    <tr>
                      <td align="right"><b>Category ID:</b></td>
                      <td><asp:Label id="CategoryIDLabel" runat="server" Text='<%# Eval("CategoryID") %>' /></td>
                    </tr>
                    <tr>
                      <td align="right"><b>Quantity Per Unit:</b></td>
                      <td><asp:Label id="QuantityPerUnitLabel" runat="server" Text='<%# Eval("QuantityPerUnit") %>' /></td>
                    </tr>
                    <tr>
                      <td align="right"><b>Unit Price:</b></td>
                      <td><asp:Label id="UnitPriceLabel" runat="server" Text='<%# Eval("UnitPrice") %>' /></td>
                    </tr>
                  </table>                 
                </ItemTemplate>

                <PagerTemplate>
                  <table>
                    <tr>
                      <td><asp:LinkButton ID="FirstButton" CommandName="Page" CommandArgument="First" Text="<<" RunAt="server"/></td>
                      <td><asp:LinkButton ID="PrevButton"  CommandName="Page" CommandArgument="Prev"  Text="<"  RunAt="server"/></td>
                      <td><asp:LinkButton ID="NextButton"  CommandName="Page" CommandArgument="Next"  Text=">"  RunAt="server"/></td>
                      <td><asp:LinkButton ID="LastButton"  CommandName="Page" CommandArgument="Last"  Text=">>" RunAt="server"/></td>
                    </tr>
                  </table>
                </PagerTemplate>

              </asp:FormView>

            </td>
          </tr>
        </table>

        <asp:LinqDataSource 
            ContextTypeName="NorthwindDataContext" 
            TableName="Products"
            ID="LinqDataSource1"  
            runat="server">
        </asp:LinqDataSource>

      </form>
  </body>
</html>


For more information about data source controls, see Data Source Web Server Controls.

The way that a data source control retrieves data is determined by the control itself. The ObjectDataSource control reads data by calling the method specified in the SelectMethod property. The following example shows an ObjectDataSource control that returns data by using the GetAllEmployees method of the EmployeeLogic class.


<%@ Page language="c#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1" />

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          typename="Samples.AspNet.CS.EmployeeLogic" />

    </form>
  </body>
</html>


For more information, see ObjectDataSource Web Server Control Overview.

The SqlDataSource and AccessDataSource controls select data by running a SQL query that is specified in the SelectCommand property. The following example shows a SqlDataSource control that returns data from the Employees table of the Northwind sample database:


<%@ Page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
    <form id="form1" runat="server">
      <asp:SqlDataSource
          id="SqlDataSource1"
          runat="server"
          DataSourceMode="DataReader"
          ConnectionString="<%$ ConnectionStrings:MyNorthwind%>"
          SelectCommand="SELECT LastName FROM Employees">
      </asp:SqlDataSource>

      <asp:ListBox
          id="ListBox1"
          runat="server"
          DataTextField="LastName"
          DataSourceID="SqlDataSource1">
      </asp:ListBox>

    </form>
  </body>
</html>


For more information, see Selecting Data Using the SqlDataSource Control.

When you use the LinqDataSource control, if you do not set its Select property, the control returns data for all the properties in the data class. You can specify a subset of properties or calculate new values by setting the Select property. The following example shows a LinqDataSource control that returns three properties from a data source that contains additional properties.


<asp:LinqDataSource 
    ContextTypeName="ExampleDataContext" 
    TableName="Products" 
    Select="new(Name, Category, Price)"
    ID="LinqDataSource1" 
    runat="server">
</asp:LinqDataSource>
<asp:GridView 
    DataSourceID="LinqDataSource1"
    ID="GridView1" 
    runat="server">
</asp:GridView>


The XmlDataSource does not let you select specific elements from the source XML data. However, you can specify a filter by using the XPath property. For more information, see Filtering Data Using the XmlDataSource Control.

The LinqDataSource, ObjectDataSource, and SqlDataSource controls can be configured so that users can modify data. For more information, see Modifying Data using Data Source Controls.

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