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DetailsViewUpdateEventArgs Class
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DetailsViewUpdateEventArgs Class

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

Provides data for the ItemUpdating event.

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

'Declaration
Public Class DetailsViewUpdateEventArgs
	Inherits CancelEventArgs
'Usage
Dim instance As DetailsViewUpdateEventArgs

public class DetailsViewUpdateEventArgs extends CancelEventArgs
public class DetailsViewUpdateEventArgs extends CancelEventArgs

The DetailsView control raises the ItemUpdating event when an Update button (a button with its CommandName property set to "Update") within the control is clicked, but before the DetailsView control updates the record. This allows you to provide an event handler that performs a custom routine, such as HTML-encoding the values of a record before updating it in the data source, whenever this event occurs.

A DetailsViewUpdateEventArgs object is passed to the event handler, which allows you to determine the value of an optional command argument sent to the DetailsView control and to indicate whether the update operation should be canceled. To determine the value of the command argument, use the CommandArgument property. To cancel the update operation, set the Cancel property to true. You can also read or modify the new values entered by the user by using the Keys and NewValues properties. The Keys property contains the key fields, while the NewValues property contains the non-key fields. If you need to access the original non-key field values, use the OldValues property.

For more information about handling events, see Consuming Events.

For a list of initial property values for an instance of the DetailsViewUpdateEventArgs class, see the DetailsViewUpdateEventArgs constructor.

The following code example demonstrates how to use the DetailsViewUpdateEventArgs object passed to the event handler for the ItemUpdating event to validate the values entered by the user.


<%@ Page language="VB" %>

<script runat="server">
  
  Sub CustomerDetailsView_ItemUpdating(ByVal sender As Object, _
    ByVal e As DetailsViewUpdateEventArgs)

    ' Validate the field values entered by the user. This
    ' example determines whether the user left any fields
    ' empty. Use the NewValues property to access the new 
    ' values entered by the user.
    Dim emptyFieldList As ArrayList = _
      ValidateFields(CType(e.NewValues, IOrderedDictionary))

    If emptyFieldList.Count > 0 Then

      ' The user left some fields empty. Display an error message.
      
      ' Use the Keys property to retrieve the key field value.
      Dim keyValue As String = e.Keys("CustomerID").ToString()

      MessageLabel.Text = _
        "You must enter a value for all fields of record " & _
        keyValue & ".<br/>The following fields are missing:<br/><br/>"

      ' Display the missing fields.
      Dim value As String
      For Each value In emptyFieldList
      
        ' Use the OldValues property access the original value
        ' of a field.
        MessageLabel.Text &= value & " - Original Value = " & _
          e.OldValues(value).ToString() & "<br>"
        
      Next

      ' Cancel the update operation.
      e.Cancel = True

    Else
    
      ' The field values passed validation. Clear the
      ' error message label.
      MessageLabel.Text = ""
      
    End If

  End Sub

    Function ValidateFields(ByVal list As IOrderedDictionary) _
      As ArrayList
    
        ' Create an ArrayList object to store the
        ' names of any empty fields.
        Dim emptyFieldList As New ArrayList()

        ' Iterate though the field values entered by
        ' the user and check for an empty field. Empty
        ' fields contain a null value.
        Dim entry As DictionaryEntry
    
        For Each entry In list
    
            If entry.Value Is Nothing Then
      
                ' Add the field name to the ArrayList object.
                emptyFieldList.Add(entry.Key.ToString())
        
            End If
        Next

        Return emptyFieldList
  
    End Function

  Sub CustomerDetailsView_ModeChanging(ByVal sender As Object, ByVal e As DetailsViewModeEventArgs)
  
    If e.CancelingEdit Then
      
      ' The user canceled the update operation.
      ' Clear the error message label.
      MessageLabel.Text = ""
    
    End If
    
  End Sub

</script>

<html>

  <body>
    <form runat="server">
        
      <h3>DetailsViewUpdateEventArgs Example</h3>
                       
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          autogeneraterows="true"
          autogenerateeditbutton="true"  
          allowpaging="true"
          datakeynames="CustomerID" 
          onitemupdating="CustomerDetailsView_ItemUpdating"
          onmodechanging="CustomerDetailsView_ModeChanging" 
          runat="server">
            
          <pagersettings position="Bottom"/> 
                    
        </asp:detailsview>
        
        <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="DetailsViewSource"
          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"
          connectionstring=
          "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>


System.Object
   System.EventArgs
     System.ComponentModel.CancelEventArgs
      System.Web.UI.WebControls.DetailsViewUpdateEventArgs

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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.

.NET Framework

Supported in: 2.0

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