C# - 不能在同一源中的 WPF 项目中使用 .NET 框架项目中的类

Question

UPDATE: I tried working out by making every class in Code public, but it doesn't seem to accept my class hierarchy.

This is my first post so please bear with me. Besides that, i'm a pretty big noob, so do excuse me if something dumb comes along

I'm currently doing a school project and I have a fully fleshed out .NET Framework project in Visual Studio. Now I have to visualize it with a WPF app. So I made a new WPF project in the same source.

Let's respectively call them Code and Visualization .

I've given Visualization a project reference to Code and put using Code; at the top of the XAML.cs I made a button in Visualization and I want it's OnClick event to use

Code.Start();

What somehow seems to sort of work is making every class in Code public , but I don't remember that being a good practice, but do correct me if i'm wrong!

I've put multiple hours into finding a solution with none to be really found before. Seeing as nobody seems to have posted this question before I must be missing something really simple.

Cheers!

namespace Code
{
    class Program
    {
        public void Start() 
        {
            /// Do something
        }
    }
}

---

using Code;

namespace Visualization
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Start_Click(object sender, RoutedEventArgs e)
        {
            // Use the Start() function from Code
        }
    }
}

Answer 1

To use classes and their functions and properties from another project, you have to declare them as public .

namespace Code
{
    public class Program
    {
        public void Start() 
        {
            // Do something
        }
    }
}

Then go to the other project, right click > Add > Reference > select your project containing the code above (assuming you're using Visual Studio IDE). After, you can access the public functions and properties:

using Code;

namespace Visualization
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Start_Click(object sender, RoutedEventArgs e)
        {
            Program p = new Program();
            p.Start();
        }
    }
}

If you are worried about security, then ensure that public functions and properties you deem are safe to expose to other projects. For example, what we just did to use the Start function, any other project or some 3rd party program could do also. The only difference is that a reference would be made to the project's.dll produced instead of the project itself.

A basic rule of thumb (at least for me) is that if there are anything I don't want to expose, then don't make them public and have a public function that can be called to perform different actions. This way I can limit what actions and information can be performed or accessed:

//within some project
namespace Code
{
    public class Program
    {
        // can't be access from another project directly
        private string _privateText { get;set; }

        // can be accessed directly
        public string PublicText { get;set; }

        public void Start() 
        {
            // Do something
        }

        public string getPrivateText() 
        {
            // here you can limit what actions are done and what information to return
            return _privateText;
        }
    }
}

You can then do the following:

// within another project
using Code;

namespace Visualization
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Start_Click(object sender, RoutedEventArgs e)
        {
            Program p = new Program();
            string s1 = p.getPrivateText();
            string s2 = p.PublicText;
            p.Start();
        }
    }
}

Hope this helps!