FormView.DataKey Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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

public:
 virtual property System::Web::UI::WebControls::DataKey ^ DataKey { System::Web::UI::WebControls::DataKey ^ get(); };

[System.ComponentModel.Browsable(false)]
public virtual System.Web.UI.WebControls.DataKey DataKey { get; }

[<System.ComponentModel.Browsable(false)>]
member this.DataKey : System.Web.UI.WebControls.DataKey

Public Overridable ReadOnly Property DataKey As DataKey

Property Value

DataKey

A DataKey object that represents the primary key of the displayed record.

Attributes: BrowsableAttribute

Examples

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") %> <%# 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>


<%@ Page language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
  
  Sub EmployeeFormView_ItemCreated(ByVal sender As Object, ByVal e As EventArgs)
  
    Dim key As DataKey = EmployeeFormView.DataKey
    MessageLabel.Text = "The key value is " & key.Value.ToString() & "."
  
  End Sub
    
</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") %> <%# 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>

Remarks

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.

Note

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

Applies to

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