ListViewDeletedEventArgs.Keys Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.Extensions.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 the key or keys for the deleted item.

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

The key or keys for the deleted item.

Examples

The following example shows how to use the Keys property to access the values of the key fields for a deleted item.

<%@ 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 ContactsListView_ItemDeleted(Object sender, ListViewDeletedEventArgs e)
  {
    // Display the value of the key fields in the Keys property.
    KeysMessageLabel.Text =
      "The key fields for the deleted record are: <br/>";

    foreach (DictionaryEntry entry in e.Keys)
    {
      DisplayValue(entry, KeysMessageLabel);
    }

    // Display the value of the non-key fields in the Values 
    // property.
    ValuesMessageLabel.Text =
      "The non-key fields for the deleted record are: <br/>";

    foreach (DictionaryEntry entry in e.Values)
    {
      DisplayValue(entry, ValuesMessageLabel);
    }

  }

  void DisplayValue(DictionaryEntry entry, Label displayLabel)
  {
    // Display the field name contained in the DictionaryEntry object.
    if (entry.Key != null)
    {
      displayLabel.Text += "Name=" + entry.Key.ToString() + ", ";
    }
    else
    {
      displayLabel.Text += "Name=null, ";
    }

    // Display the field value contained in the DictionaryEntry object.
    if (entry.Value != null)
    {
      displayLabel.Text += "Value=" + entry.Value.ToString() + "<br/>";
    }
    else
    {
      displayLabel.Text += "Value=null<br/>";
    }
  }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>ListViewDeletedEventArgs Keys and Values Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewDeletedEventArgs Keys and Values Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
                
      <br/>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"  
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblContacts" width="640px">
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|<< " LastPageText=" >>|"
                NextPageText=" > " PreviousPageText=" < " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Bind("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Bind("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Bind("EmailAddress") %>' />
            </td>
            <td>
              <asp:LinkButton ID="DeleteButton" runat="server" 
                CommandName="Delete" 
                Text="Delete" 
                OnClientClick="return confirm('Are you sure?');" />
            </td>
          </tr>
        </ItemTemplate>
      </asp:ListView>
                 
      <br/><br />
         
      <asp:Label ID="KeysMessageLabel"
        ForeColor="Red"
        runat="server"/>
          
      <br/>
          
      <asp:Label ID="ValuesMessageLabel"
        ForeColor="Red"
        runat="server"/>
            
      <!-- This example uses Microsoft SQL Server and connects    -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET  -->
      <!-- expression to retrieve the connection string value     -->
      <!-- from the Web.config file.                              -->            
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] FROM Person.Contact"
        DeleteCommand="DELETE FROM Person.Contact WHERE [ContactID] = @ContactID">
          <DeleteParameters>
              <asp:Parameter Name="ContactID" Type="Int32" />
          </DeleteParameters>
      </asp:SqlDataSource>

    </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 ContactsListView_ItemDeleted(sender As Object, e As ListViewDeletedEventArgs)

    ' Display the value of the key fields in the Keys property.
    KeysMessageLabel.Text = _
      "The key fields for the deleted record are: <br/>"

    For Each entry As DictionaryEntry In e.Keys
      DisplayValue(entry, KeysMessageLabel)
    Next

    ' Display the value of the non-key fields in the Values 
    ' property.
    ValuesMessageLabel.Text = _
      "The non-key fields for the deleted record are: <br/>"

    For Each entry As DictionaryEntry In e.Values
      DisplayValue(entry, ValuesMessageLabel)
    Next
  End Sub

  Sub DisplayValue(entry As DictionaryEntry, displayLabel As Label)

    ' Display the field name contained in the DictionaryEntry object.
    If entry.Key IsNot Nothing Then
      displayLabel.Text &= "Name=" & entry.Key.ToString() & ", "
    Else
      displayLabel.Text &= "Name=null, "
    End If

    ' Display the field value contained in the DictionaryEntry object.
    If entry.Value IsNot Nothing
      displayLabel.Text &= "Value=" & entry.Value.ToString() & "<br/>"
    else
      displayLabel.Text &= "Value=null<br/>"
    End If
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListViewDeletedEventArgs Keys and Values Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewDeletedEventArgs Keys and Values Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
                
      <br/>
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        DataKeyNames="ContactID"
        OnItemDeleted="ContactsListView_ItemDeleted"  
        runat="server">
        <LayoutTemplate>
          <table cellpadding="2" runat="server" id="tblContacts" width="640px">
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
          <asp:DataPager runat="server" ID="PeopleDataPager" PageSize="12">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|<< " LastPageText=" >>|"
                NextPageText=" > " PreviousPageText=" < " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td valign="top">
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Bind("FirstName") %>' />
              <asp:Label ID="LastNameLabel" runat="server" Text='<%#Bind("LastName") %>' />
            </td>
            <td>
              <asp:Label ID="EmailLabel" runat="server" Text='<%#Bind("EmailAddress") %>' />
            </td>
            <td>
              <asp:LinkButton ID="DeleteButton" runat="server" 
                CommandName="Delete" 
                Text="Delete" 
                OnClientClick="return confirm('Are you sure?');" />
            </td>
          </tr>
        </ItemTemplate>
      </asp:ListView>
                 
      <br/><br />
         
      <asp:Label ID="KeysMessageLabel"
        ForeColor="Red"
        runat="server"/>
          
      <br/>
          
      <asp:Label ID="ValuesMessageLabel"
        ForeColor="Red"
        runat="server"/>
            
      <!-- This example uses Microsoft SQL Server and connects    -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET  -->
      <!-- expression to retrieve the connection string value     -->
      <!-- from the Web.config file.                              -->            
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName], [EmailAddress] FROM Person.Contact"
        DeleteCommand="DELETE FROM Person.Contact WHERE [ContactID] = @ContactID">
          <DeleteParameters>
              <asp:Parameter Name="ContactID" Type="Int32" />
          </DeleteParameters>
      </asp:SqlDataSource>

    </form>
  </body>
</html>

Remarks

Use the Keys property to access the values of the key fields (as specified by the ListView.DataKeyNames property) for a deleted item. For example, you can use these values to keep a log of deleted items.

Note

This property contains only the key fields. To access 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 of the deleted item.

Applies to