GridView.DataKeyNames Property (System.Web.UI.WebControls)

DataKeyNames Property

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Microsoft Visual Studio 2005/.NET Framework 2.0

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.NET Framework Class Library

GridView.DataKeyNames Property

Note: This property is new in the .NET Framework version 2.0.

Gets or sets an array that contains the names of the primary key fields for the items displayed in a GridView control.

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

Syntax

Visual Basic (Declaration)

Public Overridable Property DataKeyNames As String()

Visual Basic (Usage)

Dim instance As GridView
Dim value As String()

value = instance.DataKeyNames

instance.DataKeyNames = value

public virtual string[] DataKeyNames { get; set; }

C++

public:
virtual property array<String^>^ DataKeyNames {
    array<String^>^ get ();
    void set (array<String^>^ value);
}

/** @property */
public String[] get_DataKeyNames ()

/** @property */
public void set_DataKeyNames (String[] value)

JScript

public function get DataKeyNames () : String[]

public function set DataKeyNames (value : String[])

Property Value

An array that contains the names of the primary key fields for the items displayed in a GridView control.

Remarks

Use the DataKeyNames property to specify the field or fields that represent the primary key of the data source.

Note
To set this property declaratively, use a comma-separated list of field names.

When the DataKeyNames property is set, the GridView control automatically populates its DataKeys collection with the values from the specified field or fields, which provides a convenient way to access the primary keys of each row.

Note
The GridView control stores these key field values in the control state. If these values contain sensitive information, it is strongly recommended that you enable view-state encryption by setting the ViewStateEncryptionMode property to ViewStateEncryptionMode.Always.

When using automatically generated field columns (by setting the AutoGenerateColumns property to true), the GridView control automatically ensures that the automatically generated field columns that correspond to the field or fields specified in the DataKeyNames property are read-only.

Note
You must set the DataKeyNames property for the automatic updating and deleting features of the GridView control to work. The values of these key fields are passed to the data source control in order to match the row to update or delete.

If the Visible property of a column field is set to false, the column is not displayed in the GridView control and the data for the column does not make a round trip to the client. If you want the data for a column that is not visible to make a round trip, add the field name to the DataKeyNames property.

Topic	Location
Walkthrough: Creating a Web Page to Display XML Data	Building ASP .NET Web Applications in Visual Studio
Walkthrough: Creating a Web Page to Display XML Data	Building ASP .NET Web Applications in Visual Studio
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Walkthrough: Displaying an XML Document in a Web Forms Page Using Transformations	Building ASP .NET Web Applications in Visual Studio

Example

The following code example demonstrates how to use the DataKeyNames property to specify the key field of the data source.

Visual Basic

<%@ Page language="VB" %>

<html>
  <body>
    <form runat="server">
        
      <h3>GridView Edit Example</h3>

      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogeneratedeletebutton="true"
        autogenerateeditbutton="true"
        datakeynames="CustomerID"  
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        deletecommand="Delete from Customers where CustomerID = @CustomerID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

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

<html>
  <body>
    <form runat="server">
        
      <h3>GridView Edit Example</h3>

      <!-- The GridView control automatically sets the columns     -->
      <!-- specified in the datakeynames property as read-only.    -->
      <!-- No input controls are rendered for these columns in     -->
      <!-- edit mode.                                              -->
      <asp:gridview id="CustomersGridView" 
        datasourceid="CustomersSqlDataSource" 
        autogeneratecolumns="true"
        autogeneratedeletebutton="true"
        autogenerateeditbutton="true"
        datakeynames="CustomerID"  
        runat="server">
      </asp:gridview>
            
      <!-- 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="CustomersSqlDataSource"  
        selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
        updatecommand="Update Customers SET CompanyName=@CompanyName, Address=@Address, City=@City, PostalCode=@PostalCode, Country=@Country WHERE (CustomerID = @CustomerID)"
        deletecommand="Delete from Customers where CustomerID = @CustomerID"
        connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Platforms

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

Version Information

.NET Framework

Supported in: 2.0

Reference

GridView Class
GridView Members
System.Web.UI.WebControls Namespace
DataKey Class
DataKeyArray Class
GridView.AutoGenerateEditButton Property
GridView.AutoGenerateDeleteButton Property
DataKeys

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