ICommandHandler.CanHandleCommand(ReportCommand, ref Boolean) Method

Indicates whether or not the specified End-User Designer command can be handled.

Namespace: DevExpress.XtraReports.UserDesigner

Assembly: DevExpress.XtraReports.v20.2.Extensions.dll

NuGet Package: DevExpress.Win.Reporting

Declaration

C#

bool CanHandleCommand(
    ReportCommand command,
    ref bool useNextHandler
)

VB.NET

Function CanHandleCommand(
    command As ReportCommand,
    ByRef useNextHandler As Boolean
) As Boolean

Parameters

Name	Type	Description
command	ReportCommand	A ReportCommand enumeration value that specifies the command.
useNextHandler	Boolean	true to allow calling the next handler registered for this command; otherwise false.

Returns

Type	Description
Boolean	true, if the command can be handled; otherwise, false.

Remarks

The useNextHandler parameter determines whether or not to invoke the next handler for the current command. This allows you to define multiple command handlers for a single command, as well as to control which handlers to invoke.

When useNextHandler is disabled, the next handler (the default one, in the following example) is not invoked. And, because useNextHandler is always set to false (False in Visual Basic), with no regard to the command in question, this means that the default handler will not be invoked for any command.

The following code illustrates this behavior: the Delete command will always be handled, with no regard to the conditions specified in the ICommandHandler.HandleCommand method body. As a result, you are not permitted to delete report bands, for example.

C#

public bool CanHandleCommand(ReportCommand command, ref bool useNextHandler) {
    useNextHandler = command != ReportCommand.Delete;
    return command == ReportCommand.Delete;
}

VB.NET

Public Function CanHandleCommand(command As ReportCommand, ByRef useNextHandler As Boolean) As Boolean
    useNextHandler = command <> ReportCommand.Delete
    Return command = ReportCommand.Delete
End Function

In turn, the ICommandHandler.HandleCommand method is called only when the CanHandleCommand method returns true (True in Visual Basic), which means that all logical conditions should be evaluated with the CanHandleCommand method body.