see th value of points in chart when hovering mouse on

Question

3.71/5 (4 votes)

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Hi.I have a chart in my project.I want the user to see the value of each point in a tooltip ,when hovering the mouse on it.How can I do that?
Edit:
Some One sent me the following codes,I tried but I couldn't improve it.

C#

Point? prevPosition = null; 
ToolTip tooltip = new ToolTip();  
void chart1_MouseMove(object sender, MouseEventArgs e) 
{
     var pos = e.Location;
     if (prevPosition.HasValue && pos == prevPosition.Value)
         return;
     tooltip.RemoveAll();
     prevPosition = pos;
     var results = chart1.HitTest(pos.X, pos.Y, false,                                  
 ChartElementType.PlottingArea);
     foreach (var result in results)
     { 
        if (result.ChartElementType == ChartElementType.PlottingArea)
         {
             var xVal = result.ChartArea.AxisX.PixelPositionToValue(pos.X);
                    var yVal = result.ChartArea.AxisY.PixelPositionToValue(pos.Y); 
                    tp.Show("X=" + xVal + ", Y=" + yVal, this.chart2, pos.X, pos.Y - 15);
         }
     }
 }

It shows the values where ever I move the mouse.But I want the values be shown only when the pointer is near the series points.
Edit again:

C#

Point? prevPosition = null; 
ToolTip tooltip = new ToolTip();  
void chart1_MouseMove(object sender, MouseEventArgs e) 
{
     var pos = e.Location;
     if (prevPosition.HasValue && pos == prevPosition.Value)
         return;
     tooltip.RemoveAll();
     prevPosition = pos;
     var results = chart1.HitTest(pos.X, pos.Y, false,                                  
 ChartElementType.PlottingArea);
     foreach (var result in results)
     { 
        if (result.ChartElementType == ChartElementType.PlottingArea)
         {
             series2.ToolTip = "X=#VALX, Y=#VALY";
         }
     }
 }

But I want the values be shown only when the pointer is on the series points.

Posted 14-May-12 5:53am

ready to learn

Updated 17-May-12 20:48pm

v5

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Comments

Sergey Alexandrovich Kryukov 14-May-12 12:42pm

Good idea, my 5 for the question, but did you try anything?
--SA

Steve Echols 18-May-12 2:54am

I think you need to determine what Object was hit (such as a datapoint).

http://msdn.microsoft.com/en-us/library/system.windows.forms.datavisualization.charting.hittestresult.aspx

3 solutions

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Dave Kreskowiak · Answer 1 · 2012-05-14T07:21:00

Solution 1

The chart control you're using has to support this feature. So, what chart control are you using?

Posted 14-May-12 7:21am

Dave Kreskowiak

Comments

ready to learn 18-May-12 2:10am

MsChart

Dave Kreskowiak 18-May-12 8:03am

I believe the feature your want is not supported. You'll have to find another control to do this.

honeyashu · Answer 2 · 2012-05-17T20:48:00

Solution 2

May be this Article could Help :).. See the Tool Tip section or download the source for reference

A Guide to using MSChart for .NET[^]

honeyashu

Posted 17-May-12 20:48pm

honeyashu

linydeepak · Answer 3 · 2014-05-27T01:26:00

C#

void chart1_GetToolTipText(object sender, ToolTipEventArgs e)
        {   HitTestResult hitTestResult = chart1.HitTest(e.X, e.Y);
            
                if (hitTestResult.PointIndex >= 0 )
        if( hitTestResult.ChartElementType == ChartElementType.DataPoint)
        {    tooltip.RemoveAll();
              
                var results = chart1.HitTest(e.X, e.Y, false,
                                                   ChartElementType.DataPoint);
                foreach (var result in results)
                {
                    if (result.ChartElementType == ChartElementType.DataPoint)
                    {
                        var prop = result.Object as DataPoint;
                        if (prop != null)
                        {
                            var pointXPixel = result.ChartArea.AxisX.ValueToPixelPosition(prop.XValue);
                            var pointYPixel = result.ChartArea.AxisY.ValueToPixelPosition(prop.YValues[0]);

                            // check if the cursor is really close to the point (2 pixels around the point)
                            if (Math.Abs(e.X - pointXPixel) < 2 &&
                                Math.Abs(e.Y - pointYPixel) < 2)
                            {
                                tooltip.Show(prop.XValue +
                                    "," + prop.YValues[0], chart1,
                                    e.X, e.Y - 15);
                            }
                        }
                    }
                }
            }
        }