DataKeyArray.Item[Int32] プロパティ

定義

指定されたインデックス位置にある DataKey オブジェクトをコレクションから取得します。Gets the DataKey object from the collection at the specified index.

public:
 property System::Web::UI::WebControls::DataKey ^ default[int] { System::Web::UI::WebControls::DataKey ^ get(int index); };
public System.Web.UI.WebControls.DataKey this[int index] { get; }
member this.Item(int) : System.Web.UI.WebControls.DataKey
Default Public ReadOnly Property Item(index As Integer) As DataKey

パラメーター

index
Int32

コレクションから取得する DataKey のインデックス。The index of the DataKey to retrieve from the collection.

プロパティ値

コレクション内の指定したインデックス位置の DataKeyThe DataKey at the specified index in the collection.

次のコード例は、インデクサーを使用してDataKey DataKeyArrayコレクションからオブジェクトを取得する方法を示しています。The following code example demonstrates how to use the indexer to retrieve a DataKey object from a DataKeyArray collection.


<%@ 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 CustomerGridView_DataBound(Object sender, EventArgs e)
  {           
    // Use the indexer to retrieve the DataKey object for the 
    // first record.
    DataKey key = CustomerGridView.DataKeys[0];

    // Display the value of the primary key for the first
    // record displayed in the GridView control.
    MessageLabel.Text = "The primary key of the first record displayed is " +
      key.Value.ToString() + ".";
  }

  void CopyArray_Click(Object sender, EventArgs e)
  {
      DataKeyArray theKeys = CustomerGridView.DataKeys;
      DataKey[] myNewArray = new DataKey[theKeys.Count];
      theKeys.CopyTo(myNewArray, 0);
      Label2.Visible = true;

      // Display first page key values from the new array.
      for (int i = 0; i < myNewArray.Length; i++)
      {
          Label2.Text += "<br />" + myNewArray[i].Value;
      }

  }

</script>

<html  >

  <head id="Head1" runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">

      <h3>DataKeyArray Example</h3>

        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          ondatabound="CustomerGridView_DataBound" 
          runat="server">

        </asp:gridview>

        <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="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthwindConnectionString %>" 
          runat="server"/>

        <asp:Button ID="CopyArray" 
            runat="server" 
            Text="Copy DataKeyArray to Array" 
            OnClick="CopyArray_Click" />

        <br />

        <asp:label id="Label2"
          runat="server"
          Visible="false"  
          Text="First page of Copied Array Key Values" />


      </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 CustomerGridView_DataBound(ByVal sender As Object, ByVal e As EventArgs) Handles CustomerGridView.DataBound
          
    ' Use the indexer to retrieve the DataKey object for the 
    ' first record.
    Dim key As DataKey = CustomerGridView.DataKeys(0)

    ' Display the value of the primary key for the first
    ' record displayed in the GridView control.
    MessageLabel.Text = "The primary key of the first record displayed is " & _
      key.Value.ToString() & "."
  
    End Sub
    
    Sub CopyArray_Click(ByVal sender As Object, ByVal e As EventArgs)
        Dim theKeys As DataKeyArray = CustomerGridView.DataKeys
        Dim myNewArray(theKeys.Count - 1) As DataKey
        theKeys.CopyTo(myNewArray, 0)
        Label2.Visible = True

        ' Display first page key values from the new array.  
        For i As Integer = 0 To myNewArray.Length - 1
            Label2.Text &= "<br />" & myNewArray(i).Value
        Next i

    End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head id="Head1" runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          runat="server">
            
        </asp:gridview>
        
        <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="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>

        <asp:Button ID="CopyArray" 
            runat="server" 
            Text="Copy DataKeyArray to Array" 
            OnClick="CopyArray_Click" />

        <br />

        <asp:label id="Label2"
          runat="server"
          Visible="false"  
          Text="First page of Copied Array Key Values" />
            
      </form>
  </body>
</html>

注釈

このインデクサーを使用してDataKey 、配列表記を使用して、指定したインデックス位置にあるコレクションからオブジェクトを取得します。Use this indexer to retrieve a DataKey object from the collection at the specified index, using array notation. このプロパティは読み取り専用です。This property is read-only.

適用対象

こちらもご覧ください