DataListCommandEventHandler デリゲートとは何？わかりやすく解説 Weblio辞書

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DataListCommandEventHandler デリゲート

DataList コントロールの CancelCommand、DeleteCommand、EditCommand、ItemCommand、UpdateCommand の各イベントを処理するメソッドを表します。

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)

Public Delegate Sub DataListCommandEventHandler
 ( _
    source As Object, _
    e As DataListCommandEventArgs _
)

Visual Basic (使用法)

Dim instance As New DataListCommandEventHandler(AddressOf
 HandlerMethod)

public delegate void DataListCommandEventHandler
 (
    Object source,
    DataListCommandEventArgs e
)

C++

public delegate void DataListCommandEventHandler
 (
    Object^ source, 
    DataListCommandEventArgs^ e
)

/** @delegate */
public delegate void DataListCommandEventHandler
 (
    Object source, 
    DataListCommandEventArgs e
)

JScript

JScript では、デリゲートは使用できますが、新規に宣言することはできません。

パラメータ

source: イベントのソース。

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

解説

CancelCommand イベントは、DataList コントロールの項目の Cancel ボタンがクリックされると発生します。

DeleteCommand イベントは、DataList コントロールの項目の Delete ボタンがクリックされると発生します。

EditCommand イベントは、DataList コントロールの項目の Edit ボタンがクリックされると発生します。

ItemCommand イベントは、DataList コントロール内の項目で、ボタンがクリックされたときに発生します。これにより、特定のコマンドボタンがクリックされたタイミングをプログラムによって判断し、適切なアクションを実行できます。このイベントは、通常 DataList コントロールのカスタムコマンドボタンを処理するために使用します。

UpdateCommand イベントは、DataList コントロールの項目の Update ボタンがクリックされると発生します。

DataListCommandEventHandler デリゲートを作成する場合は、イベントを処理するメソッドを識別してください。イベントをイベントハンドラに関連付けるには、デリゲートのインスタンスをイベントに追加します。デリゲートを削除しない限り、そのイベントが発生すると常にイベントハンドラが呼び出されます。イベントハンドラデリゲートの詳細については、「イベントとデリゲート」を参照してください。

使用例

DataList コントロールの EditCommand、UpdateCommand、CancelCommand、および DeleteCommand の各イベントのイベントハンドラを定義する方法を次の例に示します。この例では、DataList コントロールの各コマンドプロパティのイベントハンドラを設定し、宣言によってイベントハンドラを指定します。

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True"
 %>
<%@ Import Namespace="System.Data"
 %>

<html>
<head>

   <script runat="server">

      ' The Cart and CartView objects temporarily store the data source
      ' for the DataList control while the page is being processed.
      Dim Cart As DataTable = New
 DataTable()
      Dim CartView As DataView
 
      Sub Page_Load(sende As Object,
 e As EventArgs) 
 
         ' With a database, use an select query to retrieve the data.
         ' Because the data source in this example is an in-memory
         ' DataTable, retrieve the data from session state if it exists;
         ' otherwise, create the data source.
         GetSource()

         ' The DataGrid control maintains state between posts to the
 server;
         ' it only needs to be bound to a data source the first time
 the
         ' page is loaded or when the data source is updated.
         If Not IsPostBack Then

            BindList()

         End If
                   
      End Sub

      Sub BindList() 

         ' Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView
         ItemsList.DataBind()

      End Sub

      Sub GetSource()

         ' For this example, the data source is a DataTable that
         ' is stored in session state. If the data source does not exist
,
         ' create it; otherwise, load the data.
         If Session("ShoppingCart")
 Is Nothing Then 

            ' Create the sample data.
            Dim dr As DataRow  
 
            ' Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty",
 GetType(Int32)))
            Cart.Columns.Add(new DataColumn("Item",
 GetType(String)))
            Cart.Columns.Add(new DataColumn("Price",
 GetType(Double)))

            ' Store the table in session state to persist its values
            ' between posts to the server.
            Session("ShoppingCart") = Cart
             
            ' Populate the DataTable with sample data.
            Dim i As Integer

            For i = 1 To 9 
            
               dr = Cart.NewRow()
               If (i Mod 2) <> 0 Then

                  dr(0) = 2
               
               Else
               
                  dr(0) = 1
               
               End If

               dr(1) = "Item " & i.ToString()
               dr(2) = (1.23 * (i + 1))
               Cart.Rows.Add(dr)
            
            Next i

         Else

            ' Retrieve the sample data from session state.
            Cart = CType(Session("ShoppingCart"),
 DataTable)

         End If         
 
         ' Create a DataView and specify the field to sort by.
         CartView = New DataView(Cart)
         CartView.Sort="Item"

         Return

      End Sub

      Sub Edit_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to the index of the item clicked
         ' in the DataList control to enable editing for that item.
 Be sure
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = e.Item.ItemIndex
         BindList()

      End Sub

      Sub Cancel_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Delete_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Retrieve the name of the item to remove.
         Dim item As String
 = (CType(e.Item.FindControl("ItemLabel"), Label)).Text

         ' Filter the CartView for the selected item and remove it from
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' Set the EditItemIndex property to -1 to exit editing mode.
 Be sure 
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Update_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Retrieve the updated values from the selected item.
         Dim item As String
 = _
             (CType(e.Item.FindControl("ItemLabel"),
 Label)).Text
         Dim qty As String
 = _
             (CType(e.Item.FindControl("QtyTextBox"),
 TextBox)).Text
         Dim price As String
 = _
             (CType(e.Item.FindControl("PriceTextBox"),
 TextBox)).Text

         ' With a database, use an update command to update the data.
         ' Because the data source in this example is an in-memory 
         ' DataTable, delete the old row and replace it with a new one.

         ' Filter the CartView for the selected item and remove it from
 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' ***************************************************************
         ' Insert data validation code here. Make sure to validate the
         ' values entered by the user before converting to the appropriate
         ' data types and updating the data source.
         ' ***************************************************************

         ' Add a new entry to replace the previous item.
         Dim dr As DataRow = Cart.NewRow()
         dr(0) = qty
         dr(1) = item
         ' If necessary, remove the '$' character from the price before
 
         ' converting the price to a Double.
         If price.Chars(0) = "$"
 Then

            dr(2) = Convert.ToDouble(price.Substring(1))

         Else

            dr(2) = Convert.ToDouble(price)
         
         End If

         Cart.Rows.Add(dr)

         ' Set the EditItemIndex property to -1 to exit editing mode.
 
         ' Be sure to rebind the DataList to the data source to refresh
 
         ' the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of
 the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item")
 %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty")
 %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item")
 %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty")
 %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      // The Cart and CartView objects temporarily store the data source
      // for the DataList control while the page is being processed.
      DataTable Cart = new DataTable();
      DataView CartView;   
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // With a database, use an select query to retrieve the data.
 
         // Because the data source in this example is an in-memory
         // DataTable, retrieve the data from session state if it exists;
         // otherwise, create the data source.
         GetSource();

         // The DataList control maintains state between posts to the
 server;
         // it only needs to be bound to a data source the first time
 the
         // page is loaded or when the data source is updated.
         if (!IsPostBack)
         {

            BindList();

         }
                   
      }

      void BindList() 
      {

         // Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView;
         ItemsList.DataBind();

      }

      void GetSource()
      {

         // For this example, the data source is a DataTable that 
         // is stored in session state. If the data source does not
 exist,
         // create it; otherwise, load the data.
         if (Session["ShoppingCart"] == null)
 
         {     

            // Create the sample data.
            DataRow dr;  
 
            // Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
            Cart.Columns.Add(new DataColumn("Item",
 typeof(String)));
            Cart.Columns.Add(new DataColumn("Price",
 typeof(Double)));

            // Store the table in session state to persist its values
 
            // between posts to the server.
            Session["ShoppingCart"] = Cart;
             
            // Populate the DataTable with sample data.
            for (int i = 1; i <= 9; i++)
 
            {
               dr = Cart.NewRow();
               if (i % 2 != 0)
               {
                  dr[0] = 2;
               }
               else
               {
                  dr[0] = 1;
               }
               dr[1] = "Item " + i.ToString();
               dr[2] = (1.23 * (i + 1));
               Cart.Rows.Add(dr);
            }

         } 

         else
         {

            // Retrieve the sample data from session state.
            Cart = (DataTable)Session["ShoppingCart"];

         }         
 
         // Create a DataView and specify the field to sort by.
         CartView = new DataView(Cart);
         CartView.Sort="Item";

         return;

      }

      void Edit_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Set the EditItemIndex property to the index of the item
 clicked
         // in the DataList control to enable editing for that item.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = e.Item.ItemIndex;
         BindList();

      }

      void Cancel_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Delete_Command(Object sender, DataListCommandEventArgs
 e) 
      { 

         // Retrieve the name of the item to remove.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;

         // Filter the CartView for the selected item and remove it
 from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0) 
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Update_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Retrieve the updated values from the selected item.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
         String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
         String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;

         // With a database, use an update command to update the data.
         // Because the data source in this example is an in-memory
 
         // DataTable, delete the old row and replace it with a new
 one.

         // Filter the CartView for the selected item and remove it
 from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0)
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // ***************************************************************
         // Insert data validation code here. Make sure to validate
 the
         // values entered by the user before converting to the appropriate
         // data types and updating the data source.
         // ***************************************************************

         // Add a new entry to replace the previous item.
         DataRow dr = Cart.NewRow();
         dr[0] = qty;
         dr[1] = item;
         // If necessary, remove the '$' character from the price before
         // converting the price to a Double.
         if(price[0] == '$')
         {
            dr[2] = Convert.ToDouble(price.Substring(1));
         }
         else
         {
            dr[2] = Convert.ToDouble(price);
         }
         Cart.Rows.Add(dr);

         // Set the EditItemIndex property to -1 to exit editing mode.
 
         // Be sure to rebind the DataList to the data source to refresh
         // the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}")
 %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item")
 %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty")
 %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>

Page_Load メソッドで、イベントハンドラを指定し、それらをプログラムによって各イベントに追加する方法を次のコード例に示します。

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True"
 %>
<%@ Import Namespace="System.Data"
 %>

<html>
<head>

   <script runat="server">

      ' The Cart and CartView objects temporarily store the data source
      ' for the DataList control while the page is being processed.
      Dim Cart As DataTable = New
 DataTable()
      Dim CartView As DataView
 
      Sub Page_Load(sende As Object,
 e As EventArgs) 
 
         ' With a database, use an select query to retrieve the data.
         ' Because the data source in this example is an in-memory
         ' DataTable, retrieve the data from session state if it exists;
         ' otherwise, create the data source.
         GetSource()

         ' The DataGrid control maintains state between posts to the
 server;
         ' it only needs to be bound to a data source the first time
 the
         ' page is loaded or when the data source is updated.
         If Not IsPostBack Then

            BindList()

         End If

         ' Manually register the event-handling methods.
         AddHandler ItemsList.EditCommand, AddressOf
 Edit_Command
         AddHandler ItemsList.UpdateCommand, AddressOf
 Update_Command
         AddHandler ItemsList.DeleteCommand, AddressOf
 Delete_Command
         AddHandler ItemsList.CancelCommand, AddressOf
 Cancel_Command
                   
      End Sub

      Sub BindList() 

         ' Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView
         ItemsList.DataBind()

      End Sub

      Sub GetSource()

         ' For this example, the data source is a DataTable that
         ' is stored in session state. If the data source does not exist
,
         ' create it; otherwise, load the data.
         If Session("ShoppingCart")
 Is Nothing Then 

            ' Create the sample data.
            Dim dr As DataRow  
 
            ' Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty",
 GetType(Int32)))
            Cart.Columns.Add(new DataColumn("Item",
 GetType(String)))
            Cart.Columns.Add(new DataColumn("Price",
 GetType(Double)))

            ' Store the table in session state to persist its values
            ' between posts to the server.
            Session("ShoppingCart") = Cart
             
            ' Populate the DataTable with sample data.
            Dim i As Integer

            For i = 1 To 9 
            
               dr = Cart.NewRow()
               If (i Mod 2) <> 0 Then

                  dr(0) = 2
               
               Else
               
                  dr(0) = 1
               
               End If

               dr(1) = "Item " & i.ToString()
               dr(2) = (1.23 * (i + 1))
               Cart.Rows.Add(dr)
            
            Next i

         Else

            ' Retrieve the sample data from session state.
            Cart = CType(Session("ShoppingCart"),
 DataTable)

         End If         
 
         ' Create a DataView and specify the field to sort by.
         CartView = New DataView(Cart)
         CartView.Sort="Item"

         Return

      End Sub

      Sub Edit_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to the index of the item clicked
         ' in the DataList control to enable editing for that item.
 Be sure
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = e.Item.ItemIndex
         BindList()

      End Sub

      Sub Cancel_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Delete_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Retrieve the name of the item to remove.
         Dim item As String
 = (CType(e.Item.FindControl("ItemLabel"), Label)).Text

         ' Filter the CartView for the selected item and remove it from
 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' Set the EditItemIndex property to -1 to exit editing mode.
 Be sure 
         ' to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

      Sub Update_Command(sender As Object,
 e As DataListCommandEventArgs) 

         ' Retrieve the updated values from the selected item.
         Dim item As String
 = _
             (CType(e.Item.FindControl("ItemLabel"),
 Label)).Text
         Dim qty As String
 = _
             (CType(e.Item.FindControl("QtyTextBox"),
 TextBox)).Text
         Dim price As String
 = _
             (CType(e.Item.FindControl("PriceTextBox"),
 TextBox)).Text

         ' With a database, use an update command to update the data.
         ' Because the data source in this example is an in-memory 
         ' DataTable, delete the old row and replace it with a new one.

         ' Filter the CartView for the selected item and remove it from
 
         ' the data source.
         CartView.RowFilter = "Item='" & item & "'"
         If CartView.Count > 0 Then 
       
            CartView.Delete(0)
         
         End If
         CartView.RowFilter = ""

         ' ***************************************************************
         ' Insert data validation code here. Make sure to validate the
         ' values entered by the user before converting to the appropriate
         ' data types and updating the data source.
         ' ***************************************************************

         ' Add a new entry to replace the previous item.
         Dim dr As DataRow = Cart.NewRow()
         dr(0) = qty
         dr(1) = item
         ' If necessary, remove the '$' character from the price before
 
         ' converting the price to a Double.
         If price.Chars(0) = "$"
 Then

            dr(2) = Convert.ToDouble(price.Substring(1))

         Else

            dr(2) = Convert.ToDouble(price)
         
         End If

         Cart.Rows.Add(dr)

         ' Set the EditItemIndex property to -1 to exit editing mode.
 
         ' Be sure to rebind the DataList to the data source to refresh
 
         ' the control.
         ItemsList.EditItemIndex = -1
         BindList()

      End Sub

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of
 the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           OnEditCommand="Edit_Command"
           OnUpdateCommand="Update_Command"
           OnDeleteCommand="Delete_Command"
           OnCancelCommand="Cancel_Command"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item")
 %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty")
 %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item")
 %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty")
 %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </form>

</body>
</html>

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

<html>
<head>

   <script runat="server">

      // The Cart and CartView objects temporarily store the data source
      // for the DataList control while the page is being processed.
      DataTable Cart = new DataTable();
      DataView CartView;   
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // With a database, use an select query to retrieve the data.
 
         // Because the data source in this example is an in-memory
         // DataTable, retrieve the data from session state if it exists;
         // otherwise, create the data source.
         GetSource();

         // The DataList control maintains state between posts to the
 server;
         // it only needs to be bound to a data source the first time
 the
         // page is loaded or when the data source is updated.
         if (!IsPostBack)
         {

            BindList();

         }

         // Manually register the event-handling methods.
         ItemsList.EditCommand += 
             new DataListCommandEventHandler(this.Edit_Command);
         ItemsList.UpdateCommand += 
             new DataListCommandEventHandler(this.Update_Command);
         ItemsList.DeleteCommand += 
             new DataListCommandEventHandler(this.Delete_Command);
         ItemsList.CancelCommand += 
             new DataListCommandEventHandler(this.Cancel_Command);
                   
      }

      void BindList() 
      {

         // Set the data source and bind to the DataList control.
         ItemsList.DataSource = CartView;
         ItemsList.DataBind();

      }

      void GetSource()
      {

         // For this example, the data source is a DataTable that 
         // is stored in session state. If the data source does not
 exist,
         // create it; otherwise, load the data.
         if (Session["ShoppingCart"] == null)
 
         {     

            // Create the sample data.
            DataRow dr;  
 
            // Define the columns of the table.
            Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
            Cart.Columns.Add(new DataColumn("Item",
 typeof(String)));
            Cart.Columns.Add(new DataColumn("Price",
 typeof(Double)));

            // Store the table in session state to persist its values
            // between posts to the server.
            Session["ShoppingCart"] = Cart;
             
            // Populate the DataTable with sample data.
            for (int i = 1; i <= 9; i++)
 
            {
               dr = Cart.NewRow();
               if (i % 2 != 0)
               {
                  dr[0] = 2;
               }
               else
               {
                  dr[0] = 1;
               }
               dr[1] = "Item " + i.ToString();
               dr[2] = (1.23 * (i + 1));
               Cart.Rows.Add(dr);
            }

         } 

         else
         {

            // Retrieve the sample data from session state.
            Cart = (DataTable)Session["ShoppingCart"];

         }         
 
         // Create a DataView and specify the field to sort by.
         CartView = new DataView(Cart);
         CartView.Sort="Item";

         return;

      }

      void Edit_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Set the EditItemIndex property to the index of the item
 clicked
         // in the DataList control to enable editing for that item.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = e.Item.ItemIndex;
         BindList();

      }

      void Cancel_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Delete_Command(Object sender, DataListCommandEventArgs
 e) 
      { 

         // Retrieve the name of the item to remove.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;

         // Filter the CartView for the selected item and remove it
 from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0) 
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // Set the EditItemIndex property to -1 to exit editing mode.
 Be sure
         // to rebind the DataList to the data source to refresh the
 control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

      void Update_Command(Object sender, DataListCommandEventArgs
 e) 
      {

         // Retrieve the updated values from the selected item.
         String item = ((Label)e.Item.FindControl("ItemLabel")).Text;
         String qty = ((TextBox)e.Item.FindControl("QtyTextBox")).Text;
         String price = ((TextBox)e.Item.FindControl("PriceTextBox")).Text;

         // With a database, use an update command to update the data.
         // Because the data source in this example is an in-memory
 
         // DataTable, delete the old row and replace it with a new
 one.

         // Filter the CartView for the selected item and remove it
 from
         // the data source.
         CartView.RowFilter = "Item='" + item + "'";
         if (CartView.Count > 0)
         {
            CartView.Delete(0);
         }
         CartView.RowFilter = "";

         // ***************************************************************
         // Insert data validation code here. Make sure to validate
 the
         // values entered by the user before converting to the appropriate
         // data types and updating the data source.
         // ***************************************************************

         // Add a new entry to replace the previous item.
         DataRow dr = Cart.NewRow();
         dr[0] = qty;
         dr[1] = item;
         // If necessary, remove the '$' character from the price before
         // converting the price to a Double.
         if(price[0] == '$')
         {
            dr[2] = Convert.ToDouble(price.Substring(1));
         }
         else
         {
            dr[2] = Convert.ToDouble(price);
         }
         Cart.Rows.Add(dr);

         // Set the EditItemIndex property to -1 to exit editing mode.
 
         // Be sure to rebind the DataList to the data source to refresh
         // the control.
         ItemsList.EditItemIndex = -1;
         BindList();

      }

   </script>

</head>
<body>

   <form runat=server>

      <h3>DataList Edit Example</h3>

      Click <b>Edit</b> to edit the values of the item.

      <br><br>
       
      <asp:DataList id="ItemsList"
           GridLines="Both"
           RepeatColumns="3"
           RepeatDirection="Horizontal"
           CellPadding="3"
           CellSpacing="0"
           runat="server">

         <HeaderStyle BackColor="#aaaadd">
         </HeaderStyle>

         <AlternatingItemStyle BackColor="Gainsboro">
         </AlternatingItemStyle>

         <EditItemStyle BackColor="yellow">
         </EditItemStyle>

         <HeaderTemplate>

            Items

         </HeaderTemplate>
         
         <ItemTemplate>

            Item:
            <%# DataBinder.Eval(Container.DataItem, "Item") %> 

            <br>

            Quantity:
            <%# DataBinder.Eval(Container.DataItem, "Qty") %>

            <br>

            Price:
            <%# DataBinder.Eval(Container.DataItem, "Price", "{0:c}")
 %>

            <br>

            <asp:LinkButton id="EditButton" 
                 Text="Edit" 
                 CommandName="Edit"
                 runat="server"/>

         </ItemTemplate>
              
         <EditItemTemplate>

            Item:
            <asp:Label id="ItemLabel" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Item")
 %>' 
                 runat="server"/>

            <br>

            Quantity:
            <asp:TextBox id="QtyTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Qty")
 %>' 
                 runat="server"/>

            <br>

            Price:
            <asp:TextBox id="PriceTextBox" 
                 Text='<%# DataBinder.Eval(Container.DataItem, "Price",
 "{0:c}") %>' 
                 runat="server"/>

            <br>

            <asp:LinkButton id="UpdateButton" 
                 Text="Update" 
                 CommandName="Update" 
                 runat="server"/>

            <asp:LinkButton id="DeleteButton" 
                 Text="Delete" 
                 CommandName="Delete" 
                 runat="server"/>

            <asp:LinkButton id="CancelButton" 
                 Text="Cancel" 
                 CommandName="Cancel" 
                 runat="server"/>

         </EditItemTemplate>

      </asp:DataList>

   </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
System.Web.UI.WebControls 名前空間
DataListCommandEventArgs クラス
DataList クラス
DataList.CancelCommand イベント
DataList.DeleteCommand イベント
DataList.EditCommand イベント
DataList.ItemCommand イベント
DataList.UpdateCommand イベント
その他の技術情報
DataList Web サーバーコントロール

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