c# - 从对话框窗口获取值

Question

我无法获取弹出对话框的文本框的值。我听从了其他 StackOverflow 问题的建议，即在 program.cs 中创建一个公共(public)变量:

public static string cashTendered { get; set; } 

然后我创建了这样的对话框:

Cash cashform = new Cash();
cashform.ShowDialog();

当用户按下对话框上的按钮时，这称为:

        if (isNumeric(textBox1.Text, System.Globalization.NumberStyles.Float))
        {
            Program.cashTendered = textBox1.Text;
            this.Close();
        }
        else
        {
            MessageBox.Show("Please enter a valid amount of cash tendered. E.g. '5.50'");
        }

然而 Program.cashTendered 保持为空。难道我做错了什么？谢谢!

Answer 1

对于初学者来说，名为 Cash 的表单应该使用面向对象的设计。它应该有一个名为 CashEntered 或类似 decimal 类型的公共(public)属性，而不是字符串。您可以这样调用表单:

using (var cashDialog = new CashDialog())
{
    // pass a reference to the Form or a control in the Form which "owns" this dialog for proper modal display.
    if (cashDialog.ShowDialog(this) == DialogResult.OK)
    {
        ProcessTender(cashDialog.CashEntered);
    }
    else
    {
        // user cancelled the process, you probably don't need to do anything here
    }
}

使用静态变量来保存临时对话的结果是一种不好的做法。这是对话的更好实现:

public class CashDialog : Form
{
    public decimal CashEntered { get; private set; }

    private void ok_btn_Clicked
    {
        decimal value;
        if (Decimal.TryParse(cashEntered_txt.Text, out value))
        {
            // add business logic here if you want to validate that the number is nonzero, positive, rounded to the nearest penny, etc.

            CashEntered = value;
            DialogResult = DialogResult.OK;
        }
        else
        {
            MessageBox.Show("Please enter a valid amount of cash tendered. E.g. '5.50'");
        }
    }
}