封装dll

首先创建 .Net平台 类库

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _09.Encapsulation_dll
{
    public class Program
    {
        /// <summary>
        /// 求两个double类型的数值的和
        /// </summary>
        /// <param name="x">加数</param>
        /// <param name="y">加数</param>
        /// <returns>和</returns>
        public double mathAdd(double x,double y)
        {
            return x + y;
        }
      
    }
}

调用dll

先创建一个Winform控件，引用我们上面创建的类库

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using _09;
using _09.Encapsulation_dll;

namespace _09.Invoke_dll
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btn_mathAdd_Click(object sender, EventArgs e)
        {
            Class1 mathadd = new Class1();
            double sum=mathadd.mathAdd(4, 11);
            MessageBox.Show(sum.ToString(), "Surprise !");
        }
    }
}