form1.cs

清华大学出版社出版的 移动应用开发宝典 张大威（2008）的附书源代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace FunctionPointer
{
    public partial class Form1 : Form
    {
        System.Text.StringBuilder sb = new StringBuilder(260);

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            NativeMethods.EnumWindows(new EnumWindowsDelegate(EnumWindowsProc), 0);
        }

        private bool EnumWindowsProc(IntPtr hwnd, int lParam)
        {
            //Add to list on UI thread.
            int chars = NativeMethods.GetWindowText(hwnd, sb, sb.Capacity);

            this.Invoke(new AddToListDelegate(AddToList), new object[] { hwnd, sb.ToString() });
            return true;
        }

        internal delegate void AddToListDelegate(IntPtr hwnd, string text);

        private void AddToList(IntPtr hwnd, string text)
        {
            listBox1.Items.Add(string.Format("[{0}] - {1}", hwnd.ToInt32().ToString("X"), text));
        }

        [return: MarshalAs(UnmanagedType.Bool)]
        private delegate bool EnumWindowsDelegate(IntPtr hwnd, int lParam);

        private static class NativeMethods
        {
            [DllImport("coredll")]
            [return: MarshalAs(UnmanagedType.Bool)]
            internal static extern bool EnumWindows(EnumWindowsDelegate lpEnumFunc, int lParam);

            [DllImport("coredll")]
            internal static extern int GetWindowText(IntPtr hWnd, System.Text.StringBuilder lpString, int nMaxCount);
        }
    }
}