如何在不同的cs文件中使用字符串

Question

我正在尝试在这样的welcomePage.cs文件中使用string user = textbox1.Text;，string user = MainPage.textbox1.Text;我一直收到错误：

此处更新了照片：http://imgur.com/a/ZCfdm

using System;
using System.Diagnostics;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

namespace Gregoua_Technologies
{
public sealed partial class welcomePage : Page
{
    public MainPage mpInstance;

    public welcomePage(MainPage mp)
    {
        this.InitializeComponent();

        //Will put the MainPage that this was called from into a variable
        this.mpInstance = mp;
    }

    public void test_TextChanged(object sender, TextChangedEventArgs e)
    {
        //Get the instance of main page, and get the textbox1 text.
        string user = this.mpInstance.textbox1.Text;
        box.Text = "User: " + user;
    }

    public void priv_Clicked(object sender, PointerRoutedEventArgs e)
    {
        this.Frame.Navigate(typeof(TermsAndConditions), null);
    }

    public void function_Clicked(object sender, PointerRoutedEventArgs e)
    {
        this.Frame.Navigate(typeof(FunctionPage), null);
    }
    public void terms_Clicked(object sender, PointerRoutedEventArgs e)
    {
        this.Frame.Navigate(typeof(TermsAndConditions), null);
    }
   }
 }      

我的帖子主要是代码我猜这里你去staack溢出

Answer 1

静态变量和实例变量之间存在差异。 textbox1是一个实例变量（在MainPage类中），因此您需要使用创建的MainPage实例（通常在加载应用程序时）访问它。

您需要将上一页（MainPage）中的信息传递给welcomePage。

将welcomePage()更改为：

public string username;

public welcomePage()
{
    this.InitializeComponent();
}

protected override void OnNavigatedTo(NavigationEventArgs e)
{
    this.username = e.Parameter as string;
}

public void test_TextChanged(object sender, TextChangedEventArgs e)
{
    //string username = test.Text;
    box.Text = "User: " + this.username;
 }

请务必将您的用户名从您的MainPage类传递给welcomePage：

this.Frame.Navigate(typeof(welcomePage), this.textbox1.Text);

Answer 2

您需要创建MainPage的实例（并确保textbox1成员不是私有的），或者您需要将textbox1成员设置为静态。这是直接从另一个类访问textbox1.Text的两种方法。

实际上在您的情况下，您应该在MainPage类中创建welcomePage的实例，因为另一个选项可能会导致线程安全问题。

Answer 3

使用公共静态字段

public static string UserName { get; set; }

public void test_TextChanged(object sender, TextChangedEventArgs e)
{
    string user = MainPage.textbox1.Text;
    welcomePage.UserName = test.Text;
    box.Text = "User: " + welcomePage.UserName;
 }