C#接口编程实例向你讲述了事件与接口的联合应用很多初学C#的朋友对于事件与接口感到迷惑不解,不明白它们之间的关系,下面我就用实例来简单的分析讲解一下。
C#接口编程实例问题的解决之前我们来看看事件的创建过程,用event修饰符来代表一个事件,我们要创建一个C#事件必须按以下顺序来扫行:
C#接口编程实例1,创建或标识一个代表。
比如下例中的
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public delegate void dele(); //声明代表,delegate 关键字通知编译器dele是一个委托类型
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C#接口编程实例2,创建一个包含事件处理代表,调用事件处理代表的方法的类
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public class EventClass1 : IEvents //IEvents,是下面我们要讲一接口 { public event dele event1;//定义事件成员event1 public void FireEvent() //当事件发生时 { event1(); //调用事件处理 } }
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EventClass1继承接口IEvents,以下后面的EventClass2~4,都是一样。
C#接口编程实例3,定义一个或多个把方法连接到事件的类
C#接口编程实例4,使用事件
4.1 定义事件响应方法,如下例中的
IEvents id1 = new EventClass1();
4.2 使用所定义的构造函数创建一个包含事件的对象,如下例中的
id1.event1 += new dele(EventFired1);
4.3 触发事件,如下例中的
id1.FireEvent();
下面我们来看看接口,我们必须用interface来声明一个接口。接口声明可以声明零个或多个成员。接口的成员必须是方法、属性、事件或索引器。接口不能包含常数、字段、运算符、实例构造函数、析构函数或类型,也不能包含任何种类的静态成员。
所有接口成员都隐式地具有 public 访问权限。接口成员声明包含任何修饰符属于编译时错误。具体地说,接口成员包含下列任何修饰符属于编译时错误:abstract、public、protected、internal、private、virtual、override 或 static。更多的信息请看msdn help://MS.VSCC/MS.MSDNVS.2052/csspec/html/vclrfcsharpspec_13_1.htm
在下面的例子中,我们声明IEvents接口,一个方法FireEvent和一个事件event1
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public interface IEvents { event dele event1; //定义事件 void FireEvent();//定义接口 }
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在后面的EventClass1~4类是继承了接口IEvent,因此在这几个类中必须实现上述一个方法和一个事件。下面的实例可以帮助大家更好的理解。
这是一个简单的windows Forms,包含一个textbox,几个labels和一个button,在程序启动时焦点在textbox,捕捉键盘按下事件,除方向键外,我能过接口来触事方向键按下事件。#p#
下面的代码是一个网上常见的C#接口编程实例,大家可以拷贝下来,保存为.cs文件,用CSC编译就行
C#接口编程实例代码如下:
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using System; using System.Drawing; using System.Collections; using System.ComponentModel; using System.Windows.Forms; using System.Data; namespace Events_Interfaces { public delegate void dele(); //声明代表 delegate 关键字通知编译器 dele 是一个委托类型 public interface IEvents //定义接口IEvents,包含方法FireEvent事件event1 { event dele event1; void FireEvent(); } public class Form1 : System.Windows.Forms.Form { private System.Windows.Forms.Label label1; private System.Windows.Forms.TextBox textBox1; private System.Windows.Forms.Label label2; private System.Windows.Forms.Button button1; private System.Windows.Forms.Label label3; private System.ComponentModel.Container components =null; public Form1() { InitializeComponent(); } protected override void Dispose( bool disposing ) { if( disposing ) { if (components != null) { components.Dispose(); } } base.Dispose( disposing ); } #region Windows Form Designer generated code private void InitializeComponent() { this.textBox1 = new System.Windows.Forms.TextBox(); this.label1 = new System.Windows.Forms.Label(); this.button1 = new System.Windows.Forms.Button(); this.label2 = new System.Windows.Forms.Label(); this.label3 = new System.Windows.Forms.Label(); this.SuspendLayout(); this.textBox1.Location = new System.Drawing.Point(8, 80); this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(56,23); this.textBox1.TabIndex = 1; this.textBox1.Text = ""; this.textBox1.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Key_Press); this.label1.Location = new System.Drawing.Point(16, 16); this.label1.Name = "label1"; this.label1.Size = new System.Drawing.Size(256,64); this.label1.TabIndex = 0; this.label1.Text = "Whenever you use the arrow keys inside the text box, Corresponding events will be" +" fired to display the label appropriately. Have a try!!"; this.button1.Location = new System.Drawing.Point(240, 112); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(48,23); this.button1.TabIndex = 3; this.button1.Text = "Exit"; this.button1.Click += new System.EventHandler(this.button1_Click); // // label2 // this.label2.Location = new System.Drawing.Point(88, 80); this.label2.Name = "label2"; this.label2.Size = new System.Drawing.Size(184,23); this.label2.TabIndex = 2; this.label2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; // // label3 //C#接口编程实例 this.label3.Location = new System.Drawing.Point(8, 104); this.label3.Name = "label3"; this.label3.Size = new System.Drawing.Size(64,23); this.label3.TabIndex = 4; this.label3.TextAlign = System.Drawing.ContentAlignment.MiddleCenter; // // Form1 //C#接口编程实例 this.AutoScaleBaseSize = new System.Drawing.Size(6, 16); this.ClientSize = new System.Drawing.Size(292,141); this.Controls.AddRange( new System.Windows.Forms.Control[] { this.label3,this.button1,this.label2, this.textBox1,this.label1}); this.Font= new System.Drawing.Font( "Comic SansMS",8.25F,System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point,((System.Byte)(0))); this.Name = "Form1"; this.Text = "Events"; this.ResumeLayout(false); } #endregion static void Main() { Application.Run(new Form1()); } private void Key_Press(object sender, System.Windows.Forms.KeyEventArgs e) { textBox1.Text = ""; label2.Text = ""; string keyId = e.KeyCode.ToString(); switch (keyId)//判断是否按下方向键 { case "Right": label3.Text = ""; IEvents id1 = new EventClass1(); //实例化一个接口 id1.event1 += new dele(EventFired1); //定义EventClass1中的事件响应方法 id1.FireEvent(); //调用EventClass1中的FireEvent方法, //触发event1 事件,事件调用EventFired1方法 break; case "Left": label3.Text = ""; IEvents id2 = new EventClass2(); id2.event1 += new dele(EventFired2); id2.FireEvent(); break; case "Down": label3.Text = ""; IEvents id3 = new EventClass3(); id3.event1 += new dele(EventFired3); id3.FireEvent(); break; case "Up": label3.Text = ""; IEvents id4 = new EventClass4(); id4.event1 += new dele(EventFired4); id4.FireEvent(); break; default: label3.Text = keyId; break; } } //EventFired1方法 public void EventFired1() { label2.Text = ""; label2.Text = "You pressed RIGHT arrow key"; } public void EventFired2() { label2.Text = ""; label2.Text = "You pressed LEFT arrow key"; } public void EventFired3() { label2.Text = ""; label2.Text = "You pressed DOWN arrow key"; } public void EventFired4() { label2.Text = ""; label2.Text = "You pressed UP arrow key"; } //C#接口编程实例 private void button1_Click(object sender, System.EventArgs e) { Application.Exit(); } } public class EventClass1 : IEvents { public event dele event1; public void FireEvent() { event1(); } } public class EventClass2 : IEvents { public event dele event1; public void FireEvent() { event1(); } } public class EventClass3 : IEvents { public event dele event1; public void FireEvent() { event1(); } } public class EventClass4 : IEvents//EventClass1继承接口IEvents { public event dele event1;//定义事件成员event1 //当事件发生时 public void FireEvent() { event1();//C#接口编程实例之调用事件处理 } } }
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C#接口编程实例的基本内容就向你介绍到这里,希望对你了解和学习C#接口编程有所帮助。
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