/// <summary>
/// Gets a <see cref="DescriptorType.String"/> descriptor from the device.
/// </summary>
/// <param name="stringData">Buffer to store the returned string in upon success.</param>
/// <param name="langId">The language ID to retrieve the string in. (0x409 for english).</param>
/// <param name="stringIndex">The string index to retrieve.</param>
/// <returns>True on success.</returns>
public bool GetString(out string stringData, short langId, byte stringIndex)
{
stringData = null;
int iTransferLength;
LangStringDescriptor sd = new LangStringDescriptor(255);
bool bSuccess = GetDescriptor((byte) DescriptorType.String, stringIndex, langId, sd.Ptr, sd.MaxSize, out iTransferLength);
if (bSuccess && iTransferLength > UsbDescriptor.Size && sd.Length == iTransferLength)
bSuccess = sd.Get(out stringData);
else if (!bSuccess)
UsbError.Error(ErrorCode.Win32Error, Marshal.GetLastWin32Error(), "GetString:GetDescriptor", this);
else
stringData = String.Empty;
return bSuccess;
}
/// <summary>
/// Asking for the zero'th index is special - it returns a string
/// descriptor that contains all the language IDs supported by the
/// device. Typically there aren't many - often only one. The
/// language IDs are 16 bit numbers, and they start at the third byte
/// in the descriptor. See USB 2.0 specification, section 9.6.7, for
/// more information on this.
/// </summary>
/// <returns>A collection of LCIDs that the current <see cref="UsbDevice"/> supports.</returns>
public bool GetLangIDs(out short[] langIDs)
{
LangStringDescriptor sd = new LangStringDescriptor(UsbDescriptor.Size + (16*sizeof (short)));
int ret;
bool bSuccess = GetDescriptor((byte) DescriptorType.String, 0, 0, sd.Ptr, sd.MaxSize, out ret);
if (bSuccess && ret == sd.Length)
{
bSuccess = sd.Get(out langIDs);
}
else
{
langIDs = new short[0];
UsbError.Error(ErrorCode.Win32Error, Marshal.GetLastWin32Error(), "GetLangIDs", this);
}
sd.Free();
return bSuccess;
}
