CancelEventArgs Class
Provides data for a cancelable event.
Assembly: System (in System.dll)
The CancelEventArgs type exposes the following members.
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | CancelEventArgs() | Initializes a new instance of the CancelEventArgs class with the Cancel property set to false. |
![]() ![]() ![]() | CancelEventArgs(Boolean) | Initializes a new instance of the CancelEventArgs class with the Cancel property set to the given value. |
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() ![]() ![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() ![]() ![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() ![]() ![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() ![]() ![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() ![]() ![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
A cancelable event is raised by a component when it is about to perform an action that can be canceled, such as the Closing event of a Form.
Note |
|---|
The Closing event is deprecated and has been replaced by FormClosing. It is offered as an example here only to illustrate the usage of CancelEventArgs. |
CancelEventArgs provides the Cancel property to indicate whether the event should be canceled.
Note |
|---|
The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
The following example uses CancelEventArgs and a CancelEventHandler to handle the Closing event of a Form. This code assumes that you have created a Form with a class-level Boolean variable named isDataSaved. It also assumes that you have added a statement to invoke the OtherInitialize method from the form's Load method or the constructor (after the call to InitializeComponent).
private: // Call this method from the InitializeComponent() method of your form void OtherInitialize() { this->Closing += gcnew CancelEventHandler( this, &Form1::Form1_Cancel ); this->myDataIsSaved = true; } void Form1_Cancel( Object^ /*sender*/, CancelEventArgs^ e ) { if ( !myDataIsSaved ) { e->Cancel = true; MessageBox::Show( "You must save first." ); } else { e->Cancel = false; MessageBox::Show( "Goodbye." ); } }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
System::EventArgs
System.ComponentModel::CancelEventArgs
Microsoft.VisualBasic.ApplicationServices::StartupEventArgs
System.ComponentModel::DoWorkEventArgs
System.Configuration::SettingChangingEventArgs
System.Drawing.Printing::PrintEventArgs
System.Web.UI.WebControls::DetailsViewDeleteEventArgs
System.Web.UI.WebControls::DetailsViewInsertEventArgs
System.Web.UI.WebControls::DetailsViewModeEventArgs
System.Web.UI.WebControls::DetailsViewPageEventArgs
System.Web.UI.WebControls::DetailsViewUpdateEventArgs
System.Web.UI.WebControls::EntityDataSourceChangingEventArgs
System.Web.UI.WebControls::EntityDataSourceContextDisposingEventArgs
System.Web.UI.WebControls::EntityDataSourceSelectingEventArgs
System.Web.UI.WebControls::FormViewDeleteEventArgs
System.Web.UI.WebControls::FormViewInsertEventArgs
System.Web.UI.WebControls::FormViewModeEventArgs
System.Web.UI.WebControls::FormViewPageEventArgs
System.Web.UI.WebControls::FormViewUpdateEventArgs
System.Web.UI.WebControls::GridViewCancelEditEventArgs
System.Web.UI.WebControls::GridViewDeleteEventArgs
System.Web.UI.WebControls::GridViewEditEventArgs
System.Web.UI.WebControls::GridViewPageEventArgs
System.Web.UI.WebControls::GridViewSelectEventArgs
System.Web.UI.WebControls::GridViewSortEventArgs
System.Web.UI.WebControls::GridViewUpdateEventArgs
System.Web.UI.WebControls::LinqDataSourceDeleteEventArgs
System.Web.UI.WebControls::LinqDataSourceDisposeEventArgs
System.Web.UI.WebControls::LinqDataSourceInsertEventArgs
System.Web.UI.WebControls::LinqDataSourceSelectEventArgs
System.Web.UI.WebControls::LinqDataSourceUpdateEventArgs
System.Web.UI.WebControls::ListViewCancelEventArgs
System.Web.UI.WebControls::ListViewDeleteEventArgs
System.Web.UI.WebControls::ListViewEditEventArgs
System.Web.UI.WebControls::ListViewInsertEventArgs
System.Web.UI.WebControls::ListViewSelectEventArgs
System.Web.UI.WebControls::ListViewSortEventArgs
System.Web.UI.WebControls::ListViewUpdateEventArgs
System.Web.UI.WebControls::ObjectDataSourceDisposingEventArgs
System.Web.UI.WebControls::ObjectDataSourceFilteringEventArgs
System.Web.UI.WebControls::ObjectDataSourceMethodEventArgs
System.Web.UI.WebControls::SqlDataSourceCommandEventArgs
System.Web.UI.WebControls::SqlDataSourceFilteringEventArgs
System.Web.UI.WebControls.WebParts::WebPartCancelEventArgs
System.Web.UI.WebControls.WebParts::WebPartConnectionsCancelEventArgs
System.Web.UI.WebControls.WebParts::WebPartDisplayModeCancelEventArgs
System.Windows.Controls::InkCanvasSelectionChangingEventArgs
System.Windows.Controls::InkCanvasSelectionEditingEventArgs
System.Windows.Controls::InkCanvasStrokeErasingEventArgs
System.Windows.Forms::BindingCompleteEventArgs
System.Windows.Forms::ColumnReorderedEventArgs
System.Windows.Forms::ColumnWidthChangingEventArgs
System.Windows.Forms::DataGridViewCellCancelEventArgs
System.Windows.Forms::DataGridViewCellValidatingEventArgs
System.Windows.Forms::DataGridViewRowCancelEventArgs
System.Windows.Forms::FormClosingEventArgs
System.Windows.Forms::InputLanguageChangingEventArgs
System.Windows.Forms::PopupEventArgs
System.Windows.Forms::SplitterCancelEventArgs
System.Windows.Forms::TabControlCancelEventArgs
System.Windows.Forms::ToolStripDropDownClosingEventArgs
System.Windows.Forms::TreeViewCancelEventArgs
System.Windows.Forms::WebBrowserNavigatingEventArgs
System.Windows.Navigation::NavigatingCancelEventArgs
System.Windows::SessionEndingCancelEventArgs

