DataGrid.OnItemDataBound メソッドとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

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DataGrid.OnItemDataBound メソッド

ItemDataBound イベントを発生させます。この機能により、イベントのカスタムハンドラを作成できます。

名前空間: System.Web.UI.WebControls
アセンブリ: System.Web (system.web.dll 内)
構文

Visual Basic (宣言)

Protected Overridable Sub
 OnItemDataBound ( _
    e As DataGridItemEventArgs _
)

Visual Basic (使用法)

Dim e As DataGridItemEventArgs

Me.OnItemDataBound(e)

protected virtual void OnItemDataBound (
    DataGridItemEventArgs e
)

C++

protected:
virtual void OnItemDataBound (
    DataGridItemEventArgs^ e
)

protected void OnItemDataBound (
    DataGridItemEventArgs e
)

JScript

protected function OnItemDataBound (
    e : DataGridItemEventArgs
)

パラメータ

e: イベントデータを格納している DataGridItemEventArgs。

解説

OnItemDataBound メソッドを使用して ItemDataBound イベントのカスタムハンドラを提供します。

ItemDataBound イベントは、項目が DataGrid コントロールにデータ連結された後に発生します。このイベントは、クライアント上にデータ項目が表示される前に、その項目にアクセスする最後の機会を提供します。このイベントが発生した後は、データ項目が null になり、使用できなくなります。

イベントが発生すると、デリゲートを使用してイベントハンドラが呼び出されます。詳細については、「イベントの発生」を参照してください。

継承時の注意 派生クラスで OnItemDataBound をオーバーライドする場合は、基本クラスの OnItemDataBound メソッドを呼び出してください。イベント処理の詳細については、「イベントの利用」を参照してください。

使用例

ItemDataBound イベントのハンドラを指定およびコーディングして、DataGrid の項目がデータ連結された順序を表示する方法を次の例に示します。

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True"
 %>
<%@ Import Namespace="System.Data"
 %>
 
<html>
<script language="VB" runat="server">
 
    Dim Cart As DataTable
    Dim CartView As DataView
    Function CreateDataSource() As ICollection
        Dim dt As New DataTable()
        Dim dr As DataRow
        
        dt.Columns.Add(New DataColumn("IntegerValue",
 GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue",
 GetType(String)))
        dt.Columns.Add(New DataColumn("CurrencyValue",
 GetType(Double)))
        
        Dim i As Integer
        For i = 0 To 9
            dr = dt.NewRow()
            
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 *(i + 1)
            
            dt.Rows.Add(dr)
        Next i
        
        Dim dv As New DataView(dt)
        Return dv
    End Function 'CreateDataSource


    Sub Page_Load(sender As Object,
 e As EventArgs)
        
        If Not IsPostBack Then
            ' Need to load this data only once.
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
        End If
    End Sub 'Page_Load
     

    Sub Item_Bound(sender As Object,
 e As DataGridItemEventArgs)
        
        Label1.Text = Label1.Text & " " &
 e.Item.ItemIndex
    End Sub 'Item_Bound 
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true"
           OnItemDataBound="Item_Bound"
           AutoGenerateColumns="true">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>
 
      <br>
 
      <asp:Label id="Label1" 
           Text="Order of items data bound: " 
           runat="server"/>

      <br>

      <asp:Label id="Label2" 
           Text="Note: The -1's refer to the header and footer."
 
           runat="server"/>
 
   </form>
 
</body>
</html>

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
<script language="C#" runat="server">
 
   DataTable Cart;
   DataView CartView;
 
   ICollection CreateDataSource() 
   {
      DataTable dt = new DataTable();
      DataRow dr;
 
      dt.Columns.Add(new DataColumn("IntegerValue",
 typeof(Int32)));
      dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
      dt.Columns.Add(new DataColumn("CurrencyValue",
 typeof(double)));
 
      for (int i = 0; i < 10; i++) 
      {
         dr = dt.NewRow();
 
         dr[0] = i;
         dr[1] = "Item " + i.ToString();
         dr[2] = 1.23 * (i+1);
 
         dt.Rows.Add(dr);
      }
 
      DataView dv = new DataView(dt);
      return dv;
   }
 
   void Page_Load(Object sender, EventArgs e) 
   {
 
      if (!IsPostBack) 
      {
         // Need to load this data only once.
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();
      }
 
   }
 
   void Item_Bound(Object sender, DataGridItemEventArgs e) 
   {
 
      Label1.Text = Label1.Text + " " + e.Item.ItemIndex;
 
   }
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true"
           OnItemDataBound="Item_Bound"
           AutoGenerateColumns="true">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>
 
      <br>
 
      <asp:Label id="Label1" 
           Text="Order of items data bound: " 
           runat="server"/>

      <br>

      <asp:Label id="Label2" 
           Text="Note: The -1's refer to the header and footer." 
           runat="server"/>
 
   </form>
 
</body>
</html>

JScript

<%@ Page Language="JScript" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
<script language="JScript" runat="server">
 
      var Cart : DataTable;
      var CartView : DataView;
 
      function CreateDataSource() : ICollection 
      {
       
         var dt : DataTable = new DataTable();
         var dr : DataRow;
 
         dt.Columns.Add(new DataColumn("IntegerValue",
 Int32));
         dt.Columns.Add(new DataColumn("StringValue",
 System.String));
         dt.Columns.Add(new DataColumn("CurrencyValue",
 double));
 
         for (var i : int
 = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i+1);
 
            dt.Rows.Add(dr);
         }
 
         var dv : DataView = new DataView(dt);
         return dv;
      }
 

   function Page_Load(sender, e : EventArgs) 
   {
 
      if (!IsPostBack) 
      {
         // Need to load this data only once.
         ItemsGrid.DataSource = CreateDataSource();
         ItemsGrid.DataBind();
      }
 
   }
 
   function Item_Bound(sender, e : DataGridItemEventArgs) 
   {
 
      Label1.Text = Label1.Text + " " + e.Item.ItemIndex;
 
   }
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true"
           OnItemDataBound="Item_Bound"
           AutoGenerateColumns="true">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>
 
      <br>
 
      <asp:Label id="Label1" 
           Text="Order of items data bound: " 
           runat="server"/>

      <br>

      <asp:Label id="Label2" 
           Text="Note: The -1's refer to the header and footer." 
           runat="server"/>
 
   </form>
 
</body>
</html>

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True"
 %>
<%@ Import Namespace="System.Data"
 %>
 
<html>
   <script runat="server">
 
      Function CreateDataSource() As ICollection

         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New
 DataTable()
         Dim dr As DataRow 
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue",
 GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue",
 GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue",
 GetType(Double)))
 
         ' Populate the table with sample values.
         Dim i As Integer
         

         For i=0 To 10 

            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)
         
         Next i
 
         Dim dv As DataView = New
 DataView(dt)

         return dv
      
      End Function
 
      Sub Page_Load(sender As Object,
 e As EventArgs)
 
         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then
         
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
         
         End If

      End Sub
 
      Sub Item_Bound(sender As Object,
 e As DataGridItemEventArgs) 
 
         ' Use the ItemDataBound event to customize the DataGrid control.
 
         ' The ItemDataBound event allows you to access the data before
 
         ' the item is displayed in the control. In this example, the
 
         ' ItemDataBound event is used to format the items in the 
         ' CurrencyColumn in currency format.
         If e.Item.ItemType = ListItemType.Item Or
 _
             e.Item.ItemType = ListItemType.AlternatingItem Then
 
            ' Retrieve the text of the CurrencyColumn from the DataGridItem
            ' and convert the value to a Double.
            Dim Price As Double
 = Convert.ToDouble(e.Item.Cells(2).Text)

            ' Format the value as currency and redisplay it in the DataGrid.
            e.Item.Cells(2).Text = Price.ToString("c")
        
         End If         
 
      End Sub
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true"
           OnItemDataBound="Item_Bound">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>

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

<%@ Page Language="C#" AutoEventWireup="True" Debug="true"
 %>
<%@ Import Namespace="System.Data" %>
 
<html>
   <script runat="server">
 
      ICollection CreateDataSource()
      {

         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue",
 typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue",
 typeof(String)));
         dt.Columns.Add(new DataColumn("CurrencyValue",
 typeof(Double)));
 
         // Populate the table with sample values.
         for (int i=0; i<=10; i++) 
         {

            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         
         }
 
         DataView dv = new DataView(dt);

         return dv;
      
      }
 
      void Page_Load(Object sender, EventArgs e)
      { 
 
         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack)
         { 
         
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
         
         }

      }
 
      void Item_Bound(Object sender, DataGridItemEventArgs e)
 
      {
 
         // Use the ItemDataBound event to customize the DataGrid control.
 
         // The ItemDataBound event allows you to access the data before
 
         // the item is displayed in the control. In this example, the
 
         // ItemDataBound event is used to format the items in the 
         // CurrencyColumn in currency format.
         if((e.Item.ItemType == ListItemType.Item) || 
             (e.Item.ItemType == ListItemType.AlternatingItem))
         {
 
            // Retrieve the text of the CurrencyColumn from the DataGridItem
            // and convert the value to a Double.
            Double Price = Convert.ToDouble(e.Item.Cells[2].Text);

            // Format the value as currency and redisplay it in the
 DataGrid.
            e.Item.Cells[2].Text = Price.ToString("c");
        
         }         
 
      }
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true"
           OnItemDataBound="Item_Bound">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>

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

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True"
 %>
<%@ Import Namespace="System.Data"
 %>
 
<html>
   <script runat="server">
 
      Function CreateDataSource() As ICollection

         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New
 DataTable()
         Dim dr As DataRow 
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue",
 GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue",
 GetType(String)))
         dt.Columns.Add(New DataColumn("CurrencyValue",
 GetType(Double)))
 
         ' Populate the table with sample values.
         Dim i As Integer
         

         For i=0 To 10 

            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)
         
         Next i
 
         Dim dv As DataView = New
 DataView(dt)

         return dv
      
      End Function
 
      Sub Page_Load(sender As Object,
 e As EventArgs)

         ' Manually register the event-handling method for the  
         ' ItemDataBound event of the DataGrid control.
         AddHandler ItemsGrid.ItemDataBound, AddressOf
 Item_Bound
 
         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then
         
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
         
         End If

      End Sub
 
      Sub Item_Bound(sender As Object,
 e As DataGridItemEventArgs) 
 
         ' Use the ItemDataBound event to customize the DataGrid control.
 
         ' The ItemDataBound event allows you to access the data before
 
         ' the item is displayed in the control. In this example, the
 
         ' ItemDataBound event is used to format the items in the 
         ' CurrencyColumn in currency format.
         If e.Item.ItemType = ListItemType.Item Or
 _
             e.Item.ItemType = ListItemType.AlternatingItem Then
 
            ' Retrieve the text of the CurrencyColumn from the DataGridItem
            ' and convert the value to a Double.
            Dim Price As Double
 = Convert.ToDouble(e.Item.Cells(2).Text)

            ' Format the value as currency and redisplay it in the DataGrid.
            e.Item.Cells(2).Text = Price.ToString("c")
        
         End If         
 
      End Sub
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>

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

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<html>
   <script runat="server">
 
      ICollection CreateDataSource()
      {

         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue",
 typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue",
 typeof(String)));
         dt.Columns.Add(new DataColumn("CurrencyValue",
 typeof(Double)));
 
         // Populate the table with sample values.
         for (int i=0; i<=10; i++) 
         {

            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         
         }
 
         DataView dv = new DataView(dt);

         return dv;
      
      }
 
      void Page_Load(Object sender, EventArgs e)
      { 
 
         // Manually register the event-handling method for the  
         // ItemDataBound event of the DataGrid control.
         ItemsGrid.ItemDataBound += 
             new DataGridItemEventHandler(this.Item_Bound);

         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack)
         { 
         
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
         
         }

      }
 
      void Item_Bound(Object sender, DataGridItemEventArgs e)
 
      {
 
         // Use the ItemDataBound event to customize the DataGrid control.
 
         // The ItemDataBound event allows you to access the data before
 
         // the item is displayed in the control. In this example, the
 
         // ItemDataBound event is used to format the items in the 
         // CurrencyColumn in currency format.
         if((e.Item.ItemType == ListItemType.Item) ||
             (e.Item.ItemType == ListItemType.AlternatingItem))
         {
 
            // Retrieve the text of the CurrencyColumn from the DataGridItem
            // and convert the value to a Double.
            Double Price = Convert.ToDouble(e.Item.Cells[2].Text);

            // Format the value as currency and redisplay it in the
 DataGrid.
            e.Item.Cells[2].Text = Price.ToString("c");
        
         }         
 
      }
 
</script>
 
<body>
 
   <form runat=server>

      <h3>DataGrid ItemDataBound Example</h3>
 
      <asp:DataGrid id="ItemsGrid" runat="server"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="true">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>
   
      </asp:DataGrid>

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

プラットフォーム

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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0

参照

関連項目
DataGrid クラス
DataGrid メンバ
System.Web.UI.WebControls 名前空間
ItemDataBound
DataGridItemEventArgs
DataGridItemEventHandler

>> 「DataGrid.OnItemDataBound メソッド」を含む用語の索引
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DataGrid.OnItemDataBound メソッドとは？ わかりやすく解説

DataGrid.OnItemDataBound メソッド

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DataGrid.OnItemDataBound メソッドとは？わかりやすく解説