3 private void equalsButton_Click( object sender, RoutedEventArgs e) { calculateResult(); }

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6 private void firstNumberTextBox_TextChanged( object sender,TextChangedEventArgs e) { calculateResult(); }

7 string oldFirstNumber = ""; private void firstNumberTextBox_TextChanged( object sender, TextChangedEventArgs e) { if (firstNumberTextBox.Text == oldFirstNumber) return; oldFirstNumber = firstNumberTextBox.Text; calculateResult(); }

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13 public class AdderClass { private int topValue; public int TopValue { get { return topValue; } set { topValue = value; } } // repeat for bottomValue public int AnswerValue { get { return topValue + bottomValue;} } }

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15 public interface INotifyPropertyChanged { // Summary: // Occurs when a property value changes. event PropertyChangedEventHandler PropertyChanged; }

16 PropertyChanged(this, new PropertyChangedEventArgs("AnswerValue"));

17 public int AnswerValue { get { return topValue + bottomValue; } }

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19 xmlns:local="clr-namespace:AddingMachine"

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