c# winform 应用编程代码总结 12

43、修改系统的右键菜单

            if(args.Length>0)
            {
                Console.Write(args[0]);
                Console.Read();
            }
            else
            {
                Process p=Process.GetCurrentProcess();
                

                AssemblyName an=new AssemblyName();
                RegistryKey RegKey;
                RegKey=Registry.ClassesRoot;
                RegKey=RegKey.CreateSubKey("*\\shell\\MyApp");
                RegKey.SetValue("","What is this?");
                RegKey=Registry.ClassesRoot;
                RegKey=RegKey.CreateSubKey("*\\shell\\MyApp\\command");
                RegKey.SetValue("",p.MainWindowTitle+" %1");
                RegKey.Close();
            }

‍

44、屏蔽消息

        private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            MessageBox.Show("haha");
        }

        public bool PreFilterMessage(ref System.Windows.Forms.Message m)
        {
            if (m.Msg >= 513 && m.Msg <= 515) 
            {
                Console.WriteLine("Processing the messages : " + m.Msg);
                return true;
            }
            return false;
        }

        private void Form1_Load(object sender, System.EventArgs e)
        {
            Application.AddMessageFilter(this);
        }

        private void Form1_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            Application.RemoveMessageFilter(this);
        }

45、使程序只能够运行一个

        [StructLayout( LayoutKind.Sequential)]
        public class SECURITY_ATTRIBUTES 
        {
            public int nLength; 
            public int lpSecurityDescriptor; 
            public int bInheritHandle; 
        }

        [System.Runtime.InteropServices.DllImport("kernel32")]
        private static extern int GetLastError();
        [System.Runtime.InteropServices.DllImport("kernel32")]
        private static extern IntPtr CreateMutex(SECURITY_ATTRIBUTES lpMutexAttributes,bool bInitialOwner,string lpName);
        [System.Runtime.InteropServices.DllImport("kernel32")]
        private static extern int ReleaseMutex(IntPtr hMutex);
        const int ERROR_ALREADY_EXISTS = 0183;

        [STAThread]
        static void Main() 
        {
            IntPtr hMutex;
            hMutex=CreateMutex(null,false,"test");
            if (GetLastError()!=ERROR_ALREADY_EXISTS)
            {
                Application.Run(new Form1());
            }
            else
            {
                MessageBox.Show("本程序只允许同时运行一个");
                ReleaseMutex(hMutex);
            }
        }

46、设置系统时间

        [DllImport( "Kernel32.dll" )]
        public static extern void GetLocalTime(SystemTime st );
        [DllImport( "Kernel32.dll" )]
        public static extern void SetLocalTime(SystemTime st );

        [StructLayout( LayoutKind.Sequential)]
        public class SystemTime 
        {
            public ushort wYear; 
            public ushort wMonth; 
            public ushort wDayOfWeek; 
            public ushort wDay; 
            public ushort wHour; 
            public ushort wMinute; 
            public ushort wSecond; 
            public ushort wMilliseconds; 
        }

        private void timer1_Tick(object sender, System.EventArgs e)
        {
            SystemTime st = new SystemTime();
            GetLocalTime(st);
            this.Text="The Date and Time is: " ;
            this.Text=this.Text+st.wHour.ToString()+":";
            this.Text=this.Text+st.wMinute.ToString()+":";
            this.Text=this.Text+st.wSecond.ToString()+".";
            this.Text=this.Text+st.wMilliseconds.ToString();
        }

        private void Form1_Load(object sender, System.EventArgs e)
        {
            this.timer1.Interval=100;
            this.timer1.Enabled=true;
            this.dateTimePicker1.Value=DateTime.Now;
        }

        private void button1_Click(object sender, System.EventArgs e)
        {
            SystemTime st = new SystemTime();
            st.wYear=(ushort)this.dateTimePicker1.Value.Year;
            st.wMonth=(ushort)this.dateTimePicker1.Value.Month;
            st.wDay=(ushort)this.dateTimePicker1.Value.Day;
            st.wHour=(ushort)this.dateTimePicker1.Value.Hour;
            st.wMinute=(ushort)this.dateTimePicker1.Value.Minute;
            st.wSecond=(ushort)this.dateTimePicker1.Value.Second;
            SetLocalTime(st);
        }

作者：syxChina
本系列文章是作者学习《Visual C#.NET 应用编程150例》（源码）心得笔记，欢迎转载，请注明原文地址，如有疑问，可以通过 278250658@qq.com 联系作者本人。