写这样的代码：

using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public class Form1 : Form
    {
        private readonly Button button1 = new Button();
        private readonly ComboBox comboBox1 = new ComboBox();
        private readonly TextBox textBox1 = new TextBox();

        public Form1() {
            SuspendLayout();
            textBox1.Location = new Point(21,51);
            button1.Location = new Point(146,49);
            button1.Text = "button1";
            button1.Click += button1_Click;
            comboBox1.Items.AddRange(new[] {"1","2","3","4","5","6"});
            comboBox1.Location = new Point(21,93);
            AcceptButton = button1;
            Controls.AddRange(new Control[] {textBox1,comboBox1,button1});
            Text = "Form1";
            ResumeLayout(false);
            PerformLayout();
        }

        private void button1_Click(object sender,EventArgs e) {
            comboBox1.DroppedDown = true;
        }
    }
}

然后,运行应用程序.将鼠标光标放在表单上,​​不要再触摸鼠标.开始在TextBox中键入一些东西 – 光标会隐藏起来.当您按Enter键 – 事件抛出和ComboBox将被删除.但现在光标不会出现,即使你移动它！只有当您点击某处时才会出现.

There我发现这个问题的讨论.但是没有什么好的解决方案

有什么想法吗？ 原文链接：https://www.f2er.com/csharp/95020.html