CODEWITHSUNDEEP
c#graphicsdatagridview
Ruchir Sharma
Ruchir Sharma

Reputation: 949

Looping through all the cells in a datagridview

This is my code:

private void button1_Click(object sender, EventArgs e)
    {
        Graphics g = this.CreateGraphics();
        Pen p = new Pen(Brushes.Blue);
        foreach (DataGridViewRow dr in dataGridView1.Rows)
        {
            float p1x = float.Parse(dr.Cells["p1x"].Value.ToString());
            float p1y = float.Parse(dr.Cells["p1y"].Value.ToString());
            float p2x = float.Parse(dr.Cells["p2x"].Value.ToString());
            float p2y = float.Parse(dr.Cells["p2y"].Value.ToString());
            g.DrawEllipse(p, p1x, p1y, 10, 10);
            g.DrawEllipse(p, p2x, p2y, 10, 10);
            g.FillEllipse(Brushes.Black, p1x, p1y, 10, 10);
            g.FillEllipse(Brushes.Black, p2x, p2y, 10, 10);
            g.DrawLine(p, p1x, p1y, p2x, p2y);
        }
    }

On executing the above code, I'm getting the runtime exception "Object reference not set to an instance of an object." Please help.

Upvotes: 0

Views: 1001

Answers (1)

FlyingStreudel
FlyingStreudel

Reputation: 4464

More than likely one of your cells has a null value i.e.

dr.Cells["p1x"].Value == null

You can't use ToString() on null so you get that error.

Upvotes: 1

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