Saving a list with SQL - sqlite

Question

I have an Entry, A save button and a list view. when a user add an entry to this list how can I save this with SQL so next time I come back to the app, the List is not resets. I have create a Model and a view model for this Job.
public class Energys
{
public int Id { get; set; }
public string EE {get; set;}
}
and view model
class Viewmodel
{
public ICommand AddEnergyCommand => new Command(AddEnergy);
public IList<Energys> energy { get; set; }
public Viewmodel()
{
try
{
energy = new ObservableCollection<Energys>();
energy.Add(new Energys { Id = 1, EE = "6 MV" });
energy.Add(new Energys { Id = 2, EE = "10 MV" });
}
catch (Exception ex)
{
}
}
public void AddEnergy()
{
energy.Add(new Energys { Id = 3, EE = "15 MV" });
}
}
I know working with Sql is not simple but ....
so how can I save all energys by AddEnergycomamnd for all time.

Answer 1

From Store data in a local SQLite.NET database, if you want to insert data in sqlite database, you need to install sqlite-net-pcl by nuget package.
Then creating model, the ID property is marked with PrimaryKey and AutoIncrement attributes to ensure that each Energys instance in the SQLite.NET database will have a unique id provided by SQLite.NET.
public class Energys
{
[PrimaryKey, AutoIncrement]
public int Id { get; set; }
public string EE { get; set; }
}
Finally, you need to connect sqlite database, and create table.
public partial class Page4 : ContentPage
{
public SQLiteConnection conn;
public ICommand AddEnergyCommand => new Command(AddEnergy);
public ICommand CreateEnergyCommand => new Command(CreateTable);
private ObservableCollection<Energys> _energy;
public ObservableCollection<Energys> energy
{
get { return _energy; }
set
{
_energy = value;
OnPropertyChanged("energy");
}
}
public Page4()
{
InitializeComponent();
conn = GetSQLiteConnection();
CreateTable();
energy = new ObservableCollection<Energys>(conn.Table<Energys>().ToList());
this.BindingContext = this;
}
public SQLiteConnection GetSQLiteConnection()
{
var fileName = "Energys.db";
var documentPath = System.Environment.GetFolderPath(System.Environment.SpecialFolder.LocalApplicationData);
var path = Path.Combine(documentPath, fileName);
var connection = new SQLiteConnection(path);
return connection;
}
private void AddEnergy()
{
Energys e = new Energys();
e.EE = entry1.Text;
var data = conn.Table<Energys>();
var result = conn.Insert(e);
if (result > 0)
{
Console.WriteLine("Sucessfully Added");
}
else
{
Console.WriteLine("Already energy id Exist");
}
energy = new ObservableCollection<Energys>(conn.Table<Energys>().ToList());
entry1.Text = "";
}
private void CreateTable()
{
conn.CreateTable<Energys>();
}
}
<StackLayout>
<Entry x:Name="entry1" />
<StackLayout Orientation="Horizontal">
<Button
x:Name="btncreate"
Command="{Binding CreateEnergyCommand}"
Text="create table" />
<Button
x:Name="btnsave"
Command="{Binding AddEnergyCommand}"
Text="save data" />
</StackLayout>
<ListView HasUnevenRows="True" ItemsSource="{Binding energy}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label Text="{Binding EE}" />
<Label Text="{Binding Id}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
Update:
About delete item from sqlite database, you can get ListView selected item, then delete this item from sqlite database.
private Energys _selecteditem;
public Energys selecteditem
{
get { return _selecteditem; }
set
{
_selecteditem = value;
OnPropertyChanged("selecteditem");
}
}
<ListView
HasUnevenRows="True"
ItemsSource="{Binding energy}"
SelectedItem="{Binding selecteditem}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout>
<Label Text="{Binding EE}" />
<Label Text="{Binding Id}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
public ICommand DeleteEnergyCommand => new Command(DeleteEnergy);
private void DeleteEnergy()
{
if(selecteditem!=null)
{
conn.Delete(selecteditem);
}
energy = new ObservableCollection<Energys>(conn.Table<Energys>().ToList());
}