SqlCommand.Cancel 메서드

정의

네임스페이스:
System.Data.SqlClient
어셈블리:
System.Data.dll

의 실행을 취소하려고 시도합니다 SqlCommand.

public:
 virtual void Cancel();
public:
 override void Cancel();
public void Cancel();
public override void Cancel();
abstract member Cancel : unit -> unit
override this.Cancel : unit -> unit
override this.Cancel : unit -> unit
Public Sub Cancel ()
Public Overrides Sub Cancel ()

구현

Cancel()

예제

다음 예제에서는 Cancel 메서드를 사용하는 방법을 보여 줍니다.

using System;
using System.Data;
using System.Data.SqlClient;
using System.Threading;

class Program
{
    private static SqlCommand m_rCommand;

    public static SqlCommand Command
    {
        get { return m_rCommand; }
        set { m_rCommand = value; }
    }

    public static void Thread_Cancel()
    {
        Command.Cancel();
    }

    static void Main()
    {
        string connectionString = GetConnectionString();
        try
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();

                Command = connection.CreateCommand();
                Command.CommandText = "DROP TABLE TestCancel";
                try
                {
                    Command.ExecuteNonQuery();
                }
                catch { }

                Command.CommandText = "CREATE TABLE TestCancel(co1 int, co2 char(10))";
                Command.ExecuteNonQuery();
                Command.CommandText = "INSERT INTO TestCancel VALUES (1, '1')";
                Command.ExecuteNonQuery();

                Command.CommandText = "SELECT * FROM TestCancel";
                SqlDataReader reader = Command.ExecuteReader();

                Thread rThread2 = new Thread(new ThreadStart(Thread_Cancel));
                rThread2.Start();
                rThread2.Join();

                reader.Read();
                System.Console.WriteLine(reader.FieldCount);
                reader.Close();
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
    static private string GetConnectionString()
    {
        // To avoid storing the connection string in your code,
        // you can retrieve it from a configuration file.
        return "Data Source=(local);Initial Catalog=AdventureWorks;"
            + "Integrated Security=SSPI";
    }
}

Imports System.Data
Imports System.Data.SqlClient
Imports System.Threading

Module Module1
    Private m_rCommand As SqlCommand

    Public Property Command() As SqlCommand
        Get
            Return m_rCommand
        End Get
        Set(ByVal value As SqlCommand)
            m_rCommand = value
        End Set
    End Property

    Public Sub Thread_Cancel()
        Command.Cancel()
    End Sub

    Sub Main()
        Dim connectionString As String = GetConnectionString()

        Try
            Using connection As New SqlConnection(connectionString)

                connection.Open()

                Command = connection.CreateCommand()
                Command.CommandText = "DROP TABLE TestCancel"
                Try
                    Command.ExecuteNonQuery()
                Catch
                End Try

                Command.CommandText = "CREATE TABLE TestCancel(co1 int, co2 char(10))"
                Command.ExecuteNonQuery()
                Command.CommandText = "INSERT INTO TestCancel VALUES (1, '1')"
                Command.ExecuteNonQuery()

                Command.CommandText = "SELECT * FROM TestCancel"
                Dim reader As SqlDataReader = Command.ExecuteReader()

                Dim rThread2 As New Thread( _
                    New ThreadStart(AddressOf Thread_Cancel))

                rThread2.Start()
                rThread2.Join()

                reader.Read()
                Console.WriteLine(reader.FieldCount)
                reader.Close()
            End Using

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try
    End Sub

    Private Function GetConnectionString() As String
        ' To avoid storing the connection string in your code,  
        ' you can retrieve it from a configuration file.
        Return "Data Source=(local);Initial Catalog=AdventureWorks;" _
           & "Integrated Security=SSPI;"
    End Function
End Module

설명

취소할 항목이 없으면 아무 것도 발생하지 않습니다. 그러나 처리 중인 명령이 있고 취소 시도가 실패하는 경우 예외가 생성되지 않습니다.

드물게 ExecuteReader 호출한 다음 Cancel 호출하기 전에 Close(암시적 또는 명시적으로)를 호출한 다음 Cancel 호출하면 취소 명령이 SQL Server 전송되지 않으며 Close 호출한 후에도 결과 집합이 계속 스트리밍될 수 있습니다. 이 문제를 방지하려면 판독기 또는 연결을 닫기 전에 호출 Cancel 해야 합니다.

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