Question

我正在处理这个获取用户输入的应用程序，并将它们放入ListBox中，并找到这些数字的总和（一切正常）。我的问题是，每次用户输入一个新号码，该号码正在窗口中显示（我不想要），而我只想在窗口上显示所有ListBox号码的当前总和。因此，如果用户输入新号码，则应在窗口上显示新的总和。请帮我。非常感谢你的进步。这是我的代码运行得很好....

    private void ClickToAddMoreCoins(object sender, RoutedEventArgs e)
    {
        int sum = 0;
        //Hides InputBox and takes input text from user.
        InputBox.Visibility = System.Windows.Visibility.Collapsed;

        // Ensuring that input from user is a integer number
        String input = InputTextBox.Text;
        int result = 0;
        if (int.TryParse(input, out result))
        {
            //Adding number of coins to CoinListBox
            CoinListBox.Items.Add(result);
        }
        else
        {
            MessageBox.Show("Please enter a number of coins");
        }
        sum = CoinListBox.Items.Cast<object>().Sum(x => Convert.ToInt32(x));    
        if(sum > 30)
        {
            //Removing last coin in case number of coins exceeds 30
            CoinListBox.Items.RemoveAt(CoinListBox.Items.Count - 1);
            MessageBoxResult answer = MessageBox.Show("You cannot enter more than 30 coins. Do you want to end?", "Message", MessageBoxButton.YesNo, MessageBoxImage.Question);
            if (answer == MessageBoxResult.Yes)
            {
                Application.Current.Shutdown();
            }
        }

        // Resets InputBox.
        InputTextBox.Text = String.Empty;
    }

Answer 1

您的主要问题是在方法中声明sum。

只需使用：

     int sum = 0;
    private void ClickToAddMoreCoins(object sender, RoutedEventArgs e)
    {
        if (sum+(int) (InputTextBox.Text) > 30)
        {
            //Removing last coin in case number of coins exceeds 30
            CoinListBox.Items.RemoveAt(CoinListBox.Items.Count - 1);
            MessageBoxResult answer = MessageBox.Show("You cannot enter more than 30 coins. Do you want to end?", "Message", MessageBoxButton.YesNo, MessageBoxImage.Question);
            if (answer == MessageBoxResult.Yes)
            {
                Application.Current.Shutdown();
            }
        }     
        //Hides InputBox and takes input text from user.
        InputBox.Visibility = System.Windows.Visibility.Collapsed;

        // Ensuring that input from user is a integer number

        string number = InputTextBox.Text;
        int num;
        if(int.TryParse(number,out num))
        {
            sum += num;
          try { CoinListBox.Items.RemoveAt(0); 
              } catch
       {}
    CoinListBox.Items.Add(sum);
        }

        InputTextBox.Text = string.Empty;

    }

古德勒克。

Answer 2

Slashy的答案不完整，因为它允许添加负数。
如果您将InputTextBox的可见性设置为Collapsed，那么您将如何获得用户输入？什么是使用InputTextBox的意义？

如果您只想显示sum，则可以通过将其可见性设置为Collapsed来隐藏ListBox。所以，现在你的代码看起来像：

...
CoinListBox.Visibility = System.Windows.Visibility.Collapsed;
...
sum = CoinListBox.Items.Cast<object>().Sum(x => Convert.ToInt32(x));
            if (sum > 30)
            {
                sum -= result; // removing excess coin

                //Removing last coin in case number of coins exceeds 30
                CoinListBox.Items.RemoveAt(CoinListBox.Items.Count - 1);
                MessageBoxResult answer = MessageBox.Show("You cannot enter more than 30 coins. Do you want to end?", "Message", MessageBoxButton.YesNo, MessageBoxImage.Question);
                if (answer == MessageBoxResult.Yes)
                {
                    Application.Current.Shutdown();
                }
            }

您应该检查负数的更好的代码版本如下：

    List<int> coinList = new List<int>();
    private void ClickToAddMoreCoins2(object sender, RoutedEventArgs e)
    {
        int sum = 0;

//Hides InputBox and takes input text from user.
//InputTextBox.Visibility = System.Windows.Visibility.Collapsed;

// Ensuring that input from user is a integer number
String input = InputTextBox.Text;
int result = 0;
if (int.TryParse(input, out result) && result > 0)
{
    //Adding number of coins to CoinListBox
    coinList.Add(result);
}
else
{
    MessageBox.Show("Please enter a valid number of coins");
}
sum = coinList.Sum();
if (sum > 30)
{
    sum -= result;
    //Removing last coin in case number of coins exceeds 30
    coinList.RemoveAt(coinList.Count - 1);
    MessageBoxResult answer = MessageBox.Show("You cannot enter more than 30 coins. Do you want to end?", "Message", MessageBoxButton.YesNo, MessageBoxImage.Question);
    if (answer == MessageBoxResult.Yes)
    {
        Application.Current.Shutdown();
    }
}

tbSum.Text = "Sum = " + sum.ToString();

// Resets InputBox.
InputTextBox.Text = String.Empty;

InputTextBox.Focus();
    }

如何在WPF中绑定用户的输入？

2 个答案: