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Question

请问如何计算出一段代码所需的执行时间！！ 
本人以前看到过这样的问题  可是没留心
 只记得  要获得一段程序执行前和后的时间  并相减就能得到这段代码所需的执行时间
  可具体怎么实现的   就不记得了
 
           诚请指教！

Answer 1

Use "TimeSpan" ,
Sample code as follows:
DateTime dtStart = DateTime.Now;
...TimeSpan ts = DateTime.Now - dtStart;
//ts.Ticks

Answer 2

//也可以使用Timer控件using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;namespace Example_1
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class frmTickCounter : System.Windows.Forms.Form
{
private System.Windows.Forms.Label lblComputer;
private System.Windows.Forms.Label lblApplication;
private System.Windows.Forms.GroupBox grpElapsed;
private System.Windows.Forms.Button btnClose;
private System.Windows.Forms.Timer tmrTickTimer;
private System.ComponentModel.IContainer components;
private int compuTime; public frmTickCounter()
{
InitializeComponent();
} /// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null) 
{
components.Dispose();
}
}
base.Dispose( disposing );
} #region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.grpElapsed = new System.Windows.Forms.GroupBox();
this.lblApplication = new System.Windows.Forms.Label();
this.lblComputer = new System.Windows.Forms.Label();
this.btnClose = new System.Windows.Forms.Button();
this.tmrTickTimer = new System.Windows.Forms.Timer(this.components);
this.grpElapsed.SuspendLayout();
this.SuspendLayout();
// 
// grpElapsed
// 
this.grpElapsed.Controls.Add(this.lblApplication);
this.grpElapsed.Controls.Add(this.lblComputer);
this.grpElapsed.Font = new System.Drawing.Font("Microsoft Sans Serif", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((System.Byte)(0)));
this.grpElapsed.Location = new System.Drawing.Point(8, 8);
this.grpElapsed.Name = "grpElapsed";
this.grpElapsed.Size = new System.Drawing.Size(600, 120);
this.grpElapsed.TabIndex = 0;
this.grpElapsed.TabStop = false;
this.grpElapsed.Text = "开机时长";
// 
// lblApplication
// 
this.lblApplication.Location = new System.Drawing.Point(16, 72);
this.lblApplication.Name = "lblApplication";
this.lblApplication.Size = new System.Drawing.Size(576, 26);
this.lblApplication.TabIndex = 1;
// 
// lblComputer
// 
this.lblComputer.Location = new System.Drawing.Point(16, 32);
this.lblComputer.Name = "lblComputer";
this.lblComputer.Size = new System.Drawing.Size(576, 26);
this.lblComputer.TabIndex = 0;
// 
// btnClose
// 
this.btnClose.Location = new System.Drawing.Point(488, 136);
this.btnClose.Name = "btnClose";
this.btnClose.Size = new System.Drawing.Size(115, 26);
this.btnClose.TabIndex = 1;
this.btnClose.Text = "关闭";
this.btnClose.Click += new System.EventHandler(this.btnClose_Click);
// 
// tmrTickTimer
// 
this.tmrTickTimer.Enabled = true;
this.tmrTickTimer.Interval = 20;
this.tmrTickTimer.Tick += new System.EventHandler(this.tmrTickTimer_Tick);
// 
// frmTickCounter
// 
this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
this.ClientSize = new System.Drawing.Size(616, 173);
this.Controls.Add(this.btnClose);
this.Controls.Add(this.grpElapsed);
this.Name = "frmTickCounter";
this.Text = "时钟";
this.Load += new System.EventHandler(this.frmTickCounter_Load);
this.grpElapsed.ResumeLayout(false);
this.ResumeLayout(false); }
#endregion /// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main() 
{
Application.Run(new frmTickCounter());
} private void frmTickCounter_Load(object sender, System.EventArgs e)
{
compuTime = Environment.TickCount;
} private void tmrTickTimer_Tick(object sender, System.EventArgs e)
{
//Environment类提供有关当前环境和平台的信息以及操作它们的方法
long curTickValue = Environment.TickCount;
long difference = curTickValue - compuTime;

long computerHours, computerMinutes, computerSeconds;
long applicationHours, applicationMinutes, applicationSeconds;

//converting milliseconds into hours, minutes and seconds computerHours = (curTickValue / (3600 * 999)) % 24;
computerHours = (curTickValue / (3600 * 999)) % 24;
computerMinutes = (curTickValue / (60 * 999)) % 60;
computerSeconds = (curTickValue / 999) % 60;

applicationHours = (difference / (3600 * 999)) % 24;
applicationMinutes = (difference / (60 * 999)) % 60;
applicationSeconds = (difference / 999) % 60; this.lblComputer.Text = String.Format("本计算机已运行了 {0} 小时 {1} 分 {2} 秒", computerHours.ToString(), computerMinutes.ToString(),
computerSeconds.ToString()); this.lblApplication.Text = String.Format("本应用程序已运行了 {0} 小时 {1} 分 {2} 秒",
applicationHours.ToString(), applicationMinutes.ToString(),
applicationSeconds.ToString()); } private void btnClose_Click(object sender, System.EventArgs e)
{
this.Close();
} }
}

Answer 3

能不能有一种比较精确的计算执行时间的啊
   我觉得有datetime精确度太低了   因为一般的程序执行都是毫秒级的

Answer 4

datetime 只能精确到秒......

Answer 5

是2.0的就推荐楼上的吧，可以精确到nanosecond

Answer 6

public long GetTime(int num)
        {
            long dtStart = DateTime.Now.Ticks;
            ArrayList aa = new ArrayList();            for (int i = 1; i < num; i++)
            {
                if (sss(i))
                {
                    aa.Add(i);
                }
            }
            int count = aa.Count;
            string dd = aa[count - 1].ToString();
            long dtEnd = DateTime.Now.Ticks;
            long ts = dtEnd - dtStart;
            return ts;
 }
  返回值ts怎么转化为毫秒呢？？

Answer 7

Use "TimeSpan" ,
Sample code as follows:
DateTime dtStart = DateTime.Now;
...TimeSpan ts = DateTime.Now - dtStart;
//ts.Milliseconds

Answer 8

DateTime dtStart = DateTime.Now;
  这样就有问题啊   DateTime.Now取值不精确
  我要用datetime.now.ticks   可这是长整形....长整形怎么转化为毫秒呢

Answer 9

除以一万得到毫秒数，刚才说过了，是nanosecond