外部方法使用C#简单例子

1、增加引用using System.Runtime.InteropServices;

2、声明和实现的连接[DllImport("kernel32", SetLastError = true)]

3、声明外部方法public static extern int GetCurrentDirectory(int a, StringBuilder b);

4、对外部方法操作 GetCurrentDirectory(300, pathstring);

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Runtime.InteropServices;//引用外部

namespace extern

{

    public partial class DllImportForm : Form

    {

        public DllImportForm()

        {

            InitializeComponent();

        }

        [DllImport("kernel32", SetLastError = true)]//声明和实现的连接

        public static extern int GetCurrentDirectory(int a, StringBuilder b);//外部方法

        private void btnDisplay_Click(object sender, EventArgs e)

        {

            StringBuilder pathstring=new StringBuilder ();//返回路径

            GetCurrentDirectory(300, pathstring);

           this.listBox1.Items.Add (pathstring );

        }

    }

}

extern外部方法使用C#简单例子