Begininvoke中嵌套Invoke发生了阻塞,求解决

Question

为什么button2_Click()不能正确执行?

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 WindowsFormsApplication35
{
    public partial class Form2 : Form
    {

        public Form2()
        {
            InitializeComponent();
            Button btn1 = new Button();
            btn1.Text = "btn1"; btn1.Dock = DockStyle.Left;
            btn1.Click += this.button1_Click;
            this.Controls.Add(btn1);
            Button btn2 = new Button();
            btn2.Text = "btn2";  btn2.Dock = DockStyle.Left;
            btn2.Click += this.button2_Click;
            this.Controls.Add(btn2);           
        }


        /// <summary>
        /// 可以正确执行
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            ((Button)sender).Text = "Running...";
            dlg_void_void pf = new dlg_void_void(SetFormText);
            var aysncRst = this.BeginInvoke(pf);
            this.EndInvoke(aysncRst);
            ((Button)sender).Text = "Complete";
        }
        /// <summary>
        /// 在执行后阻塞在SetFormText()的 this.Invoke(pf);
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button2_Click(object sender, EventArgs e)
        {
            ((Button)sender).Text = "Running...";
            dlg_void_void pf = new dlg_void_void(SetFormText);
            var aysncRst = pf.BeginInvoke(null, null);
            pf.EndInvoke(aysncRst);
            ((Button)sender).Text = "Complete";

        }
        delegate void dlg_void_void();
        private void SetFormText()
        {
            if (this.InvokeRequired)
            {
                dlg_void_void pf = new dlg_void_void(SetFormText);
                this.Invoke(pf);
                return;
            }

            var sum = 0;
            for (int i = 0; i < 10; i++)
            {
                sum += i;
            }
            this.Text = sum.ToString();
        }
    }
}

Answer 1

你写
pf.EndInvoke(aysncRst);
能不阻塞么？

去掉这一行，把((Button)sender).Text = "Complete";写在BeginInvoke的第二个参数的委托中

这里有个例子
http://www.bubuko.com/infodetail-578212.html