how to update a table in sqlite corresponding to a id - xamarin

Question

i have 2 forms. first form saves value to company_master except 2 fields.In second form want to update company_master in sqlite when id=1 those 2 fileds.
in form2 i have tried simple update but it doesnot work
form1.xaml
private async void OnSave(object sender, EventArgs e)
{
try
{
if (string.IsNullOrWhiteSpace(ECompnyPhone.Text))
{
}
else
{
if (pickCompnyType.SelectedIndex == 0)
{
type = "Academic";
}
else if (pickCompnyType.SelectedIndex == 1)
{
type = "Financial";
}
if (pickYear.SelectedIndex == 0)
{
year = "April - March";
}
else if (pickYear.SelectedIndex == 1)
{
year = "January - December";
}
var cmpny = new COMPANY_MASTER
{
Name = ECompnyName.Text,
PhoneNo = ECompnyPhone.Text,
Email = ECompnyEmail.Text,
Address1 = ECompnyAdd1.Text,
Address2 = ECompnyAdd2.Text,
Address3 = ECompnyAdd3.Text,
Type = type,
Wing = EWing.Text,
Year = year
};
var checker = await _connection.InsertAsync(cmpny);
if (checker == 1)
{
await DisplayAlert("Message", "Data saved successfully.", "Ok");
await Navigation.PopAsync();
}
}
}
catch
{
await DisplayAlert("Error", "Error in data saving. Please retry later.", "Ok");
}
}
form2.xaml
private async void OnSave(object sender, EventArgs e)
{
try
{
var expense = new COMPANY_MASTER
{
Opening_Cash = Convert.ToDecimal(EOCash.Text),
Available_Cash = Convert.ToDecimal(EACash.Text)
};
var checker = await _connection.UpdateAsync(expense);
if (checker == 1)
{
await DisplayAlert("Message", "Data saved successfully.", "Ok");
await Navigation.PopAsync();
}
}
catch
{
await DisplayAlert("Error", "Error in data saving. Please retry later.", "Ok");
}
}
Company_master.cs
public class COMPANY_MASTER : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
[PrimaryKey, AutoIncrement]
public int CompanyId { get; set; }
public string _name { get; set; }
public string _address1 { get; set; }
public string _address2 { get; set; }
public string _address3 { get; set; }
public string _email { get; set; }
public string _phoneNo { get; set; }
public string _type { get; set; }
public string _wing { get; set; }
public string _year { get; set; }
public decimal _openingcash { get; set; }
public decimal _availablecash { get; set; }
public decimal Available_Cash
{
get { return _availablecash; }
set
{
if (_availablecash == value)
return;
_availablecash = value;
OnPropertyChanged();
}
}
public decimal Opening_Cash
{
get { return _openingcash; }
set
{
if (_openingcash == value)
return;
_openingcash = value;
OnPropertyChanged();
}
}
public string Name
{
get { return _name; }
set
{
if (_name == value)
return;
_name = value;
OnPropertyChanged();
}
}
public string Year
{
get { return _year; }
set
{
if (_year == value)
return;
_year = value;
OnPropertyChanged();
}
}
public string Wing
{
get { return _wing; }
set
{
if (_wing == value)
return;
_wing = value;
OnPropertyChanged();
}
}
public string Type
{
get { return _type; }
set
{
if (_type == value)
return;
_type = value;
OnPropertyChanged();
}
}
public string PhoneNo
{
get { return _phoneNo; }
set
{
if (_phoneNo == value)
return;
_phoneNo = value;
OnPropertyChanged();
}
}
public string Address1
{
get { return _address1; }
set
{
if (_address1 == value)
return;
_address1 = value;
OnPropertyChanged();
}
}
public string Address2
{
get { return _address2; }
set
{
if (_address2 == value)
return;
_address2 = value;
OnPropertyChanged();
}
}
public string Address3
{
get { return _address3; }
set
{
if (_address3 == value)
return;
_address3 = value;
OnPropertyChanged();
}
}
public string Email
{
get { return _email; }
set
{
if (_email == value)
return;
_email = value;
OnPropertyChanged();
}
}
private void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
i want to update company_master's opening_cash and available_cash where companyid=1 in form2
now updation is not working

Answer 1

You can't update a new element
var expense = new COMPANY_MASTER
{
Opening_Cash = Convert.ToDecimal(EOCash.Text),
Available_Cash = Convert.ToDecimal(EACash.Text)
};
var checker = await _connection.UpdateAsync(expense); //here expense.companyid = 0
...
when you create a new object id is asigned with 0 value, for update id must exist in your table.