c# - How To Search For a DataPoint on the X-Axis, and then be able to change the Y Value? -

i creating chart generates different data points adding x-axis values in loop in 1 series.

in series want able to:

• search see if series "total cost" has data point @ same point string "starttime"
• if chart has no values @ all, addxy of point series
• if chart has value @ "starttime", add value current y value
• if chart has no value @ "starttime", addxy point series

here code have been trying use far:

using system.windows.forms.datavisualization.charting;  // ...  public datetime starttime; public datetime endtime; public datetime totaltime;  private void comboboxstart_selectedindexchanged(object sender, eventargs e)     {         string format = "hh:mm";         starttime = datetime.parseexact(comboboxstart.text, format, system.globalization.cultureinfo.invariantculture);     }  private void picturebox1_mouseup(object sender, mouseeventargs e) {     if (textboxtotaltime.text != "")     {         string format = "hh:mm";         totaltime = datetime.parseexact(             comboboxfinish.text, format,              system.globalization.cultureinfo.invariantculture);         charttimespan.series.add(textboxname.text);                       while(starttime <= endtime)         {                             charttimespan.series[textboxname.text].points.addxy(starttime, 6);             starttime = starttime.addminutes(15);              datapoint datapointx = charttimespan.series[textboxname.text].points                 .findbyvalue((starttime).tooadate(), "x");              if(charttimespan.series["total cost"].points.contains(null))             {                 charttimespan.series["total cost"].points.addxy(starttime, 6);             }             else if (!(charttimespan.series["total cost"].points.findbyvalue((starttime).tooadate(), "x") == null))             {                 charttimespan.series["total cost"].points.;             }             else             {                 charttimespan.series["total cost"].points.addxy(starttime, 6);             }             }          charttimespan.legends.add(textboxname.text);         charttimespan.series[textboxname.text].charttype = seriescharttype.line;     }     textboxname.text = "";     comboboxstart.text = "";     comboboxfinish.text="";     textboxtotaltime.text = ""; } 

cheers help, or if think should using different approach!

instead of searching values inside chart, can tricky @ times due formatting, prefer use chart.series["name"].points.databind more managable collection. in experience makes sense when work dynamic data; rather storing data in chart have chart display (processed) data.

for type of solution first fashion type of data-object hold relevant values:

public class chartitem {     public double value { get; set; }     public datetime time { get; set; }      public chartitem(datetime time, double value)     {         value = value;         time = time;     } } 

and in form have like:

public list<chartitem> chartitems;  public form1() {     initializecomponent();      chart1.series[0].points.clear();     chartitems = new list<chartitem>();     chartitems.add(new chartitem(datetime.today, 1);     chartitems.add(new chartitem(datetime.today.addminutes(15), 2); // "or something"     ...     chart1.series[0].points.databind(chartitems, "time", "value", "");     chart1.chartareas[0].axisx.labelstyle.format = "yyyy-mm-dd hh:mm"; } 

and add value in private void picturebox1_mouseup:

datetime time = datetime.parseexact(textbox1.text, "yyyy-mm-dd hh:mm", system.globalization.datetimeformatinfo.invariantinfo);  const double valuetoadd = 1;  chartitem item = chartitems.singleordefault(x => x.time == time);  if (item == null) // no previous time in series {        item = new chartitem(time, valuetoadd);     chartitems.add(item); } else // add previous time     item.value += valuetoadd;  chart1.series[0].points.databind(chartitems, "time", "value", ""); // update chart