public static BitmapImageExpressionResult DeviceModelImage(DeviceModel DeviceModel)
{
if (DeviceModel == null)
throw new ArgumentNullException("DeviceModel");
using (Stream deviceModelImage = DeviceModel.Image())
{
if (deviceModelImage == null)
return null;
else
return ImageFromStream(deviceModelImage);
}
}
public static Tuple<DeviceModel, bool> GetOrCreateDeviceModel(this DbSet<DeviceModel> DeviceModelsSet, string Manufacturer, string Model, string ModelType)
{
if (string.IsNullOrWhiteSpace(Manufacturer))
Manufacturer = "Unknown";
else
Manufacturer = Manufacturer.Trim();
if (string.IsNullOrWhiteSpace(Model))
Model = "Unknown";
else
Model = Model.Trim();
if (string.IsNullOrWhiteSpace(ModelType))
ModelType = null;
else
ModelType = ModelType.Trim();
// Already Exists?
var deviceModel = DeviceModelsSet.FirstOrDefault(dm => dm.Manufacturer == Manufacturer && dm.Model == Model);
if (deviceModel == null)
{
// Ensure only one thread/request at a time
lock (_CreateDeviceModelLock)
{
// Check again now that lock is enforced
deviceModel = DeviceModelsSet.FirstOrDefault(dm => dm.Manufacturer == Manufacturer && dm.Model == Model);
if (deviceModel == null)
{
// Create the Device Model in a different DataContext so we don't have to commit unrelated changes
using (DiscoDataContext database = new DiscoDataContext())
{
var description = $"{Manufacturer} {Model}";
if (Model.Equals("Unknown", StringComparison.OrdinalIgnoreCase))
{
description = $"Unknown {Manufacturer} Model";
}
var addDeviceModel = new DeviceModel
{
Manufacturer = Manufacturer,
Model = Model,
ModelType = ModelType,
Description = description
};
database.DeviceModels.Add(addDeviceModel);
database.SaveChanges();
}
// Obtain the Device Model with the in-scope DataContext
// - Overhead acknowledged, but reasonable given the infrequency of occurrence
deviceModel = DeviceModelsSet.FirstOrDefault(dm => dm.Manufacturer == Manufacturer && dm.Model == Model);
return new Tuple<DeviceModel, bool>(deviceModel, true);
}
}
}
else
{
if (deviceModel.ModelType != ModelType)
deviceModel.ModelType = ModelType;
}
return new Tuple<DeviceModel, bool>(deviceModel, false);
}
