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DetailsViewModeEventHandler Delegate

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

Represents the method that handles the ModeChanging event of a DetailsView control.

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

public delegate void DetailsViewModeEventHandler (
	Object sender,
	DetailsViewModeEventArgs e
)
/** @delegate */
public delegate void DetailsViewModeEventHandler (
	Object sender, 
	DetailsViewModeEventArgs e
)
JScript supports the use of delegates, but not the declaration of new ones.

Parameters

sender

The source of the event.

e

A DetailsViewModeEventArgs that contains the event data.

The ModeChanging event is raised when a DetailsView control attempts to change between edit, insert, and read-only mode, but before the mode actually changes. This allows you to provide an event handler that performs a custom routine, such as configuring the DetailsView control for a specific mode or canceling the mode change, whenever this event occurs.

When you create a DetailsViewModeEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.

The following code example demonstrates how to programmatically add a DetailsViewModeEventHandler delegate to the ModeChanging event of a DetailsView control.


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

<script runat="server">

  void Page_Load(Object sender, EventArgs e)
  {

    // Create a new DetailsView object.
    DetailsView customerDetailsView = new DetailsView();

    // Set the DetailsView object's properties.
    customerDetailsView.ID = "CustomerDetailsView";
    customerDetailsView.DataSourceID = "DetailsViewSource";
    customerDetailsView.AutoGenerateRows = true;
    customerDetailsView.AutoGenerateEditButton = true;
    customerDetailsView.AllowPaging = true;
    customerDetailsView.DataKeyNames = new String[1] { "CustomerID" };

    // Programmatically register the event-handling method
    // for the ItemInserted event of a DetailsView control.
    customerDetailsView.ModeChanging += new DetailsViewModeEventHandler(this.CustomerDetailsView_ModeChanging);

    // Add the DetailsView object to the Controls collection
    // of the PlaceHolder control.
    DetailsViewPlaceHolder.Controls.Add(customerDetailsView);

  }
  
  void CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
  {

    // Use the sender parameter to access the DetailsView
    // control that raised the event.
    DetailsView customerDetailsView = (DetailsView)sender;

    // Use the NewMode property to determine the mode to which the 
    // DetailsView control is transitioning.
    switch (e.NewMode)
    {
      case DetailsViewMode.Edit:
        // Hide the pager row and clear the Label control
        // when transitioning to edit mode.
        customerDetailsView.AllowPaging = false;
        MessageLabel.Text = "";
        break;
      case DetailsViewMode.ReadOnly:
        // Display the pager row and confirmation message
        // when transitioning to edit mode.
        customerDetailsView.AllowPaging = true;
        if (e.CancelingEdit)
        {
          MessageLabel.Text = "Update canceled.";
        }
        else
        {
          MessageLabel.Text = "Update completed.";
        }
        break;
      case DetailsViewMode.Insert:
        // Cancel the mode change if the DetailsView
        // control attempts to transition to insert 
        // mode.
        e.Cancel = true;
        break;
      default:
        MessageLabel.Text = "Unsupported mode.";
        break;
    }
    
  }

</script>

<html>
  <body>
    <form runat="server">
        
      <h3>DetailsViewModeEventHandler Example</h3>
      
      <!-- Use a PlaceHolder control as the container for the -->
      <!-- dynamically generated DetailsView control.         -->       
      <asp:PlaceHolder id="DetailsViewPlaceHolder"
        runat="server"/>
        
      <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="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>


The following code example demonstrates how to declaratively add a DetailsViewModeEventHandler delegate to the ModeChanging event of a DetailsView control.


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

<script runat="server">

  void CustomerDetailsView_ModeChanging(Object sender, DetailsViewModeEventArgs e)
  {

    // Use the NewMode property to determine the mode to which the 
    // DetailsView control is transitioning.
    switch (e.NewMode)
    {
      case DetailsViewMode.Edit:
        // Hide the pager row and clear the Label control
        // when transitioning to edit mode.
        CustomerDetailsView.AllowPaging = false;
        MessageLabel.Text = "";
        break;
      case DetailsViewMode.ReadOnly:
        // Display the pager row and confirmation message
        // when transitioning to edit mode.
        CustomerDetailsView.AllowPaging = true;
        if (e.CancelingEdit)
        {
          MessageLabel.Text = "Update canceled.";
        }
        else
        {
          MessageLabel.Text = "Update completed.";
        }
        break;
      case DetailsViewMode.Insert:
        // Cancel the mode change if the DetailsView
        // control attempts to transition to insert 
        // mode.
        e.Cancel = true;
        break;
      default:
        MessageLabel.Text = "Unsupported mode.";
        break;
    }
    
  }

</script>

<html>
  <body>
    <form runat="server">
        
      <h3>DetailsViewModeEventHandler Example</h3>
                
      <asp:detailsview id="CustomerDetailsView"
        datasourceid="DetailsViewSource"
        datakeynames="CustomerID"
        autogeneraterows="true"
        autogenerateeditbutton="true" 
        allowpaging="true"
        onmodechanging="CustomerDetailsView_ModeChanging" 
        runat="server">

      </asp:detailsview>
      
      <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="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>


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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