/// <summary>
/// Gets a device capability represented as an array
/// </summary>
/// <param name="capability">Capability to retrieve</param>
/// <returns>value of capability specified in capability argument</returns>
private T[] GetArrayCapability <T>(DeviceCapability capability, ReadArray <T> readArray, int itemByteSize)
{
uint numOutputs = UnsafeNativeMethods.DeviceCapabilitiesW(this._deviceName, this._portName, capability, SafeMemoryHandle.Null, this._devMode);
if (numOutputs < 1)
{
return(Array.Empty <T>());
}
HGlobalBuffer buffer = new HGlobalBuffer((int)(numOutputs * itemByteSize));
try
{
numOutputs = UnsafeNativeMethods.DeviceCapabilitiesW(this._deviceName, this._portName, capability, buffer.Handle, this._devMode);
if (numOutputs >= 0)
{
return(readArray(buffer, itemByteSize));
}
}
finally
{
buffer.Release();
}
return(null);
}
/// <summary>
/// Gets a device capability represented as an array
/// </summary>
/// <typeparam name="T">Capability item type</typeparam>
/// <param name="capability">Capability to retrieve</param>
/// <param name="readItem">Delegate to marshal a single capability item from unmanaged memory</param>
/// <returns>An array of capabilities specified by the capability arg or null if the call fails</returns>
private T[] GetArrayCapability <T>(DeviceCapability capability, ReadArray <T> readItem) where T : struct
{
return(GetArrayCapability <T>(capability, readItem, Marshal.SizeOf(typeof(T))));
}
