Winforms Chart - draw a allowed area on line chart

Question

How can I draw the gray area on the chart (allowed range of the signal)?
I use the Winforms and standard Microsoft System.Windows.Forms.DataVisualization classes.
It should be the custom range, the meaning that the starting Y point could be not zero only.
The points I get online, at run time, one by one.

UPDATE:

I tried the StripLine - it's ok, but I don't know how to define the starting point in 2d. It can be set on X only or on Y only. I tried to use the second chart (Area), but it's not what I need...

UPDATE2:
Thanks to @Reza Aghaei!!!

Here the code that works great:

void drawAllowedArea(Point startPoint, Point endPoint, PaintEventArgs e)
{
      var l = (float)chart1.ChartAreas[0].AxisX.ValueToPixelPosition(startPoint.X);
      var t = (float)chart1.ChartAreas[0].AxisY.ValueToPixelPosition(endPoint.Y);
      var r = (float)chart1.ChartAreas[0].AxisX.ValueToPixelPosition(endPoint.X);
      var b = (float)chart1.ChartAreas[0].AxisY.ValueToPixelPosition(startPoint.Y);
      var rect = RectangleF.FromLTRB(l, t, r, b);
      using (var br = new SolidBrush(Color.FromArgb(100, Color.Blue))) 
      {
           e.Graphics.FillRectangle(br, rect.X, rect.Y, rect.Width, rect.Height);
      }
      e.Graphics.DrawRectangle(Pens.Red, rect.X, rect.Y, rect.Width, rect.Height);
}

//and use this function in chart1_Paint event:
void chart1_Paint(object sender, PaintEventArgs e)
{
      drawAllowedArea(new Point(20, 50000), new Point(40, 100000), e);
}

END OF UPDATE ---------------------------------------------------------

Thank you a lot!

I tried the StripLine - it's ok, but I don't know how to define the starting point in 2d. It can be set on X only or on Y only. I tried to use the second chart (Area), but it's not what I need... In addition, (I'll add it to the question) it should visible at run time - I get points online, one by one. — Michael Vaysman, Dec 21 '16 at 13:32
[Stripline](http://stackoverflow.com/questions/38958646/winforms-chart-how-to-enable-background-color-gauge/38959173?s=6|0.1465#38959173) would also work as would a Rectangleannotation. But drawing is often good enough.. — TaW, Dec 22 '16 at 16:27

Reza Aghaei · Accepted Answer · 2016-12-21T14:08:33.843

You can handle Paint event of Chart control and draw a rectangle on it. To get coordinates of the rectangle based on x-axis and y-axis values you can use ValueToPixelPosition method of axis. For example:

void chart1_Paint(object sender, PaintEventArgs e)
{
    var l = (float)chart1.ChartAreas[0].AxisX.ValueToPixelPosition(3.7);
    var t = (float)chart1.ChartAreas[0].AxisY.ValueToPixelPosition(45);
    var r = (float)chart1.ChartAreas[0].AxisX.ValueToPixelPosition(7.2);
    var b = (float)chart1.ChartAreas[0].AxisY.ValueToPixelPosition(31);
    var rect = RectangleF.FromLTRB(l, t, r, b);
    using (var br = new SolidBrush(Color.FromArgb(100,Color.Blue)))
        e.Graphics.FillRectangle(br, rect.X, rect.Y, rect.Width, rect.Height);
    e.Graphics.DrawRectangle(Pens.Red, rect.X, rect.Y, rect.Width, rect.Height);
}

Above values are just random values for test, you should use actual values of your x-axis and y-axis:

l: left of the rectangle (from x-axis)
t: top of the rectangle (from y-axis)
r: right of the rectangle (from x-axis)
b: bottom of the rectangle (from y-axis)

If you know values are int, you can cast them to int instead of float which I used for test.

Winforms Chart - draw a allowed area on line chart

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