C# 查找图表中点的值
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finding the value of the points in a chart
提问by Asma Good
I have made a chart on my form.
我在表格上做了一张图表。
I want the user to see the value, x_valueand y_valueof each part in a balloon by clicking on that part.
我希望用户通过单击该零件来查看气球中每个零件的value,x_value和y_value。
The ballon shoud disappear when the user moves the mouse.
当用户移动鼠标时，气球应该消失。
How can I do that?
我怎样才能做到这一点？
采纳答案by digEmAll
You could do something like this:
你可以这样做：
ToolTip tooltip = new ToolTip();
Point? clickPosition = null;
void chart1_MouseMove(object sender, MouseEventArgs e)
{
if (clickPosition.HasValue && e.Location != clickPosition)
{
tooltip.RemoveAll();
clickPosition = null;
}
}
void chart1_MouseClick(object sender, MouseEventArgs e)
{
var pos = e.Location;
clickPosition = 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);
tooltip.Show("X=" + xVal + ", Y=" + yVal,
this.chart1, e.Location.X,e.Location.Y - 15);
}
}
}
Result:
结果：
EDIT :
编辑 ：
to show the tooltip whenever the mouse move, you can use the following code:
要在鼠标移动时显示工具提示，您可以使用以下代码：
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);
tooltip.Show("X=" + xVal + ", Y=" + yVal, this.chart1,
pos.X, pos.Y - 15);
}
}
}
Note that this shows the tooltip on any position of the chart. If you want to show it only when the mouse is near to a series point, you can use a mschart functionality e.g. :
请注意，这会在图表的任何位置显示工具提示。如果您只想在鼠标靠近系列点时显示它，您可以使用 mchart 功能，例如：
yourSeries.ToolTip = "X=#VALX, Y=#VALY";
(further examples here)
（此处有更多示例）
