VB.NET一个秘密的类:简单但强大
发布时间:2020-12-16 22:47:42 所属栏目:大数据 来源:网络整理
导读:Namespace My '右击解决方案的属性时,在“Application(应用)”中,单击“View Application Events”便自动产生一个新的ApplicationEvents.vb。在此 '里面共有五个事件。 '这是特别的类,几乎被很多开发者忽略,但是功能最简单,却是却实用的类, ' The foll
Namespace My '右击解决方案的属性时,在“Application(应用)”中,单击“View Application Events”便自动产生一个新的ApplicationEvents.vb。在此 '里面共有五个事件。 '这是特别的类,几乎被很多开发者忽略,但是功能最简单,却是却实用的类, ' The following events are available for MyApplication: ' ' Startup: Raised when the application starts,before the startup form is created. ' Shutdown: Raised after all application forms are closed. This event is not raised if the application terminates abnormally. ' UnhandledException: Raised if the application encounters an unhandled exception. ' StartupNextInstance: Raised when launching a single-instance application and the application is already active. ' NetworkAvailabilityChanged: Raised when the network connection is connected or disconnected. Partial Friend Class MyApplication '检测计算是否接入网络 Private Sub MyApplication_NetworkAvailabilityChanged(sender As Object,e As Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs) Handles Me.NetworkAvailabilityChanged SetConnectionStatus(e.IsNetworkAvailable) End Sub '当应用程序各个窗体都关闭了。这个程序才运行,也是最后运行的程序 Private Sub MyApplication_Shutdown(sender As Object,e As System.EventArgs) Handles Me.Shutdown MsgBox("程序已经关闭运行!") End Sub '当应用程序最开始启动时就运行了。早于任何窗体,在这个地方来初始化变量是最好的 Private Sub MyApp_Startup(ByVal sender As Object,ByVal e As Microsoft.VisualBasic.ApplicationServices.StartupEventArgs) Handles Me.Startup ' When the application starts,set the connection status on the status strip MsgBox("程序将要开始启动") End Sub Public Sub SetConnectionStatus(ByVal connected As Boolean) 'With My.Forms.MainForm.ConnectedStatusLabel ' If (connected) Then ' .Image = My.Resources.connected.ToBitmap ' .Text = My.Resources.ConnectedText ' Else ' .Image = My.Resources.disconnected.ToBitmap ' .Text = My.Resources.DisconnectedText ' End If 'End With End Sub Private Sub MyApplication_StartupNextInstance(sender As Object,e As Microsoft.VisualBasic.ApplicationServices.StartupNextInstanceEventArgs) Handles Me.StartupNextInstance MsgBox("程序已经启动一次了") End Sub '当程序在运行中出错,而未作处理时,它是来收集错误并提示错误内容 Private Sub MyApplication_UnhandledException(sender As Object,e As Microsoft.VisualBasic.ApplicationServices.UnhandledExceptionEventArgs) Handles Me.UnhandledException MsgBox("程序在运行中出现错误") End Sub End Class End Namespace (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |