C # WinForm Base Button1_Click (object sender, EventArgs e) What is sender and its usage

1. UI

2. Code

1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.ComponentModel;4 usingSystem.Data;5 usingSystem.Drawing;6 usingSystem.Linq;7 usingSystem.Text;8 usingSystem.Threading.Tasks;9 usingSystem.Windows.Forms;Ten  One namespaceWindowsFormsApplication1 A { -      Public Partial classForm1:form -     { the          PublicForm1 () -         { - InitializeComponent (); -         } +  -         Private voidButton1_Click (Objectsender, EventArgs e) +         { A             //The Sender object type, which is loaded with Button1, is the key point.  atButton BTN =(Button) sender; -TextBox1.Text =btn. Text; -         } -  -         Private voidButton2_Click (Objectsender, EventArgs e) -         { in             //this sender contains Button2. - Button1_Click (sender, E); to         } +     } -}

3. Effect

C # WinForm Base Button1_Click (object sender, EventArgs e) What is sender and its usage