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FormView.DataKey Property

Gets a DataKey object that represents the primary key of the displayed record.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

[BrowsableAttribute(false)]
public virtual DataKey DataKey { get; }

Property Value

Type: System.Web.UI.WebControls.DataKey
A DataKey object that represents the primary key of the displayed record.

When the DataKeyNames property is set, the FormView control automatically creates a DataKey object that contains the key/value pairs of the field or fields listed in the DataKeyNames property for the current record. Use the DataKey property to get this DataKey object. This property is commonly used to obtain the keys and their corresponding values for the fields specified in the DataKeyNames property.

NoteNote

As a shortcut, you can also use the SelectedValue property to determine the value of the first key field listed in the DataKeyNames property.

The following example demonstrates how to use the DataKey property to determine the value of the key field.


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

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

  void EmployeeFormView_ItemCreated(Object sender, EventArgs e)
  {
    DataKey key = EmployeeFormView.DataKey;
    MessageLabel.Text = "The key value is " + key.Value.ToString() + ".";
  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>FormView DataKey Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>FormView DataKey Example</h3>

      <asp:formview id="EmployeeFormView"
        datasourceid="EmployeeSource"
        allowpaging="true"
        datakeynames="EmployeeID"
        onitemcreated="EmployeeFormView_ItemCreated"  
        runat="server">

        <itemtemplate>

          <table>
            <tr>
              <td>
                <asp:image id="EmployeeImage"
                  imageurl='<%# Eval("PhotoPath") %>'
                  alternatetext='<%# Eval("LastName") %>' 
                  runat="server"/>
              </td>
              <td>
                <h3><%# Eval("FirstName") %>&nbsp;<%# Eval("LastName") %></h3>      
                <%# Eval("Title") %>        
              </td>
            </tr>
          </table>

        </itemtemplate>

      </asp:formview>

      <br/><br/>

      <asp:label id="MessageLabel"
        forecolor="Red"
        runat="server"/>

      <!-- This example uses Microsoft SQL Server and connects  -->
      <!-- to the Northwind sample database. Use an ASP.NET     -->
      <!-- expression to retrieve the connection string value   -->
      <!-- from the Web.config file.                            -->
      <asp:sqldatasource id="EmployeeSource"
        selectcommand="Select [EmployeeID], [LastName], [FirstName], [Title], [PhotoPath] From [Employees]"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
        runat="server"/>

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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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