Question

找不到EventArgs类型扩展方法“Cancle”（是否缺少using）指令或程序集引用）

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_FormClosing(object sender, EventArgs e)
{
DialogResult d = MessageBox.Show("是否关闭窗体", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
if (d == DialogResult.Yes)
{
e.Cancel = false;
}
else
{
e.Cancel = true;
}
}

Answer 1

你把这一句

private void Form1_FormClosing(object sender, EventArgs e)

改成

private void Form1_FormClosing(object sender, CancelEventArgs e)

Answer 2

正常情况下添加上using system；就能找到了