Question

i want to test rows color changing in DataGridView, so i wrote that code:

dataGridView1.Rows.Add(new object[] { "Uno", "No" });
dataGridView1.Rows.Add(new object[] { "Due", "No" });
dataGridView1.Rows.Add(new object[] { "Tre", "Yes" });
dataGridView1.Rows.Add(new object[] { "Quattro", "No" });
dataGridView1.Rows.Add(new object[] { "Cinque", "Yes" });

private void button1_Click(object sender, EventArgs e)
    {            
        foreach (DataGridViewRow row in dataGridView1.Rows)
        {
            if (row.Cells[1].Value.ToString() == "Yes")
                row.DefaultCellStyle.ForeColor = Color.Red;
            else
                row.DefaultCellStyle.ForeColor = Color.Green;
        }
    }

So, there are five rows and two columns. But when i tried to change color, it gave me a NullReference exception, saying that row.Cells[1] values are null. What’s wrong?

Answer 1

Erase “toString()” in your if and it is working.
Value is returning a string 😉

UPDATE:
Use this. It will cast the object into a string

 if ((string)row.Cells[1].Value == "Yes")
                row.DefaultCellStyle.ForeColor = Color.Red;
            else
                row.DefaultCellStyle.ForeColor = Color.Green;