Mono for android，Xamarin点击事件的多种写法

（一）原本java的写法（相信很多是学过java的）：

需要实现接口View.IOnClickListener，最好也继承类：Activity，因为View.IOnClickListener接口又继承了IJavaObject, IDisposable接口，所以还学要实现这两个接口里面的成员，而Activity已经实现可了这两个接口的成员，就不需要我们再写了，毕竟我们大部分只想重写View.IOnClickListener里面的OnClick函数。（如果自定义的类只是实现了View.IOnClickListener接口，不继承Activity，就需要实现另外2个接口的其他成员，在vs中选中接口，使用快捷键Alt+Shift+F10，可快速实现接口）

代码如下：

using System;
using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;

namespace App2
{
    [Activity(Label = "App2", MainLauncher = true, Icon = "@drawable/icon")]


    public class MainActivity : Activity, View.IOnClickListener
    {
        Button button;
        public void OnClick(View v)
        {
           button.Text = string.Format("{0} clicks!", v.Id);
        }
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource,
            // and attach an event to it
             button = FindViewById<Button>(Resource.Id.MyButton);
             button.SetOnClickListener(this);
          
         }
        }
}

当然也可以自己定义一个类，实现接口，重写OnClick函数，然后button.SetOnClickListener(你自定义类的实例);

（二）接下来介绍C#的4种写法（其实大同小异）

1.第一种（创建模板就有的）：

Button button = FindViewById<Button>(Resource.Id.MyButton);
 button.Click += delegate { button.Text = string.Format ("{0} clicks!", count++);};

2.第二种

namespace App2
{
    [Activity(Label = "App2", MainLauncher = true, Icon = "@drawable/icon")]


    public class MainActivity : Activity, View.IOnClickListener
    {
        int count = 1;
        Button button;
       
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource,
            // and attach an event to it
             button = FindViewById<Button>(Resource.Id.MyButton);
             button.Click +=button_Click;
          
         }

        private void button_Click(object sender, EventArgs e)
        {
            button.Text = string.Format("{0} clicks!", count++);
        }

        
        }
}

3.第三种

public class MainActivity : Activity, View.IOnClickListener
    {
        int count = 1;
        Button button;
       
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource,
            // and attach an event to it
             button = FindViewById<Button>(Resource.Id.MyButton);
             button.Click += new EventHandler(button_Click);
          
         }

        private void button_Click(object sender, EventArgs e)
        {
            button.Text = string.Format("{0} clicks!", count++);
        }

        
        }

4.第四种

namespace App2
{
    [Activity(Label = "App2", MainLauncher = true, Icon = "@drawable/icon")]


    public class MainActivity : Activity, View.IOnClickListener
    {
        int count = 1;
        Button button;
       
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            // Get our button from the layout resource,
            // and attach an event to it
             button = FindViewById<Button>(Resource.Id.MyButton);
             button.Click += (sender, e) =>{ button.Text = string.Format ("{0} clicks!", count++);};
     
         }
        }
}