Plug and Play XML Configuration
2/27/2008
Although the Plug and Play hardware ID should generally be specified using the HardwareId property within the Service Object source code, there may be times when Service Object vendors require more flexibility. For example, the hardware ID needs to be changed without redistributing the entire Service Object assembly.
To support these cases, POS for .NET specifies hardware associations in an XML file. These XML files are read from the directory that is specified in the registry key HKEY_LOCAL_MACHINE/SOFTWARE/POSfor.NET/ControlConfigs. When constructing the list of available Service Objects and devices, PosExplorer processes each file in that directory and associates the device where possible. No additional action is required by either the Service Object or the application.
Schema
A Plug and Play configuration file must begin with a top-level node named PointOfServiceConfig and have the attribute Version to indicate the XML version of the file.
Following that, there may be any number of ServiceObject subnodes. Each service object node must include Type and Name attributes to indicate the POS device type and name of the Service Object. These two fields will be matched against available Service Objects to determine which, if any, should be associated with devices specified in the subnode HardwareId. There is also an optional attribute on the ServiceObject node, Override. If this attribute is set, then the device associations in the XML file overrides those contained in the assembly.
The ServiceObject node contains subnodes with the name HardwareId, which have From and To attributes. The contents of these attributes are the same as would be found in the HardwareId attribute in a Service Object assembly and specify the range of hardware IDs to associate with the Service Object.
Example
The example shows a typical XML Plug and Play configuration file.
<PointOfServiceConfig Version="1.0">
<ServiceObject Type="Msr" Name="ExampleMsr" Override="yes">
<HardwareId From="HID\Vid_0801&Pid_0002&Rev_0100"
To="HID\Vid_0801&Pid_0002&Rev_9999" />
</ServiceObject>
</PointOfServiceConfig>
Hardeware ID Precedence
If the Override attribute on the ServiceObject node is set, then the device association specified in the XML takes precedence, and any HardwareId attribute on the Service Object will be discarded.
If the Override attribute is not set, then neither the XML nor the HardwareId has precedence. Instead, PosExplorer associates the union of all specified devices with the Service Object.