Data binding for 20 <inputs> but only one common onchange-method - .net-core

Question

I have a calculation sheet where the user can enter several positions (basic price, multiple options) that should be added up to a total. I am struggling in binding the events to add up all the positions to a final total. The problem is, that the #bind="" does not allow me to call one onchange events for every input, hence I would have to implement one event handler per position (circa 20 in total).
<input type="number" #bind="calc.BasicPrice" class="form-control" />
<input type="number" #bind="calc.Option" class="form-control" />
<input type="number" #bind="calc.Total" class="form-control" readonly/>
#code
{
private CalculationModel calc = new CalculationModel();
}
What I have tried so far is to bind a UpdateBottomLine() method to the input onchange events like that:
<input type="number" value="#calc.BasicPrice"
#onchange="(e) => CalculateBottomLines(calc.BasicPrice.GetType(), e)"
class="form-control" />
#code {
private void CalculateBottomLines(Type field, ChangeEventArgs input)
{
input.Value = input.Value.ToString().Replace(".", ",");
// Update the input variable
calc.BasicPrice = Convert.ToDecimal( input.Value.ToString() ); // <-- The name of the receiving variable has to be determined dynamically, depending on the field that was changed
// Update the total
calc.Total = calc.BasicPrice + calc.Option;
}
}
Now unfortunately, while this changes my total when i change the basic price, this does not yet work dynamically but is only implemented for the basic price. I would need a solution where I can pass a reference to the field that was changed to the CalculateBottomLines() method.

Answer 1

Here I am using the property setter to recalculate the total and #bind:event="oninput" to trigger on input.
<input type="number" #bind="calc.BasicPrice" #bind:event="oninput" class="form-control" />
<input type="number" #bind="calc.Option" #bind:event="oninput" class="form-control" />
<input type="number" #bind="calc.Total" class="form-control" readonly />
#code {
SomeModel calc = new SomeModel();
public class SomeModel
{
public double BasicPrice
{
get => basicPrice;
set { basicPrice = value; UpdateTotal(); }
}
public double Option
{
get => option;
set { option = value; UpdateTotal(); }
}
public double Total { get; set; }
internal void UpdateTotal()
{
Total = BasicPrice + Option;
}
private double basicPrice;
private double option;
}
}