如何在C＃中多次为DatePicker设置正确的验证？

Question

我的出生日期有验证问题。 我通过不填写所有字段来调试它，然后我注意到由于this.dateOfBirthPicker = dtN（以编程方式发生），“ dateOfBirthPicker_ValueChanged”仍将被调用。 当我确实使用'dateofBirthPicker'时，'dateOfBirthTBL'文本块仍然是红色，粗体且包含星号。 因为，在if语句中，我想在用户单击，打开和修改datePicker之后将其恢复为默认值，但是我不确定如何逻辑地执行此操作。

另外，如何限制datePicker的最大日期，因为每次尝试使用这些date方法之一时，都会给我丢失的指令或程序集引用。 我不知道可以使用哪个类或包。

dateOfBirthPicker.DisplayDateEnd = DateTime.Now;

C＃代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Navigation;
using System.Windows.Media; // added to support SolidColorBrush, FontWeights, etc...
using Microsoft.Phone.Controls;
using Microsoft.Phone.Shell;
using Data_Query.Resources;
using System.Windows.Input;

namespace Data_Query
{
public partial class MainPage : PhoneApplicationPage
{
    // Constructor
    public MainPage()
    {
        InitializeComponent();
    }

    DateTime dtN; // var to set current time
    bool clicked = false; // returns true if the 'fingerprintB' Button or DateTimePicker was clicked at least once; otherwise false.

    // user's date of birth by using a date picker
    private void dateOfBirthPicker_ValueChanged(object sender, DateTimeValueChangedEventArgs e)
    {
        if(clicked) return;
        //MessageBox.Show("You are in the DateTimePicker.ValueChanged event.");
    }

    // validates first, beforing sending the user's information into a database query 
    private void submitButton(object sender, RoutedEventArgs e)
    {
        //------------------------------------FIRST NAME-------------------------------//
        if(string.IsNullOrWhiteSpace(firstNameTB.Text) || firstNameTB.Text == "")
        {
            firstNameTBL.Text = "First Name: *";
            firstNameTBL.Foreground = new SolidColorBrush(Colors.Red);
            firstNameTBL.FontWeight = FontWeights.Bold;
        }
        else if(!(string.IsNullOrWhiteSpace(firstNameTB.Text) || firstNameTB.Text == ""))
        {
            // set back to default layout
            this.firstNameTBL.ClearValue(TextBlock.ForegroundProperty);
            this.firstNameTBL.ClearValue(TextBlock.FontWeightProperty);
            this.firstNameTBL.Text = "First Name:";
        }
        //------------------------------------LAST NAME-------------------------------//
        if(string.IsNullOrWhiteSpace(lastNameTB.Text) || lastNameTB.Text == "")
        {
            lastNameTBL.Text = "Last Name: *";
            lastNameTBL.Foreground = new SolidColorBrush(Colors.Red);
            lastNameTBL.FontWeight = FontWeights.Bold;
        }
        else if(!(string.IsNullOrWhiteSpace(lastNameTB.Text) || lastNameTB.Text == ""))
        {
            // set back to default layout
            this.lastNameTBL.ClearValue(TextBlock.ForegroundProperty);
            this.lastNameTBL.ClearValue(TextBlock.FontWeightProperty);
            this.lastNameTBL.Text = "Last Name:";
        }
        //------------------------------------EMAIL ADDRESS-------------------------------//
        if(string.IsNullOrWhiteSpace(emailAddressTB.Text) || emailAddressTB.Text == "")
        {
            emailAddressTBL.Text = "Email Address: *";
            emailAddressTBL.Foreground = new SolidColorBrush(Colors.Red);
            emailAddressTBL.FontWeight = FontWeights.Bold;
        }
        else if (!(string.IsNullOrWhiteSpace(emailAddressTB.Text) || emailAddressTB.Text == ""))
        {
            // set back to default layout
            this.emailAddressTBL.ClearValue(TextBlock.ForegroundProperty);
            this.emailAddressTBL.ClearValue(TextBlock.FontWeightProperty);
            this.emailAddressTBL.Text = "Email Address:";
        }
        //------------------------------------DATE OF BIRTH-------------------------------//
        //if()
        //dateOfBirthPicker.DisplayDateEnd = DateTime.Now;

        clicked = true; // prevent the validation code from running
        dtN = DateTime.Now; // initialize DateTime.Now to be use in value comparsion with DateTimePicker
        this.dateOfBirthPicker.Value = dtN; // set current time for DateTimePicker to match dtN
        clicked = false; // allow it to run again
        if(dateOfBirthPicker.Value == dtN) // true when user hasn't changed or set the DateTimePicker
        {
            dateOfBirthTBL.Text = "Date of Birth: *";
            dateOfBirthTBL.Foreground = new SolidColorBrush(Colors.Red);
            dateOfBirthTBL.FontWeight = FontWeights.Bold;
        }
        else if(clicked)
        {
            // set back to default layout
            this.dateOfBirthTBL.ClearValue(TextBlock.ForegroundProperty);
            this.dateOfBirthTBL.ClearValue(TextBlock.FontWeightProperty);
            this.dateOfBirthTBL.Text = "Date of Birth:";
        }
        //------------------------------------GENDER-------------------------------//
        if(maleRB.IsChecked == false && femaleRB.IsChecked == false)
        {
            genderTBL.Text = "Gender: *";
            genderTBL.Foreground = new SolidColorBrush(Colors.Red);
            genderTBL.FontWeight = FontWeights.Bold;
        }
        else if(!(maleRB.IsChecked == false && femaleRB.IsChecked == false))
        {
            // set back to default layout
            this.genderTBL.ClearValue(TextBlock.ForegroundProperty);
            this.genderTBL.ClearValue(TextBlock.FontWeightProperty);
            this.genderTBL.Text = "Gender:";
        }
        //------------------------------------FINGERPRINT-------------------------------//
        if(!clicked)
        {
            MessageBox.Show("Fingerprint Scan was not completed! \nPlease scan your fingerprint until the progress bar is full!", "Notice!", MessageBoxButton.OK);
            fingerprintTBL.Text = "Fingerprint: *";
            fingerprintTBL.Foreground = new SolidColorBrush(Colors.Red);
            fingerprintTBL.FontWeight = FontWeights.Bold;
        }
        else if(clicked)
        {
            // set back to default layout
            this.fingerprintTBL.ClearValue(TextBlock.ForegroundProperty);
            this.fingerprintTBL.ClearValue(TextBlock.FontWeightProperty);
            this.fingerprintTBL.Text = "Fingerprint:";
        }

    }

    // clear all user's information inputs
    private void resetButton(object sender, RoutedEventArgs e)
    {
        firstNameTB.Text = string.Empty;
        lastNameTB.Text = string.Empty;
        emailAddressTB.Text = string.Empty;
        dateOfBirthPicker.Value = DateTime.Now;
        maleRB.IsChecked = false;
        femaleRB.IsChecked = false;
        clicked = false;
    }

    // supply a method to allow you to use the SIP Enter key to dismiss the SIP
    private void TextBox_KeyUp(object sender, KeyEventArgs e)
    {
        if(e.Key == Key.Enter)
        {
            this.Focus();
        }
    }
}

}

Answer 1

您可以使用布尔标志。 例如：

var manualDateChange = false;

void datepicker_valuechange(object sender, DateTimeValueChangedEventArgs e)
{
    if(manualDateChange) return;

    //Do your validation here
}

void someFunctionThatChangesTheDate()
{
    manualDateChange = true; //prevent the validation code from running
    datepicker.Value = DateTime.Now;
    manualDateChange = false; //allow it to run again
}

注意：如果您担心更改manualDateChange将使用户无需验证即可对其进行更改，请记住所有事件处理代码都在主线程上执行，并且在代码运行时，用户无法与任何用户界面元素进行交互。 因此，只要您设置标志，设置值并重置标志，它就安全了。

编辑：如果要设置最大日期， DatePicker.MaxYear设置DatePicker.MaxYear因为这是Windows Phone 8中唯一的真实选项DatePicker.MaxYear : //msdn.microsoft.com/zh-CN/library/窗口/应用/ windows.ui.xaml.controls.datepicker.maxyear