ObjectDataSource.Deleted イベントとは何？わかりやすく解説 Weblio辞書

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.NET Framework クラスライブラリリファレンス

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ObjectDataSource.Deleted イベント

メモ : このイベントは、.NET Framework version 2.0 で新しく追加されたものです。

Delete 操作の完了時に発生します。

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 Event Deleted As
 ObjectDataSourceStatusEventHandler

Visual Basic (使用法)

Dim instance As ObjectDataSource
Dim handler As ObjectDataSourceStatusEventHandler

AddHandler instance.Deleted, handler

public event ObjectDataSourceStatusEventHandler Deleted

C++

public:
event ObjectDataSourceStatusEventHandler^ Deleted {
    void add (ObjectDataSourceStatusEventHandler^ value);
    void remove (ObjectDataSourceStatusEventHandler^ value);
}

/** @event */
public void add_Deleted (ObjectDataSourceStatusEventHandler
 value)

/** @event */
public void remove_Deleted (ObjectDataSourceStatusEventHandler
 value)

JScript

JScript では、イベントは使用できますが、新規に宣言することはできません。

解説

Deleted イベントを処理することで、戻り値や出力パラメータの値を調べたり、Delete 操作の完了後に例外がスローされたかどうかを確認したりします。戻り値、出力パラメータ、および例外処理プロパティは、イベントに関連付けられた ObjectDataSourceStatusEventArgs オブジェクトから利用できます。

ObjectDataSourceStatusEventArgs オブジェクトの AffectedRows プロパティを使用すると、削除された行数を Delete メソッドから返すことができます。これを行うには、AffectedRows プロパティを設定します。削除された行数を DeleteMethod プロパティで指定されたメソッドから返す場合、返された値は ObjectDataSourceStatusEventArgs オブジェクトの ReturnValue プロパティから利用できます。

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

このセクションには、2 つのコード例が含まれています。1 つ目のコード例では、ビジネスオブジェクトおよび GridView コントロールで、ObjectDataSource オブジェクトを使用してデータを削除する方法を示します。2 つ目のコード例では、1 つ目のコード例で使用されている EmployeeLogic クラスを示します。

ビジネスオブジェクトおよび GridView コントロールで、ObjectDataSource コントロールを使用してデータを削除する方法を次のコード例に示します。GridView コントロールは、SelectMethod プロパティで指定されたメソッドを使用して EmployeeLogic オブジェクトからデータを取得し、最初に全従業員を表示します。AutoGenerateDeleteButton プロパティが true に設定されているため、GridView コントロールは自動的に削除ボタンを表示します。

[削除] ボタンをクリックすると、DeleteMethod プロパティで指定されたメソッド、および DeleteParameters コレクションで指定されたパラメータを使用して、削除操作が実行されます。このコード例では、プリプロセスとポストプロセスのステップも一部実行されます。操作の実行前に Deleting イベントを処理する場合は、NorthwindEmployeeDeleting デリゲートが呼び出されます。また、例外処理を実行するために、操作の完了後に Deleted イベントを処理する場合は、NorthwindEmployeeDeleted デリゲートが呼び出されます。このコード例では、NorthwindDataException がスローされた場合、NorthwindEmployeeDeleted メソッドによって処理されます。

Visual Basic

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB"
 Assembly="Samples.AspNet.VB"
 %>
<%@ Import namespace="Samples.AspNet.VB"
 %>
<%@ Page language="vb" %>
<Script runat="server">
' Called before a Delete operation.
    Private Sub NorthwindEmployeeDeleting(ByVal
 source As Object, ByVal
 e As ObjectDataSourceMethodEventArgs)

        ' The GridView passes the ID of the employee
        ' to be deleted. However, the business object, EmployeeLogic
,
        ' requires a NorthwindEmployee parameter, named "ne".
 Create
        ' it now and add it to the parameters collection.
        Dim paramsFromPage As IDictionary =
 e.InputParameters
  
        If Not paramsFromPage("EmpID")
 Is Nothing Then
    
            Dim ne As New
 NorthwindEmployee(paramsFromPage("EmpID").ToString())
            ' Remove the old EmpID parameter.
            paramsFromPage.Clear()
            paramsFromPage.Add("ne", ne)
    
    
        End If
    End Sub ' NorthwindEmployeeDeleting

    ' Called after a Delete operation.
    Private Sub NorthwindEmployeeDeleted(ByVal
 source As Object, ByVal
 e As ObjectDataSourceStatusEventArgs)
        ' Handle the Exception if it is a NorthwindDataException.
        If Not e.Exception Is
 Nothing Then

            ' Handle the specific exception type. The ObjectDataSource
 wraps
            ' any Exceptions in a TargetInvokationException wrapper,
 so
            ' check the InnerException property for the expected Exception
 types.
            If e.Exception.InnerException.GetType().Equals(GetType(NorthwindDataException))
 Then

                Label1.Text = e.Exception.InnerException.Message
                ' Because the exception is handled, there is
                ' no reason to throw it.
                e.ExceptionHandled = True
      
            End If
        End If
    End Sub ' NorthwindEmployeeDeleted
</Script>
<html>
  <head>
    <title>ObjectDataSource - VB Example</title>
  </head>
  <body>
    <form id="Form1" method="post"
 runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          autogeneratecolumns="false"
          datakeynames="EmpID">
          <columns>
            <asp:boundfield headertext="EmpID"
 datafield="EmpID" />
            <asp:boundfield headertext="First Name"
 datafield="FirstName" />
            <asp:boundfield headertext="Last Name"
 datafield="LastName" />
          </columns>
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          ondeleting="NorthwindEmployeeDeleting"
          ondeleted="NorthwindEmployeeDeleted"
          typename="Samples.AspNet.VB.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="EmpID" type="Int32"
 />
          </deleteparameters>
        </asp:objectdatasource>

        <asp:label id="Label1" runat="server"
 />

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

<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS"
 Assembly="Samples.AspNet.CS" %>
<%@ Import namespace="Samples.AspNet.CS" %>
<%@ Page language="c#" %>
<Script runat="server">
private void NorthwindEmployeeDeleting(object
 source, ObjectDataSourceMethodEventArgs e)
{
  // The GridView passes the ID of the employee
  // to be deleted. However, the buisiness object, EmployeeLogic,
  // requires a NorthwindEmployee parameter, named "ne". Create
  // it now and add it to the parameters collection.
  IDictionary paramsFromPage = e.InputParameters;
  if (paramsFromPage["EmpID"] != null)
 {
    NorthwindEmployee ne
      = new NorthwindEmployee( Int32.Parse(paramsFromPage["EmpID"].ToString()));
    // Remove the old EmpID parameter.
    paramsFromPage.Clear();
    paramsFromPage.Add("ne", ne);
  }
}

private void NorthwindEmployeeDeleted(object
 source, ObjectDataSourceStatusEventArgs e)
{
  // Handle the Exception if it is a NorthwindDataException
  if (e.Exception != null)
  {

    // Handle the specific exception type. The ObjectDataSource wraps
    // any Exceptions in a TargetInvokationException wrapper, so
    // check the InnerException property for expected Exception types.
    if (e.Exception.InnerException is NorthwindDataException)
    {
      Label1.Text = e.Exception.InnerException.Message;
      // Because the exception is handled, there is
      // no reason to throw it.
      e.ExceptionHandled = true;
    }
  }
}

</Script>
<html>
  <head>
    <title>ObjectDataSource - C# Example</title>
  </head>
  <body>
    <form id="Form1" method="post" runat="server">

        <asp:gridview
          id="GridView1"
          runat="server"
          datasourceid="ObjectDataSource1"
          autogeneratedeletebutton="true"
          autogeneratecolumns="false"
          datakeynames="EmpID">
          <columns>
            <asp:boundfield headertext="EmpID" datafield="EmpID"
 />
            <asp:boundfield headertext="First Name" datafield="FirstName"
 />
            <asp:boundfield headertext="Last Name" datafield="LastName"
 />
          </columns>
        </asp:gridview>

        <asp:objectdatasource
          id="ObjectDataSource1"
          runat="server"
          selectmethod="GetAllEmployees"
          deletemethod="DeleteEmployee"
          ondeleting="NorthwindEmployeeDeleting"
          ondeleted="NorthwindEmployeeDeleted"
          typename="Samples.AspNet.CS.EmployeeLogic">
          <deleteparameters>
            <asp:parameter name="EmpID" type="Int32" />
          </deleteparameters>
        </asp:objectdatasource>

        <asp:label id="Label1" runat="server" />

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

前のコード例で使用されている EmployeeLogic クラスを次のコード例に示します。

Visual Basic

Imports System
Imports System.Collections
Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace Samples.AspNet.VB
'
' EmployeeLogic is a stateless business object that encapsulates
' the operations you can perform on a NorthwindEmployee object.
Public Class EmployeeLogic

   ' Return a collection of NorthwindEmployee objects.
   Public Shared Function
 GetAllEmployees() As ICollection
      Dim al As New ArrayList()

      ' Use the SqlDataSource class to wrap the
      ' ADO.NET code required to query the database.
      Dim cts As ConnectionStringSettings =
 ConfigurationManager.ConnectionStrings("NorthwindConnection")
      Dim sds As New SqlDataSource(cts.ConnectionString,
 _
                                  "SELECT EmployeeID FROM Employees")
      Try
         Dim IDs As IEnumerable = sds.Select(DataSourceSelectArguments.Empty)

         ' Iterate through the Enumeration and create a
         ' NorthwindEmployee object for each ID.
         Dim enumerator As IEnumerator = IDs.GetEnumerator()
         While enumerator.MoveNext()
            ' The IEnumerable contains DataRowView objects.
            Dim row As DataRowView = CType(enumerator.Current
,DataRowView)
            Dim id As String
 = row("EmployeeID").ToString()
            Dim nwe As New
 NorthwindEmployee(id)
            ' Add the NorthwindEmployee object to the collection.
            al.Add(nwe)
         End While
      Finally
         ' If anything strange happens, clean up.
         sds.Dispose()
      End Try

      Return al
   End Function 'GetAllEmployees


   Public Shared Function
 GetEmployee(anID As Object) As
 NorthwindEmployee
      Return New NorthwindEmployee(anID)
   End Function 'GetEmployee


   Public Shared Sub DeleteEmployee(ne
 As NorthwindEmployee)
      Dim retval As Boolean
 = ne.Delete()
      If Not retval Then
         Throw New NorthwindDataException("Employee
 delete failed.")
      End If ' Delete the object
 in memory.
      ne = Nothing
   End Sub 'DeleteEmployee


   Public Shared Sub DeleteEmployeeByID(anID
 As Integer)
      Dim tempEmp As New
 NorthwindEmployee(anID)
      DeleteEmployee(tempEmp)
   End Sub 'DeleteEmployeeByID

End Class 'EmployeeLogic

Public Class NorthwindEmployee

   Public Sub New()
      ID = DBNull.Value
      aLastName = ""
      aFirstName = ""
   End Sub 'New


   Public Sub New(anID As
 Object)
      Me.ID = anID
      Dim cts As ConnectionStringSettings =
 ConfigurationManager.ConnectionStrings("NorthwindConnection")
      Dim conn As New SqlConnection(cts.ConnectionString)
      Dim sc As New SqlCommand("
 SELECT FirstName,LastName " & _
                               " FROM Employees "
 & _
                               " WHERE EmployeeID = @empId",
 conn)
      ' Add the employee ID parameter and set its value.
      sc.Parameters.Add(New SqlParameter("@empId",
 SqlDbType.Int)).Value = Int32.Parse(anID.ToString())
      Dim sdr As SqlDataReader = Nothing

      Try
         conn.Open()
         sdr = sc.ExecuteReader()

         ' This is not a while loop. It only loops once.
         If Not (sdr Is
 Nothing) AndAlso sdr.Read() Then
            ' The IEnumerable contains DataRowView objects.
            Me.aFirstName = sdr("FirstName").ToString()
            Me.aLastName = sdr("LastName").ToString()
         Else
            Throw New NorthwindDataException("Data
 not loaded for employee id.")
         End If
      Finally
         Try
            If Not (sdr Is
 Nothing) Then
               sdr.Close()
            End If
            conn.Close()
         Catch se As SqlException
            ' Log an event in the Application Event Log.
            Throw
         End Try
      End Try
   End Sub 'New

   Private ID As Object
   Public ReadOnly Property
 EmpID() As Object
      Get
         Return ID
      End Get
   End Property

   Private aLastName As String
   Public Property LastName() As
 String
      Get
         Return aLastName
      End Get
      Set
         aLastName = value
      End Set
   End Property

   Private aFirstName As String
   Public Property FirstName() As
 String
      Get
         Return aFirstName
      End Get
      Set
         aFirstName = value
      End Set
   End Property

   Public Function Delete() As
 Boolean
      If ID.Equals(DBNull.Value) Then
         ' The Employee object is not persisted.
         Return True
      Else
         ' The Employee object is persisted.
         ' Use the SqlDataSource control as a convenient wrapper for
         ' the ADO.NET code needed to delete a record from the database.
         Dim cts As ConnectionStringSettings =
 ConfigurationManager.ConnectionStrings("NorthwindConnection")
         Dim sds As New
 SqlDataSource()
         Try
            sds.ConnectionString = cts.ConnectionString
            sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID"
            sds.DeleteParameters.Add(New Parameter("empID",
 TypeCode.Int32, Me.ID.ToString()))

            ' Implement the remainder of the Delete() method.
            '
            Throw New NorthwindDataException("Delete()
 method not completely implemented.")

            Return True
         Finally
            ' Clean up resources.
            sds.Dispose()
         End Try
      End If
   End Function 'Delete
End Class 'NorthwindEmployee

Public Class NorthwindDataException
   Inherits Exception

   Public Sub New(msg As
 String)
      MyBase.New(msg)
   End Sub 'New

End Class 'NorthwindDataException
End Namespace

namespace Samples.AspNet.CS {

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
  //
  // EmployeeLogic is a stateless business object that encapsulates
  // the operations you can perform on a NorthwindEmployee object.
  //
  public class EmployeeLogic {

    // Returns a collection of NorthwindEmployee objects.
    public static ICollection GetAllEmployees
 () {
      ArrayList al = new ArrayList();

      // Use the SqlDataSource class to wrap the
      // ADO.NET code required to query the database.
      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];

      SqlDataSource sds
        = new SqlDataSource(cts.ConnectionString,
                            "SELECT EmployeeID FROM Employees");
      try {
        IEnumerable IDs = sds.Select(DataSourceSelectArguments.Empty);

        // Iterate through the Enumeration and create a
        // NorthwindEmployee object for each ID.
        IEnumerator enumerator = IDs.GetEnumerator();
        while (enumerator.MoveNext()) {
          // The IEnumerable contains DataRowView objects.
          DataRowView row = enumerator.Current as DataRowView;
          string id = row["EmployeeID"].ToString();
          NorthwindEmployee nwe = new NorthwindEmployee(id);
          // Add the NorthwindEmployee object to the collection.
          al.Add(nwe);
        }
      }
      finally {
        // If anything strange happens, clean up.
        sds.Dispose();
      }

      return al;
    }

    public static NorthwindEmployee GetEmployee(object
 anID) {
      return new NorthwindEmployee(anID);
    }

    public static void DeleteEmployee(NorthwindEmployee
 ne) {
      bool retval = ne.Delete();
      if (! retval) { throw new NorthwindDataException("Employee
 delete failed."); }
      // Delete the object in memory.
      ne = null;
    }

    public static void DeleteEmployeeByID(int
 anID) {
        NorthwindEmployee tempEmp = new NorthwindEmployee(anID);
        DeleteEmployee(tempEmp);
    }
  }

  public class NorthwindEmployee {

    public NorthwindEmployee () {
      ID = DBNull.Value;
      lastName = "";
      firstName = "";
    }

    public NorthwindEmployee (object anID) {
      this.ID = anID;

      ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];

      SqlConnection conn = new SqlConnection (cts.ConnectionString);
      SqlCommand sc =
        new SqlCommand(" SELECT FirstName,LastName "
 +
                       " FROM Employees " +
                       " WHERE EmployeeID = @empId",
                       conn);
      // Add the employee ID parameter and set its value.
      sc.Parameters.Add(new SqlParameter("@empId",SqlDbType.Int)).Value
 = Int32.Parse(anID.ToString());
      SqlDataReader sdr = null;

      try {
        conn.Open();
        sdr = sc.ExecuteReader();

        // This is not a while loop. It only loops once.
        if (sdr != null && sdr.Read())
 {
          // The IEnumerable contains DataRowView objects.
          this.firstName        = sdr["FirstName"].ToString();
          this.lastName         = sdr["LastName"].ToString();
        }
        else {
          throw new NorthwindDataException("Data not loaded
 for employee id.");
        }
      }
      finally {
        try {
          if (sdr != null) sdr.Close();
          conn.Close();
        }
        catch (SqlException) {
          // Log an event in the Application Event Log.
          throw;
        }
      }
    }

    private object ID;
    public object EmpID {
      get { return ID; }
    }

    private string lastName;
    public string LastName {
      get { return lastName; }
      set { lastName = value; }
    }

    private string firstName;
    public string FirstName {
      get { return firstName; }
      set { firstName = value;  }
    }
    public bool Delete () {
      if (ID.Equals(DBNull.Value)) {
        // The Employee object is not persisted.
        return true;
      }
      else {
        // The Employee object is persisted.
        // Use the SqlDataSource control as a convenient wrapper for
        // the ADO.NET code needed to delete a record from the database.
        ConnectionStringSettings cts = ConfigurationManager.ConnectionStrings["NorthwindConnection"];
        SqlDataSource sds = new SqlDataSource();

        try {
          sds.ConnectionString = cts.ConnectionString;
          sds.DeleteCommand = "DELETE FROM Employees WHERE EmployeeID=@empID";
          sds.DeleteParameters.Add(new Parameter("empID"
,TypeCode.Int32,this.ID.ToString()));

          //
          // Implement the remainder of the Delete() method.
          //
          throw new NorthwindDataException("Delete() method
 not completely implemented.");
        }
        finally {
          // Clean up resources.
          sds.Dispose();
        }
      }
    }
  }

  public class NorthwindDataException: Exception
 {
    public NorthwindDataException(string msg)
 : base (msg) { }
  }
}

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

参照

関連項目
ObjectDataSource クラス
ObjectDataSource メンバ
System.Web.UI.WebControls 名前空間
Deleting
OnDeleted
Delete
ObjectDataSource.DeleteParameters プロパティ

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ObjectDataSource.Deleted イベントとは？ わかりやすく解説

ObjectDataSource.Deleted イベント

急上昇のことば

「ObjectDataSource.Deleted イベント」の関連用語

ObjectDataSource.Deleted イベントとは？わかりやすく解説