如何告诉我的程序它应该继续从数字中减去？

Question

我有以下代码：

public partial class MainWindow : Window 
{ 
    public MainWindow() 
    { 
     InitializeComponent(); 
    } 

    double salaryAmount; 
    double subtractAmount; 
    double newSalaryAmount; 
    string amountBackToString; 

    private void Button1_Click(object sender, RoutedEventArgs e) 
    { 
     try 
     { 
      salaryAmount = double.Parse(TextBox1.Text); 
      label1.Content = salaryAmount.ToString(); 
     } 
     catch (Exception) 
     { 

      MessageBox.Show("This was not a valid input."); 
     } 
    } 

    private void Button2_Click(object sender, RoutedEventArgs e) 
    { 
     try 
     { 
      subtractAmount = double.Parse(TextBox2.Text); 
      newSalaryAmount = salaryAmount - subtractAmount; 
      label1.Content = newSalaryAmount.ToString(); 
     } 
     catch (Exception) 
     { 
      MessageBox.Show("This was not a valid input."); 
     } 
    } 

    private void Button3_Click(object sender, RoutedEventArgs e) 
    { 
     amountBackToString = Convert.ToString(newSalaryAmount); 
     string[] currentAmount = { amountBackToString }; 
     File.WriteAllLines(@"C:\Users\Silas\Downloads\Lohn.txt", currentAmount); 
    } 

    private void Button4_Click(object sender, RoutedEventArgs e) 
    { 
     string text = File.ReadAllText(@"C:\Users\Silas\Downloads\Lohn.txt"); 
     label1.Content = text; 
     salaryAmount = Convert.ToDouble(label1.Content); 
    } 
} 

的问题是，它的初始输入每次重置数，然后减去但它应该采取一个初始输入和离它

我的计划中减去是一个工资计算器。

Answer 1

您只需将newSalaryAmount应用到当前salaryAmount

private void Button2_Click(object sender, RoutedEventArgs e) 
{ 
    try 
    { 
     subtractAmount = double.Parse(TextBox2.Text); 
     newSalaryAmount = salaryAmount - subtractAmount; 

     //Set the new current salary 
     salaryAmount = newSalaryAmount 
     label1.Content = newSalaryAmount.ToString(); 
    } 
    catch (Exception) 
    { 
     MessageBox.Show("This was not a valid input."); 
    } 
} 

在你的情况salaryAmount总是远离TextBox1.Text给出的初始值，所以当你会去再次降低值它会采用自那以后没有改变的价值。