从文本框使用 textchange 事件到 add/subtract

Question

我有 6 个文本框 2 用于需要支付的每种类型的账单：

如果我在两者之一中输入一个数字，它会更新另一个数字：

面板中的文本框将始终添加相同的总和，如果您更改值，它会自动更改其相邻文本框的值，但 RENT 文本框不同。

我正在努力使 RENT 文本框在 3 对其他文本框之间取（差值 / 2）。因此，如果 patti 比 mike 多支付 100 美元的水费，则 mike 必须支付这 100 美元的租金，这也从 patti 的租金中减去 100 美元。

我目前的 code 结果是：

如您所见，它没有正确更新租金文本框。我已经尝试这样做了半天多一点，但我看不出我做错了什么或者我的数学可能出了什么问题。这是我的文本框的文本更改事件的所有代码

    private void txtMikeWater_TextChanged(object sender, EventArgs e)
    {
        double num;
        bool parse = Double.TryParse(txtMikeWater.Text, out num);
        if (txtMikeWater.Focused == true)
            if (parse && num >= 0 && num <= expenses[2])
                txtPattiWater.Text = (expenses[2] - num).ToString();
            else
                textBoxValidator(txtMikeWater, expenses[2], 0);

        double difference = Math.Abs(num - Convert.ToDouble(txtPattiWater.Text)) / 2;
        if (num > Convert.ToDouble(txtPattiWater.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
    }

    private void txtMikeElectric_TextChanged(object sender, EventArgs e)
    {
        double num;
        bool parse = Double.TryParse(txtMikeElectric.Text, out num);
        if (txtMikeElectric.Focused)
            if (parse && num >= 0 && num <= expenses[3])
                txtPattiElectric.Text = (expenses[3] - num).ToString();
        double difference = Math.Abs(num - Convert.ToDouble(txtPattiElectric.Text)) / 2;


        if (num > Convert.ToDouble(txtPattiElectric.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else if (num < Convert.ToDouble(txtPattiElectric.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
        }
    }

    private void txtMikeInternet_TextChanged(object sender, EventArgs e)
    {


        double num;
        bool parse = Double.TryParse(txtMikeInternet.Text, out num);
        if (txtMikeInternet.Focused)
            if (parse && num >= 0 && num <= expenses[1])
                txtPattiInternet.Text = (expenses[1] - num).ToString();
        double difference = Math.Abs(num - Convert.ToDouble(txtPattiInternet.Text)) / 2;


        if (num > Convert.ToDouble(txtPattiInternet.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else if (num < Convert.ToDouble(txtPattiInternet.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
        }
    }

    private void txtPattiWater_TextChanged(object sender, EventArgs e)
    {

        double num;
        bool parse = Double.TryParse(txtPattiWater.Text, out num);
        if (txtPattiWater.Focused == true)
            if (parse && num >= 0 && num <= expenses[2])
                txtMikeWater.Text = (expenses[2] - num).ToString();
        double difference = Math.Abs(num - Convert.ToDouble(txtMikeWater.Text)) / 2;


        if (num < Convert.ToDouble(txtMikeWater.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else
        {
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
        }

    }

    private void txtPattiElectric_TextChanged(object sender, EventArgs e)
    {

        double num;
        bool parse = Double.TryParse(txtPattiElectric.Text, out num);
        if (txtPattiElectric.Focused)
            if (parse && num >= 0 && num <= expenses[3])
                txtMikeElectric.Text = (expenses[3] - num).ToString();
        double difference = Math.Abs(num - Convert.ToDouble(txtMikeElectric.Text)) / 2;
        if (num < Convert.ToDouble(txtMikeElectric.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else if (num > Convert.ToDouble(txtMikeElectric.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
        }
    }

    private void txtPattiInternet_TextChanged(object sender, EventArgs e)
    {
        double num;
        bool parse = Double.TryParse(txtPattiInternet.Text, out num);
        if (txtPattiInternet.Focused)

            if (parse && num >= 0 && num <= expenses[1])
                txtMikeInternet.Text = (expenses[1] - num).ToString();

        double difference = Math.Abs(num - Convert.ToDouble(txtMikeWater.Text)) / 2;
        if (num < Convert.ToDouble(txtMikeWater.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) + difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) - difference).ToString();
        }
        else if (num > Convert.ToDouble(txtMikeWater.Text))
        {
            txtPattiRent.Text = ((expenses[0] / 2) - difference).ToString();
            txtMikeRent.Text = ((expenses[0] / 2) + difference).ToString();
        }

    }

expenses 变量只存储文本框对应该具有的总和。

如果有人能帮忙，我将不胜感激。

编辑只是为了更清楚地了解费用变量。

expenses[0] = total rent 
expenses[1] = total internet 
expenses[2] = total water
expenses[3] = total electricity

Answer 1

看来您的租金重新计算仅根据单笔费用的差异而变化，而不是所有费用的总差异。

我建议您创建一个单一的 UpdateRent() 方法，将每个人支付的总费用相加，然后计算差额：

private void txtPattiElectric_TextChanged(object sender, EventArgs e)
{

    double num;
    bool parse = Double.TryParse(txtPattiElectric.Text, out num);
    if (txtPattiElectric.Focused)
        if (parse && num >= 0 && num <= expenses[3])
            txtMikeElectric.Text = (expenses[3] - num).ToString();

    UpdateRent();
}

您的租金计算可能如下所示：

private void UpdateRent()
{
    double pattiPaid = GetPattiWater() + GetPattiElectric() + GetPattiInternet();
    double mikePaid = GetMikeWater() + GetMikeElectric() + GetMikeInternet();

    double difference = pattiPaid - mikePaid;
    double baseRent = GetRequiredMonthlyRent() / 2;

    double pattiRent = baseRent - difference;
    double mikeRent = baseRent + difference;

    txtPattiRent.Text = pattiRent.ToString();
    txtMikeRent.Text = mikeRent.ToString();
}

我还建议您将大部分 parsing/handling 代码移至辅助方法（如上所示），以便更容易跟踪和调试一般逻辑。

编辑：另请注意，代码消除了检查谁支付更多的费用。这一切都在数学上解决了。例如，如果 Mike 支付更多，则 difference 为负数。那么这个负数是 "subtracted" 来自 Patti 的基本租金，有效地增加了它。如果您发现它使您的代码更易于理解、调试和维护，请随时重新引入 if 检查来完成相同的工作。

EDITx2：我原来的回答不是很清楚。 GetPattiWater() 和 GetRequiredMonthlyRent() 等方法应该只是 read/return 当前值：

private double GetPattiWater()
{
    double amount;
    Double.TryParse(txtPattiWater.Text, out amount);
    return amount;
}

private double GetRequiredMonthlyRent()
{
    return expenses[3];
}

您可能需要对文本字段中的 temporary/blank/invalid 不可解析的输入做一些特殊处理（上面只是 return 0），但将其视为零可能更简单暂时.

从文本框使用 textchange 事件到 add/subtract

using textchange event to add/subtract from a textbox

c#

math

textbox

winforms