How to manage textbox changes when building complicated financial calculation in WPF

Question

I am building a wpf application for some complicated financial calculation using textbox. The spreadsheet example

All grey cells are based on the formula.

I know I can use textbox_textChanges to track single textbox change, I tried to create some general textchange Method like the below:

    private void Txt_onTextChanged(object sender, TextChangedEventArgs e)
    {
        textbox.Text = int.Parse(!string.IsNullOrEmpty(textbox1.Text) ? textbox1.Text : "0") +
                       int.Parse(!string.IsNullOrEmpty(textbox1.Text) ? textbox1.Text : "0")
    }

It doesn't work well since I have so many different textboxes and calculations. (When the interest Basis changed, 3 more cells are changed) Is there an efficient way to track those changes and automatically reflect on the other textbox? I don't want to create text_TextChanges for eahch single Textbox, and the calculation method is not the same.

Answer 1

Finally I found a way to realize those functions. Using Converter.

   public class AddListRecordsConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            decimal val = 0;
            decimal result = 0;

            foreach (var txt in values)
            {
                if (string.IsNullOrEmpty(txt.ToString())) continue;
                if (decimal.TryParse(txt.ToString(), out val))
                    result += val;
                else
                    return "$0.00";
            }

            return result.ToString();
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

public class InterestCalculationRecordsConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
        {
            decimal val = 0;
            decimal result = 0;
            List<decimal> convertedLists = new List<decimal>();
            foreach (var txt in values)
            {
                if (string.IsNullOrEmpty(txt.ToString())) return null;
                if (decimal.TryParse(txt.ToString(), out val))
                    //result += val;
                    convertedLists.Add(val);
                else
                    return "$0.00";
            }

            if (convertedLists[0] == 0) return 0;
            result = 1 / convertedLists[0] * convertedLists[1] * convertedLists[2] * convertedLists[3];

            return result.ToString();
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

Xaml is like below.

 <Page.Resources>
        <local:AddListRecordsConverter x:Key="AddListRecordsConverter"></local:AddListRecordsConverter>
        <local:InterestCalculationRecordsConverter x:Key="InterestCalculationRecordsConverter"></local:InterestCalculationRecordsConverter>
 </Page.Resources>

Textbox Xaml is like below (just post the int calculate):

<TextBox Grid.Row="7" Grid.Column="2" Name="TxtPostJudgmentInterest" IsEnabled="False">
    <TextBox.Text>
        <MultiBinding Converter="{StaticResource InterestCalculationRecordsConverter}">
            <Binding ElementName="TxtYearDays" Path="Text" Mode="OneWay"></Binding>
            <Binding ElementName="TxtDays" Path="Text" Mode="OneWay"></Binding>
            <Binding ElementName="TxtPrincipal" Path="Text" Mode="OneWay"></Binding>
            <Binding ElementName="TxtInt" Path="Text" Mode="OneWay"></Binding>
        </MultiBinding>
    </TextBox.Text>
</TextBox>