microsoft-visualbasic-runtime/ApplicationServices/Terminal/Utility/UserTaskCancelAction.vb

#Region "Microsoft.VisualBasic::1185cde58c7a8dc179cafbb41aac9979, Microsoft.VisualBasic.Core\ApplicationServices\Terminal\Utility\UserTaskCancelAction.vb"

    ' Author:
    ' 
    '       asuka (amethyst.asuka@gcmodeller.org)
    '       xie (genetics@smrucc.org)
    '       xieguigang (xie.guigang@live.com)
    ' 
    ' Copyright (c) 2018 GPL3 Licensed
    ' 
    ' 
    ' GNU GENERAL PUBLIC LICENSE (GPL3)
    ' 
    ' 
    ' This program is free software: you can redistribute it and/or modify
    ' it under the terms of the GNU General Public License as published by
    ' the Free Software Foundation, either version 3 of the License, or
    ' (at your option) any later version.
    ' 
    ' This program is distributed in the hope that it will be useful,
    ' but WITHOUT ANY WARRANTY; without even the implied warranty of
    ' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    ' GNU General Public License for more details.
    ' 
    ' You should have received a copy of the GNU General Public License
    ' along with this program. If not, see <http://www.gnu.org/licenses/>.



    ' /********************************************************************************/

    ' Summaries:

    '     Class UserTaskCancelAction
    ' 
    '         Constructor: (+1 Overloads) Sub New
    ' 
    '         Function: ToString
    ' 
    '         Sub: (+2 Overloads) Dispose, handleCancel
    ' 
    ' 
    ' /********************************************************************************/

#End Region

Namespace ApplicationServices.Terminal.Utility

    ''' <summary>
    ''' A finalize action after the user cancel current task operations.
    ''' </summary>
    Public Class UserTaskCancelAction : Implements IDisposable

        ReadOnly finalizeAction As Action

        Sub New(finalize As Action)
            finalizeAction = finalize

            AddHandler Console.CancelKeyPress, AddressOf handleCancel
        End Sub

        Private Sub handleCancel(sender As Object, terminate As ConsoleCancelEventArgs)
            ' ctrl + C just break the current executation
            ' not exit program running
            terminate.Cancel = True
            finalizeAction()
        End Sub

        Public Overrides Function ToString() As String
            Return finalizeAction.ToString
        End Function

#Region "IDisposable Support"
        Private disposedValue As Boolean ' 要检测冗余调用

        ' IDisposable
        Protected Overridable Sub Dispose(disposing As Boolean)
            If Not disposedValue Then
                If disposing Then
                    ' TODO: 释放托管状态(托管对象)。
                    RemoveHandler Console.CancelKeyPress, AddressOf handleCancel
                End If

                ' TODO: 释放未托管资源(未托管对象)并在以下内容中替代 Finalize()。
                ' TODO: 将大型字段设置为 null。
            End If
            disposedValue = True
        End Sub

        ' TODO: 仅当以上 Dispose(disposing As Boolean)拥有用于释放未托管资源的代码时才替代 Finalize()。
        'Protected Overrides Sub Finalize()
        '    ' 请勿更改此代码。将清理代码放入以上 Dispose(disposing As Boolean)中。
        '    Dispose(False)
        '    MyBase.Finalize()
        'End Sub

        ' Visual Basic 添加此代码以正确实现可释放模式。
        Public Sub Dispose() Implements IDisposable.Dispose
            ' 请勿更改此代码。将清理代码放入以上 Dispose(disposing As Boolean)中。
            Dispose(True)
            ' TODO: 如果在以上内容中替代了 Finalize()，则取消注释以下行。
            ' GC.SuppressFinalize(Me)
        End Sub
#End Region
    End Class
End Namespace