测量按钮1单击和按钮2单击之间的时间

Question

I need to measure the time between button 1 click and button 2 click. I know that I can use Datetime.Now but any variable I assign, I can only use in one eventhandler. I searched on the internet but all i could find was using a stopwatch, but that doesn't seem to work anymore in Visual Studio 2017.

Answer 1

You can use a Stopwatch instance or DateTime calculation. If you want to use Stopwatch you also have to import the containing namespace.

using System.Diagnostics;

Either way, you have to put your variable in a scope above the eventhandlers so that both eventhandlers have access to it. Here is a Winforms example that uses both methods, but it can easily be translated to other scenarios.

using System;
using System.Diagnostics;
using System.Windows.Forms;

namespace WindowsFormsApp1 {
    public partial class Form1 : Form {
        private DateTime from;
        private Stopwatch watch = new Stopwatch();

        public Form1() {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e) {
            from = DateTime.Now;
            watch.Restart();
        }

        private void button2_Click(object sender, EventArgs e) {
            watch.Stop();
            MessageBox.Show(
                "Date subtraction: " + DateTime.Now.Subtract(from).ToString() + Environment.NewLine +
                "Stopwatch: " + watch.Elapsed.ToString());

        }
    }
}

Answer 2

Use Stopwatch

Stopwatch _sw = new Stopwatch();

void Button1_Click(sender, e)
{
    if (_sw.IsRunning) 
        _sw.Stop();
    _sw.Reset();
    _sw.Start();
}


void Button2_Click(sender, e)
{
    if (_sw.IsRunning)   
        _sw.Stop();
    MessageBox.Show(_sw.Elapsed);
}

If you in Web Forms, you can stuff your stop watch into Session . And in REST, well, you can use runtime caching.