PosCommon Class (POS for .NET v1.12 SDK Documentation)

2/27/2008

PosCommon is the Base class for all specific Interface classes, and all Service Objects indirectly derive from it. PosCommon defines the common properties, methods, and events that the Unified Point of Service (UPOS) specification requires in all device classes.

PosCommon Properties

The following table describes the properties of the PosCommon class available to POS applications.

Property	Type	Description
CapCompareFirmwareVersion	bool	Indicates whether the Service Object and device supports comparing the firmware version in the physical device against that of a firmware file.
CapPowerReporting	PowerReporting enum	Indicates the power reporting capabilities of the device.
CapStatisticsReporting	bool	Indicates whether the device can accumulate and can provide various statistics regarding usage.
CapUpdateStatistics	bool	If set to true, some or all of the device statistics can be reset to 0 (zero) using the ResetStatistic method for one update and ResetStatistics method for a list of updates, or updated using the UpdateStatistic method for one update and the UpdateStatistics method for a list of updates with the corresponding specified values.
CapUpdateFirmware	bool	Indicates whether the device's firmware can be updated via the UpdateFirmware method.
CheckHealthText	string	Indicates the health of the device.
Claimed	bool	Indicates whether the device is claimed for exclusive access.
DeviceDescription	string	Holds a string identifying the device and the company that manufactured it.
DeviceEnabled	bool	Indicates whether the device is in an operational state.
DeviceName	string	UPOS calls it PhysicalDeviceName; OPOS calls it DeviceName.
DevicePath	string	Set by POS for .NET for Plug and Play devices. For non-Plug and Play devices, DevicePath can be assigned using a configuration file.
FreezeEvents	bool	When set to true, the application has requested that the Service Object not deliver events.
PowerNotify	PowerNotification enum	Holds the type of power notification selection made by the application.
PowerState	PowerState enum	Holds the current power condition.
ServiceObjectDescription	string	Identifies the Service Object supporting the device and the company that produced it. This property is listed as DeviceServiceDescription in the UPOS specification.
ServiceObjectVersion	System.Version	Holds the Service Object version number. This property is listed as DeviceServiceVersion in the UPOS specification.
State	ControlState enum	Holds the current state of the device.
SynchronizingObject	ISynchronizeInvoke	Gets or sets the marshalling object for event handler calls from a POS event.

PosCommon Methods

The following table describes the methods of the PosCommon class available to applications.

Method	Return Type	Description
CheckHealth	string	Performs a health check on the device. The type of check to be performed is indicated by the HealthCheckLevel parameter. The method also updates the CheckHealthText property.
Claim	void	Requests exclusive access to the device. Service Object writers are advised to only throw exceptions in unexpected conditions; for example, OutOfMemory. Otherwise, Service Objects should return True if the device was claimed and False if a time-out occurred.
Close	void	Releases the device and its resources.
CompareFirmwareVersion	CompareFirmwareResult	Determines whether the version of the specified firmware is newer than, older than, or the same as the version of firmware in the physical device.
DirectIO	DirectIOData	Used to communicate directly with the Service Object. In the UPOS specification, it has two in/out parameters. As used by POS for .NET, this method returns a structure and no in/out parameters.
Open	void	Opens a device for subsequent input/output processing.
Release	void	Releases exclusive access to the device.
ResetStatistic	void	Resets the specified statistic to zero. Used in POS for .NET for operations on a single statistic.
ResetStatistics	void	Resets all statistics for a specified category to 0 (zero).
ResetStatistics	void	Resets the specified statistics to 0 (zero).
ResetStatistics	void	Resets all statistics associated with a device to 0 (zero).
RetrieveStatistic	string	Retrieves the specified device statistic. Used in POS for .NET for operations on a single statistic.
RetrieveStatistics	string	Retrieves all device statistics.
RetrieveStatistics	void	Retrieves the statistics for the specified category.
RetrieveStatistics	void	Retrieves the specified statistics.
UpdateFirmware	void	Updates the firmware of a device with the version of the firmware contained in the specified filename.
UpdateStatistic	void	Updates a statistic. Added to POS for .NET for operations on a single statistic.
UpdateStatistics	void	Updates a list of statistics with the corresponding specified values.
UpdateStatistics	void	Updates the specified category of statistics with the specified value.

PosCommon Events

The following table describes the PosCommon class events.

Method	Description
DirectIOEvent	Raised by the Service Object to communicate information directly to the application.
StatusUpdateEvent	Raised by the Service Object to alert the application of a device status change.

Example

The following code example demonstrates how to use the properties and methods common to all Service Objects to display information about a connected device.

    // Create a dervied class of PosCommon
    public class PosCommonSample: PosCommon
    {
        // Implement all base methods and properties.
        // ...                
    }

    // Create instances for the example.
    PosExplorer explorer = new PosExplorer();
    PosCommonSample pcs = new PosCommonSample();
    DeviceInfo device = explorer.GetDevice("MSR");
    pcs = (PosCommonSample)explorer.CreateInstance(device);
                
    // Open and claim the device, then print information
    // about the device to the console.
    pcs.Open();
    pcs.Claim(1000);
    Console.WriteLine("Name: {0}", pcs.DeviceName);
    Console.WriteLine("Description: {0}", pcs.DeviceDescription);
    Console.WriteLine("Path: {0}", pcs.DevicePath);
    Console.WriteLine("Enabled: {0}", pcs.DeviceEnabled);

    pcs.Close();

See Also

Concepts

POS for .NET Class Tree