. Net event in the class, why can it be defined as static? However, the delegate type is not allowed.

I have a form and a clsevent class,
An event is registered in the form.
A delegate + event is defined in the clsevent class, and an event is thrown. But why cannot I obtain this event in the form ??

 

Later, I modified the event defined in the clsevent class to static, and the form can be obtained?

Clsevent class public class clsevent {Public Delegate void showsometing1 (string strtxtbox); public static event showsometing1 btnclick1; private string _ strcontent; Public String strcontent {get {return _ strcontent ;} set {// when the attribute is changed, the event _ strcontent = value is triggered; // The event is triggered in the event issuer. If (btnclick1! = NULL) {btnclick1 (_ strcontent );}}}

 

 Form1_Load

clsEvent m_clsEvent = new clsEvent();

// Form registers the event m_clsevent. btnclick1 + = new m_clsevent. showsometing1 (textboxchange) to the class)

Private void button#click (Object sender, eventargs e) {// modify attributes to stimulate events. M_clsevent. strcontent = This. textbox1.text;} public void textboxchange (string strcontent) {this.txt class. Text = strcontent ;}