/// <summary>
/// <para>
/// If any <see cref="DBSet{T}"/> belonging to this <see cref="DBContext"/> has any significant changes within the data.
/// This function will commit those changes to the database.
/// </para>
/// </summary>
/// <returns></returns>
public async Task Commit()
{
await Task.Run(async() =>
{
// Check if any changes have happened
if (!ChangeTracker.Instance.DetectChanges(this))
{
return;
}
// Get all the changes
while (ChangeTracker.Instance.Changes.Count > 0)
{
// Get the DBChange
var change = ChangeTracker.Instance.Changes.Dequeue();
// Run the action provided by the DBChange from the changetracker
await DBActionProvider.RunAction(change.Action, change.Value, Schema);
}
});
}
/// <summary>
/// Gets the database data
/// </summary>
/// <returns></returns>
private async Task GetDatabaseData()
{
await Task.Run(() =>
{
// Iterate over every property in the DBContext
foreach (var prop in GetType().GetProperties())
{
// Check to see if the property type has any generic arguments
// The dbsets always need a generic argument and that's what we're trying to get
if (prop.PropertyType.GetGenericArguments().Length < 1)
{
continue;
}
// Get the generic type (always should be just 1)
Type genericType = prop.PropertyType.GetGenericArguments().FirstOrDefault();
// Check to see if the property was of type DBSet<genericType>
if (!(prop.PropertyType == typeof(DBSet <>).MakeGenericType(genericType)))
{
continue;
}
MethodInfo genMethod;
try
{
// Get the fetch method
var method = DBActionProvider.GetType().GetMethod(nameof(DBActionProvider.Fetch));
// Generate the fetch method with the generic type we got earlier
genMethod = method.MakeGenericMethod(genericType);
}
catch (Exception ex)
{
throw new DBAccessException("Could not instantiate the Fetch method", ex);
}
// create a task to execute the method
object t = null;
try
{
// Execute the generic fetch method for the specified type
var p = typeof(Task <>).MakeGenericType(typeof(DBSet <>).MakeGenericType(prop.PropertyType.GetGenericArguments().First()));
t = Convert.ChangeType(genMethod.Invoke(DBActionProvider, new object[] { null }), p);
}
catch (Exception ex)
{
throw new DBAccessException("Could not generate the task to execute the Fetch method", ex);
}
// The value
object value;
try
{
// Get the database values
value = t.GetType().GetProperty("Result")?.GetValue(t);
}
catch (Exception ex)
{
throw new DBAccessException("The result from the Fetch method could not be retrieved", ex);
}
try
{
// Set the remote values to the ordinary list of the dbset
prop.SetValue(this, value);
}
catch (Exception ex)
{
throw new DBAccessException($"Could not set the {prop.Name} to the result from the Fetch function", ex);
}
}
});
}
