IDSFDevice::Next Property

项目
09/21/2010

The Next property gets or sets the next device in a chain.

This property is read/write.

Syntax

HRESULT put_Next(
  [in]           DSFDevice *pDSFDevice
);

HRESULT get_Next(
  [out, retval]  DSFDevice **ppDSFDevice
);

Property Value

An interface pointer to the device to follow this device in the chain.

Error Codes

Next returns one of the following values:

Name	Meaning
S_OK	The operation succeeded.
E_POINTER	The ppDSFDevice parameter was not a valid pointer.
E_NOINTERFACE	The pDSFDevice parameter is not a valid DSFDevice object.

Remarks

The Next property is reserved for future use and is included for completeness.

You can use this property to chain devices that process data serially (similar to Microsoft Windows Driver Model [WDM] device stacks).

Examples

The following VBScript code example shows how to get and set a Next property.

Dim SoftUSBDevice1 
Dm SoftUSBDevice2

Set SoftUSBDevice1 = CreateObject("SOFTUSB.SoftUSBDevice")
Set SoftUSBDevice2 = CreateObject("SOFTUSB.SoftUSBDevice")

Dim DSFDevice1 : Set DSFDevice1 = SoftUSBDevice1.DSFDevice
Dim DSFDeivce2 : Set DSFDevice2 = SoftUSBDevice2.DSFDevice

DSFDevice1.Next = DSFDevice2

Dim DSFDeviceCheck

DSFDeviceCheck = DSFDevice2.Next

If DSFDeviceCheck <> DSFDevice2 Then
 WScript.StdOut.WriteLine "DSFDevice Next returned incorrect value"
EndIf