How to draw lines in C#?

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I have a text file with XY coordinates.
For example these are the points in my file

-23.68 0.09
-23.67 0.76
-23.66 1.43
-23.68 2.1
-23.6 2.78
-23.58 3.45

My first line should be drawn from Point 1(-23.68 , 0.09) to Point 2 (-23.67 , 0.76) and the second line from Point 2(-23.67 , 0.76) to Point 3 (-23.66 , 1.43).

I want to draw these lines on a form.

What I have tried:

Im begiiner with C# hence I'm not aware of C# GUI

Posted 4-Mar-21 20:00pm

Member 14630688

Updated 4-Mar-21 23:40pm

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OriginalGriff · Answer 1 · 2021-03-04T21:22:00

Create a Panel on your form, and handle it's Paint event.

In the event handler, the second parameter includes a Graphics property, which allows you to draw on the panel surface.
Then it's just a case of calling DrawLine

C#

Graphics g = e.Graphics;
g.DrawLine(Pens.Black, new PointF(-23.68F, 0.09F), new PointF(-23.67F, 0.76F));
g.DrawLine(Pens.Black, new PointF(-23.67F, 0.76F), new PointF(-23.66F, 1.43F));

You may have to play with scaling and / or center points in order to see your data though, as Windows coordinates start with (0, 0) at teh top left corner, and increase down and right.

BillWoodruff · Answer 2 · 2021-03-04T23:09:00

Solution 2

First, your x,y Point values are all negative: why would you want lines that would not appear, if drawn, in any Control's Paint Event ?

Second, if you wish to have hit-detection on the lines you draw, there is another technique you can use: I'll post an example if you request it.

Posted 4-Mar-21 23:09pm

BillWoodruff

Ralf Meier · Answer 3 · 2021-03-04T23:40:00

What is the sense of your question ?
In my opinion your collection of points could be a Chart. If Yes : there is a free Tool (MSChart) availible in the Internet :
Download Microsoft Chart Controls for Microsoft .NET Framework 3.5 from Official Microsoft Download Center[^]
Here you only need to add the Points to the Chart ... (and you get your line)

How to draw lines in C#?

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