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DetailsViewDeleteEventArgs.Keys Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Gets an ordered dictionary of key field name/value pairs that contains the names and values of the key fields of the deleted items.

public:
 property System::Collections::Specialized::IOrderedDictionary ^ Keys { System::Collections::Specialized::IOrderedDictionary ^ get(); };
public System.Collections.Specialized.IOrderedDictionary Keys { get; }
member this.Keys : System.Collections.Specialized.IOrderedDictionary
Public ReadOnly Property Keys As IOrderedDictionary

Property Value

IOrderedDictionary

An IOrderedDictionary that contains an ordered dictionary of key field name/value pairs used to match the item to delete.

Examples

The following code example demonstrates how to use the Keys property to access the value of the key field for the record being deleted.


<%@ 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 CustomerDetailsView_ItemDeleting(Object sender, 
    DetailsViewDeleteEventArgs e)
  {

    // Get customer ID and name from the Keys and Values
    // properties.
    String keyValue = e.Keys["CustomerID"].ToString();
    String customerName = e.Values["CompanyName"].ToString();

    // Cancel the delete operation if the user attempts to 
    // delete protected record. In this example, records
    // with a customer ID that starts with with "A" cannot
    // be deleted.
    if (keyValue.StartsWith("A"))
    {
      e.Cancel = true;
      MessageLabel.Text = "You cannot delete " +
        customerName + ". This customer is protected.";
    }
    else
    {
      MessageLabel.Text = "Row " + e.RowIndex.ToString() + 
        " deleted.";
    }

  }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewDeleteEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewDeleteEventArgs Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogeneratedeletebutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          onitemdeleting="CustomerDetailsView_ItemDeleting" 
          runat="server">
            
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <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]"
          deletecommand="Delete [Customers] 
            Where [CustomerID]=@CustomerID"
          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 CustomerDetailsView_ItemDeleting(ByVal sender As Object, _
    ByVal e As DetailsViewDeleteEventArgs)

    ' Get customer ID and name from the Keys and Values
    ' properties.
    Dim keyValue As String = e.Keys("CustomerID").ToString()
    Dim customerName As String = e.Values("CompanyName").ToString()

    ' Cancel the delete operation if the user attempts to 
    ' delete protected record. In this example, records
    ' with a customer ID that starts with with "A" cannot
    ' be deleted.
    If keyValue.StartsWith("A") Then

      e.Cancel = True
      MessageLabel.Text = "You cannot delete " & _
        customerName & ". This customer is protected."
    
    Else
    
      MessageLabel.Text = "Row " & e.RowIndex.ToString() & _
        " deleted."
    
    End If
    
  End Sub

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>DetailsViewDeleteEventArgs Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DetailsViewDeleteEventArgs Example</h3>
                
        <asp:detailsview id="CustomerDetailsView"
          datasourceid="DetailsViewSource"
          datakeynames="CustomerID"
          autogeneratedeletebutton="true"  
          autogeneraterows="true"
          allowpaging="true"
          onitemdeleting="CustomerDetailsView_ItemDeleting" 
          runat="server">
            
          <fieldheaderstyle backcolor="Navy"
            forecolor="White"/>
                    
        </asp:detailsview>
        
        <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]"
          deletecommand="Delete [Customers] 
            Where [CustomerID]=@CustomerID"
          connectionstring=
            "<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

Remarks

Use the Keys property to access the values of the key field or fields for the record to be deleted. For example, you can use these values to verify the record before deleting it, to change the record to delete, or to keep a log of deleted records.

Note

This property contains only the key fields. To access the name/value pair values for the non-key fields, use the Values property.

The Keys property returns an object that implements the IOrderedDictionary interface. The object contains DictionaryEntry objects that represent the key fields.

Note

As a shortcut, you can also use the indexer of the IOrderedDictionary object to access the key field values. The advantage in using the indexer is that it returns key field values directly.

This property is read-only; however, you can modify the key field values of the IOrderedDictionary object it returns. If you change the key field values, the corresponding record is be deleted from the data source.

Applies to

See also