We Keep Coding

c# . If (timeElapsed == seconds) When button is clicked after random amount of seconds it has to change color

I'm trying to do something like https://www.humanbenchmark.com/ with android xamarin. I'm stuck with converting lifespan to integer? This is my piece of code:
private void AfterClicked()
{
ScreenClickButton.SetBackgroundColor(Android.Graphics.Color.Red);
Random rnd = new Random();
int seconds = rnd.Next(1, 11);
DateTime startTime1;
startTime1 = DateTime.Now;
TimeSpan timeElapsed = DateTime.Now - startTime1;
if (timeElapsed == seconds)
{
ScreenClickButton.SetBackgroundColor(Android.Graphics.Color.Green);
}
}

If you look at the docs for TimeSpan, you'll see that it has a seconds property
if (timeElapsed.Seconds == seconds)
However, this is probably not going to work: you are essentially creating two DateTime objects in a row and comparing them - they will not be identical but will also not differ by any meaningful amount, and certainly not by more than a second.
If you are trying to measure user reaction time, you probably want to establish the benchmark timestamp before they click the button, not after.

c# winforms chart shows values wrong [duplicate]

I try to draw Chart via C# with table as picture.
However, as you can see A4 data in date: 7 and 8/6 should stay with same 7 and 8/6 X-Axis, abnormal here all of them left to 5 & 6/6 X-Axis. Could you help me to fix it.
for (int i = 0; i < 14; i++)
{
string productname = dataGridView1.Rows[i].Cells[0].Value.ToString();
string datetime = dataGridView1.Rows[i].Cells[2].Value.ToString();
int para = Convert.ToInt16(dataGridView1.Rows[i].Cells[1].Value);
if (chart_dashboard.Series.IndexOf(productname) != -1)
{
chart_dashboard.Series[productname].Points.AddXY(datetime, para);
chart_dashboard.ChartAreas[0].AxisX.Interval = 1;
}
else
{
chart_dashboard.Series.Add(productname);
chart_dashboard.Series[productname].Points.AddXY(datetime, para);
chart_dashboard.ChartAreas[0].AxisX.Interval = 1;
}
}

A common mistake.
string datetime = dataGridView1.Rows[i].Cells[2].Value.ToString();
This is wrong! If you add the x-values as strings they all are added as 0 and the Series can't align them to the proper slots on the X-Axis. So they get added from left to right sequentially..
Instead simply add the x-values as the DateTimes they are supposed to be!
So if the Cells contain DateTime values use:
DateTime datetime = (DateTime) dataGridView1.Rows[i].Cells[2].Value;
If they don't, convert them to DateTime
DateTime datetime = Convert.ToDateTime(dataGridView1.Rows[i].Cells[2].Value);
To control the x-values type set the XValueType for each series:
chart_dashboard.Series[yourSeries].XValueType = ChartValueType.DateTime;
To control the way the axis labels are displayed set their formatting:
chart_dashboard[ChartAreas[0].AxisX.LabelStyle.Format = someDateTimeFormatString;
To create a string like "Week 1" you would
set the XValueType to int16
add the x-value as the week numbers
format it like ..axis.LabelStyle.Format = "Week #0";
To extract the number from your data split by space and Convert.ToInt16 !
If one really needs to insert sparse x-values as strings one would have to insert a dummy DataPoint at each gap in a series.
Creating a dummy DataPoint is simple:
DataPoint dp = new DataPoint() { IsEmpty = true};
But knowing where the gaps are in advance is the challenge! The 'best' way is to go over the data and filling in the before adding the points. Or go over it later and instead of adding, inserting the dummys at the gaps. Both is a lot more trouble than getting the data right in the first place!

Time Trackbar or Very Large Values using Trackbar

I am writing a vehicle tracking application using GMAP.NET
I want to display simultaneous movement of multiple vehicle markers based on date/time.
For this, I would like to use a Trackbar such that when the User slides the trackbar, the corresponding movement of multiple markers is shown.
I did the same application on the browser and it worked very well. I converted the datetime attribute of the marker tag to a UNIX Timestamp and then set the trackbar (NOUI Slider) values to the the UNIX Timestamp range.
But, Now I find that I cannot do this at all with the Windows Desktop C# Trackbar.
The problems are:
The trackbar is unable to take very large timestamp values. Eg. 5 years data.
Even after reducing the very large numbers, the trackbar still cannot take such high values and keeps lagging or crashing.
Eg. I need to show data for 5 years. In this case, my trackbar would have minimum value - 1262304000 (i.e. 01-01-2010) to 1425203100 (i.e. 01-03-2015 | 09:45).
But such large values just don't work with my trackbar.
I have even taken reduction eg. setting 1262304000 as 1 and then 162899100 (i.e. 1425203100 - 1262304000) becomes my maximum value.
But even this is very intensive and the trackbar does not work.
Please suggest if there is a time-trackbar which can show very a large datetimerange or how I can use a regular trackbar with very large values.
The code as follows -
A. The function to convert datetime to a UNIX Timestamp
public Int32 UnixTimeStampUTC(DateTime datetime)
{
Int32 unixTimeStamp;
DateTime zuluTime = datetime.ToUniversalTime();
DateTime unixEpoch = new DateTime(1970, 1, 1).ToUniversalTime();
unixTimeStamp = (Int32)(zuluTime.Subtract(unixEpoch)).TotalSeconds;
return unixTimeStamp;
}
B. Taking the DateTime from a DataTable by Concatenating Date & Time Columns and Adding a third Column to hold the Unix TimeStamp of the DateTime Column
for (int z = 0; z < dt.Rows.Count; z++)
{
if (reviseddt.Rows[z]["date"].ToString() != "")
{
dte = DateTime.Parse(reviseddt.Rows[z]["date"].ToString());
dteticks = UnixTimeStampUTC(dte);
}
else
{
dteticks = 0;
}
if (reviseddt.Rows[z]["time"].ToString() != "")
{
tm = DateTime.Parse(reviseddt.Rows[z]["time"].ToString());
tmticks = UnixTimeStampUTC(tm);
}
else
{
tmticks = 0;
}
Int32 fullDt = dteticks + tmticks;
reviseddt.Rows[z]["datetime"] = fullDt.ToString();
reviseddt.Rows[z]["datetimestring"] = reviseddt.Rows[z]["date"].ToString() + reviseddt.Rows[z]["time"].ToString();
C. Initalising the Trackbar by Getting the min and max values from the datetime column in the datatable and then taking the range as the difference between the min and max values. Hence, Trackbar range = 1 to (Max-Min)
string strminlevel = toplotDataTable.Compute("min(datetime)", String.Empty).ToString();
string strmaxLevel = toplotDataTable.Compute("max(datetime)", String.Empty).ToString();
Int32 minLevel = Convert.ToInt32(strminlevel);
Int32 maxLevel = Convert.ToInt32(strmaxLevel);
Int32 rangeint = maxLevel - minLevel;
trackBarMoveTarget.Maximum = rangeint;
trackBarMoveTarget.Minimum = 1;
trackBarMoveTarget.LargeChange = 100;
trackBarMoveTarget.SmallChange = 1;

There are two problems with using TrackBar at this kind of scale.
First you need to be able to move the track bar left and right, but if the SmallChange and LargeChange properties are too small then you may be making a lot of progress, but it simply doesn't show on the track bar. Try this for a start:
trackBarMoveTarget.Maximum = rangeint;
trackBarMoveTarget.Minimum = 1;
trackBarMoveTarget.LargeChange = rangeint / 50;
trackBarMoveTarget.SmallChange = rangeint / 200;
The other problem is that the TrackBar control tries to render helpful little tick marks along its length. By default the TickFrequency is 1 and the Maximum value is 10. When You set Maximum to 162899100 without changing TickFrequency then the poor TrackBar control has to try and render 162899100 tick marks and that takes a long time. Try this:
trackBarMoveTarget.TickFrequency = rangeint / 100;

Be realistic - the trackbar only has a resolution down to 1 pixel - most displays are, at the most 1920 pixels wide. Therefore the resolution only has to be 1920 - let's round it up to 2000.
Now you have a 5 year period = 5 * 365 + 1 (for the odd leap year) = 1826. This is almost equal to our original 2000 odd. So let's make it 1826.
So set the Minimum value to 0 and the Maximum to 1826.
When you get the track event you take the first date 01-01-2010 and add the value of the trackbar to it:
var firstDate = new DateTime(2010, 1, 1).Date;
var trackDate = firstDate + TimeSpan.FromDays(trackBar.Value);
easy and quick.

How to populate dropdownlist with hours in c#

I have to 2 dropdownlists and I want to populate them with their values as hours from 1 to 24. Then I want to calculate the difference between the two selected values. If i choose in the first dropdown let's say the hour value as 12 AND second value as 16 then the difference will be 4.
How can I achieve that in c#?
I'm developing a asp.net web application coded in C#.
Below is the code of how I populate my dropdownlist:
DateTime Date = DateTime.Today;
DateTime Time = DateTime.Now;
ListItem item1 = new ListItem(Time.ToShortTimeString(),
Time.ToShortTimeString());
for (int i = 0; i <= 48; i++)
{
ListItem item2 = new ListItem(Date.ToShortTimeString(),
Date.ToShortTimeString());
droplist.Items.Add(item2);
if (Date.CompareTo(Time) < 0 && Date.AddMinutes(30).CompareTo(Time) > 0)
droplist.Items.Add(item1);
Date = Date.AddMinutes(60);
}
How can I assign values to my dropdown, values being the hours?

Instead of adding the date/time string to the drop down, you may add the DateTime value itself. The dropdown displays its members by calling ToString(). The disadvantage here: you are not able to use another time format like ToShortTimeString().
Another way is to use the DateTime.TryParse method to convert back before calculating.

Secondary axis labels not working?

Okay so I have a datetime x-axis on an MSChart. I want to plot months below the first of each month and years below the change of a year. Here's what I have so far:
for (int i = 0; i < rdate.Length -1 ; i++)
{
if (rdate[i].Day == 01 && set == 0)
chart1.ChartAreas[0].AxisX.CustomLabels.Add(
rdate[i].AddDays(-20).ToOADate(), rdate[i].AddDays(20).ToOADate(),
Convert.ToString(rdate[i].ToString("MMMM")), 1, LabelMarkStyle.None);
set = 1;
if (rdate[i].Day > 01)
set = 0;
i++;
if (rdate[i].Year > rdate[i-1].Year)
chart1.ChartAreas[0].AxisX.CustomLabels.Add(
rdate[i].AddDays(-20).ToOADate(), rdate[i].AddDays(20).ToOADate(),
Convert.ToString(rdate[i].ToString("yyyy")), 2, LabelMarkStyle.None);
}
However for some reason this skips some months... The years do not show up at all.
rdate is a datetime array used to populate the x axis.
Here is an example of what my code does:
As you can see, the labels are behaving unexpectedly. I would also like to show a larger tick mark for these dates, and reduce the number of day labels based upon the date range, but I'm at a loss. Anyone done this sort of thing before?

I recently had a similar issue with MSChart when adding too many labels to the x-axis. The solution was reduce the number of ticks without losing data.
This approach worked for me but you will have to adapt it to your specific needs.
dataSeries.XValueType = ChartValueType.Auto;
dataSeries.Points.AddXY(record.DateTime, value);
I then determined the min and max dates for the given data to determine the preferred interval, your implementation will vary:
var totalDays = (maxDate.Value - minDate.Value).TotalDays;
if (totalDays < 60)
chartArea.AxisX.IntervalType = DateTimeIntervalType.Days;
else if (totalDays < 120)
chartArea.AxisX.IntervalType = DateTimeIntervalType.Weeks;
else
chartArea.AxisX.IntervalType = DateTimeIntervalType.Months;
Specify the AxisX label format:
In your case you might have to change the Format together with the interval.
chartArea.AxisX.LabelStyle.Format = Thread.CurrentThread.CurrentCulture.DateTimeFormat.ShortDatePattern;
Hopefully there are some key parts that will provide value for you but you still have to modify it for your particular needs.