ListViewUpdateEventArgs.Keys ListViewUpdateEventArgs.Keys ListViewUpdateEventArgs.Keys ListViewUpdateEventArgs.Keys Property

定義

更新する項目の主キーを表すフィールドの名前と値のペアのディクショナリを取得します。Gets a dictionary of field name/value pairs that represent the key or keys of the item to update.

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

プロパティ値

更新する項目の主キーを表すフィールドの名前と値のペア。The field name/value pairs that represent the key or keys of the item to update.

次の例は、 Keysプロパティを使用して、更新するレコードのキーフィールドの値にアクセスする方法を示しています。The following example shows how to use the Keys property to access the value of the key field for the record being updated.

重要

この例には、ユーザー入力を受け付けるテキスト ボックスがあります。これにより、セキュリティが脆弱になる可能性があります。This example has a text box that accepts user input, which is a potential security threat. 既定では、ASP.NET Web ページによって、ユーザー入力にスクリプトまたは HTML 要素が含まれていないかどうかが検証されます。By default, ASP.NET Web pages validate that user input does not include script or HTML elements. 詳細については、「スクリプトによる攻略の概要」を参照してください。For more information, see Script Exploits Overview.

<%@ 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 Page_Load()
  {
    Message.Text = String.Empty;
  }
    
  //<Snippet2>
  void UnitMeasureListView_ItemUpdating(Object sender, ListViewUpdateEventArgs e)
  {
    // Use the Keys property to retrieve the key field value
    String keyValue = e.Keys[0].ToString().Trim();

    // Cancel the update operation if the user attempts to 
    // edit a protected record. In this example, unit measure
    // codes with 3 letters are protected.
    if (keyValue.Length == 3)
    {
      Message.Text = "You cannot update this record. " +
        " Unit Measure Code " + keyValue + " is protected.";
        e.Cancel = true;
    }    
  }
  //</Snippet2>
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListViewUpdateEventArgs Keys Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewUpdateEventArgs Keys Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>

      <asp:ListView ID="UnitMeasureListView" 
        DataSourceID="UnitMeasureDataSource" 
        DataKeyNames="UnitMeasureCode"
        OnItemUpdating="UnitMeasureListView_ItemUpdating"  
        runat="server">
        <LayoutTemplate>
          <table width="400px" border="1" id="tblUnit">
            <tr runat="server">
              <th runat="server">&nbsp;</th>
              <th runat="server">Unit Measure Code</th>
              <th runat="server">Name</th>
            </tr>
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td>
              <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <AlternatingItemTemplate>
          <tr style="background-color:#B0C4DE" runat="server">
            <td>
              <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
          </tr>
        </AlternatingItemTemplate>
        <EditItemTemplate>
          <tr style="background-color:#4682B4">
            <td>
              <asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="Update" />
              <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:TextBox ID="NameTextBox" runat="server" Text='<%#Bind("Name") %>' MaxLength="50" /><br />
            </td>
          </tr>
        </EditItemTemplate>
      </asp:ListView>

      <!-- 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="UnitMeasureDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [UnitMeasureCode], [Name] FROM Production.UnitMeasure"
        UpdateCommand="UPDATE Production.UnitMeasure
                       SET [Name] = @Name
                       WHERE [UnitMeasureCode] = @UnitMeasureCode">
      </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 Page_Load() 
      Message.Text = String.Empty
  End Sub 'Page_Load

  Sub UnitMeasureListView_ItemUpdating(ByVal sender As Object, ByVal e As ListViewUpdateEventArgs)
    ' Use the Keys property to retrieve the key field value
    Dim keyValue As String = e.Keys(0).ToString().Trim()
    
    ' Cancel the update operation if the user attempts to 
    ' edit a protected record. In this example, unit measure
    ' codes with 3 letters are protected.
    If keyValue.Length = 3 Then
      Message.Text = "You cannot update this record. " & _
        " Unit Measure Code " & keyValue & " is protected."
      e.Cancel = True
    End If

  End Sub 'UnitMeasureListView_ItemUpdating

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListViewUpdateEventArgs Keys Example</title>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListViewUpdateEventArgs Keys Example</h3>
            
      <asp:Label ID="Message"
        ForeColor="Red"          
        runat="server"/>
      <br/>

      <asp:ListView ID="UnitMeasureListView" 
        DataSourceID="UnitMeasureDataSource" 
        DataKeyNames="UnitMeasureCode"
        OnItemUpdating="UnitMeasureListView_ItemUpdating"  
        runat="server">
        <LayoutTemplate>
          <table width="400px" border="1" id="tblUnit">
            <tr runat="server">
              <th runat="server">&nbsp;</th>
              <th runat="server">Unit Measure Code</th>
              <th runat="server">Name</th>
            </tr>
            <tr id="itemPlaceholder" runat="server"></tr>
          </table>
        </LayoutTemplate>
        <ItemTemplate>
          <tr runat="server">
            <td>
              <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
          </tr>
        </ItemTemplate>
        <AlternatingItemTemplate>
          <tr style="background-color:#B0C4DE" runat="server">
            <td>
              <asp:Button ID="EditButton" runat="server" CommandName="Edit" Text="Edit" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:Label ID="FirstNameLabel" runat="server" Text='<%#Eval("Name") %>' />
            </td>
          </tr>
        </AlternatingItemTemplate>
        <EditItemTemplate>
          <tr style="background-color:#4682B4">
            <td>
              <asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="Update" />
              <asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="Cancel" />
            </td>
            <td>
              <asp:Label ID="CodeLabel" runat="server" Text='<%#Eval("UnitMeasureCode") %>' />
            </td>
            <td>
              <asp:TextBox ID="NameTextBox" runat="server" Text='<%#Bind("Name") %>' MaxLength="50" /><br />
            </td>
          </tr>
        </EditItemTemplate>
      </asp:ListView>

      <!-- 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="UnitMeasureDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [UnitMeasureCode], [Name] FROM Production.UnitMeasure"
        UpdateCommand="UPDATE Production.UnitMeasure
                       SET [Name] = @Name
                       WHERE [UnitMeasureCode] = @UnitMeasureCode">
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

注釈

コントロールのプロパティが設定されている場合は、プロパティ(dictionary)を使用して、更新する項目の主キーの値にアクセスします。Keys DataKeyNames ListViewWhen the DataKeyNames property of a ListView control is set, use the Keys property (dictionary) to access the value of the primary key in the item to update.

注意

キー以外のフィールドの値にアクセスするには、 NewValuesプロパティまたはOldValuesプロパティを使用します。To access the values of the non-key fields, use the NewValues or OldValues properties. プロパティNewValuesは更新された値を格納OldValuesし、プロパティには元の値が格納されます。The NewValues property contains the updated values, and the OldValues property contains the original values.

ディクショナリには、 DataKeyNamesプロパティで指定されたフィールドの名前と値のペアが自動的に設定されます。 KeysThe Keys dictionary is automatically populated with the name/value pairs of the field or fields specified in the DataKeyNames property. 複数のフィールドが主キーを形成する場合は、キーフィールドごとKeysに個別のエントリがディクショナリに追加されます。If multiple fields form the primary key, a separate entry is added to the Keys dictionary for every key field.

キーフィールドの名前を確認するには、 DictionaryEntry.Key Keysディクショナリに格納さDictionaryEntryれているオブジェクトのプロパティを使用します。To determine the name of a key field, use the DictionaryEntry.Key property of a DictionaryEntry object that is contained in the Keys dictionary. キーフィールドの値を確認するには、 DictionaryEntry.Valueプロパティを使用します。To determine the value of a key field, use the DictionaryEntry.Value property.

適用対象

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