The following instructions explain the custom triggering process for custom events:
Directly on the code, containing instructions (interface is two text box Textbox1,textbox2, and a Button1, interface Load event, button's Click event)
Form1 Class (caller side)
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; namespace test{public partial class Form1:form {public Form1 () {InitializeComponent (); }//customclass cc = new Customclass (1, "Lee");//test the property value does not change the situation customclass cc = new Customclass ();// Null constructor, side test property value change private void Form1_Load (object sender, EventArgs e) { cc. Changed + = new Customclass.changedeventhandler (cc_changed);//caller-side subscription event provides a specific event function for the Changed event cc_changed private void Button1_Click (object sender, EventArgs e) { cc. Cid = 1;cc. Cname = "Lee";//Assign a value to the Customclass attribute, which is the event that is raisedString str = cc. Cid.tostring () + CC. Cname; MessageBox.Show (str); }private voidcc_changed ()//Event Note: Event functions bound by custom events{TextBox1.Text = cc. Cid.tostring (); TextBox2.Text = cc. Cname; } }Customclass Class (event definition side)
public class Customclass {public delegate void Changedeventhandler ();//define Delegate public event Changedeventhan Dler changed;//define event private int _cid; private string _cname; Public Customclass () {}
public customclass (int cCid, string ccname) { & nbsp THIS._CID = ccid; This._cname = ccname; } protected virtual void OnChanged () { &NBS P if (changed!=null) { &NBSP ; Changed (); } } public int cid { get { return _cid; &NB Sp } set { &NBSP ; if (_cid!=value)//Here is the process of text change { & nbsp _CID = value; OnChanged ();//Start Event//Note: In disguise in changing the value of the process, called the above bound event function "cc_changed ()", to the custom event trigger (cc_changed () Illusion execution ) //need to understand: in the current classCustomclass, you cannot directly know the event function to execute //or so: in the class that defines the custom event, simply define (1) the event itself and (2) the event invocation that may be triggered in the class (In this class, the onchanged () changed () ), which event function is called, is provided by the caller-side }}} public string Cname {get {return _cname; } set {if (_cname! = value) {_cname = VA Lue OnChanged (); } } } }}
The following is an example of a very classic property value change on the web that raises a custom event, as follows;public class MyClass {public event eventhandler<propertychagedeventargs> mypropertychanging; public event eventhandler<propertychagedeventargs> Mypropertychanged;
private int _myproperty; public int myproperty { get {return _myproperty;} set { if (value! = _myproperty) { &NBS P Propertychagedeventargs e = new Propertychagedeventargs ("MyProperty", _my property, value),//Initialize if (this. Mypropertychanging! = null) { &NB Sp this. Mypropertychanging (this, e); if (E.canc EL) return; &nbsP } &N Bsp _myproperty = (int) e.newvalue; if (this. Mypropertychanged! = null) { &NBS P this. Mypropertychanged (this, e); } &NB Sp } } } } //<summary> //General class //</summary> public class Proper tychagedeventargs:eventargs { public Propertychagedeventargs (string Propertyname,object oldvalue,object newvalue) { propertyname = propertyname; OldValue = oldvalue; &nbs P NewValue = newvalue; } public bool Cancel {get; set;} public string PropertyName {get; private set;} public object OldValue {get; private set;} public object NewValue {get; set;} }
Implementing custom property changes through C # Triggers custom events, understanding custom events and their triggering procedures
