Can't draw line on win form.

George Loveless

For some reason my line wont draw on my windows form. If I place the code in a button event routine it works fine but it won't work when the window loads. I'm really confused! thanks:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace testForm
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public void Form1_Load(object sender, EventArgs e)
        {
            Pen myPen = new Pen(Color.Red);
            Graphics g = this.CreateGraphics();
            g.DrawLine(myPen, 20, 30, 10, 50);
            //this.Refresh();   //doesn't work if I add this.
        }

    }
}

3 Replies

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Mahesh Chand17y ago
Accepted answer
You need to put this code on On_Paint event handler of the form.
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George Loveless17y ago
Thanks guys... got it working. although I couldn't find a event function named "on_paint()", I just clicked on the form and then in the properited menu double clicked on the paint event.. this created a form1_paint function. This might be the same thing as on_paint but I'm sure. Thanks.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace t
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Pen myPen = new Pen(Color.Red);
            Graphics g = this.CreateGraphics();
            g.DrawLine(myPen, 20, 30, 10, 50);
        }
    }
}
0
jabir eriyaden17y ago
protected override void OnPaint(PaintEventArgs e) { e.Graphics.DrawLine();//use parameter base.OnPaint(e); } paint event fire Every time when form refresh
0