Populate SQLite database from generic "list of items" - xamarin

Question

I use a SQLite database to populate a listview with a generic list of TodoItems:
ListView.ItemsSource = await App.Database.GetItemsAsync("SELECT * FROM [TodoItem]");
I can read data of the same kind from a database source using the HttpClient class as well via
public async Task<List<TodoItem>> ReadDataAsync ()
....
Items = new List<TodoItem> ();
....
var content = await response.Content.ReadAsStringAsync ();
Items = JsonConvert.DeserializeObject <List<TodoItem>> (content);
....
return Items;
whereafter I can use this as a data source as well:
ListView.ItemsSource = await App.ReadDataAsync();
Both ways work well.
What I want now is combine both routines to accomplish a code which checks whether we have an online connection, if yes, drop the database and populate it using the result of ReadDataAsync from above, if no, leave the database alone.
I found no way to directly assign a List to my database, overwriting the whole contents, I think of something like:
App.Database.Items = await App.ReadDataAsync();
but SQLite doesn't seem to expose the data store directly. How can I accomplish this?

Answer 1

For android for example, you could try: There's no need to drop the database.
//Check for internet connection
var connectivityManager =
(ConnectivityManager)this.GetSystemService("connectivity");
var activeConnection = connectivityManager.ActiveNetworkInfo;
if ((activeConnection != null) && activeConnection.IsConnected)
{
//Make call to the API
var list = await App.ReadDataAsync();
//Update or Insert local records
foreach (var item in list)
{
var success = UpdateOrInsert(item);
//Do something after - like retry incase of failure
}
}
The UpdatedOrInsert method can look like:
private bool UpdateOrInsert(TodoItem item)
{
var rowsAffected = App.Database.Update(item);
if (rowsAffected == 0)
{
// The item doesn't exist in the database, therefore insert it
rowsAffected = App.Database.Insert(item);
}
var success = rowsAffected > 0;
return success;
}