Compare DataGridView cell values in C#

Hi mostafasalama145,

You need to execute FOR EACH loop through the DataGridView rows and perform check.

Code 

private void Form1_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[2] { new DataColumn("Num1", typeof(int)), new DataColumn("Num2", typeof(int)) });
    dt.Rows.Add(51, 62);
    dt.Rows.Add(45, 24);
    dt.Rows.Add(66, 02);
    dt.Rows.Add(24, 78);
    dt.Rows.Add(78, 69);
    dt.Rows.Add(44, 33);
    dataGridView1.DataSource = dt;

    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
        int value1 = Convert.ToInt32(row.Cells[0].Value);
        int value2 = Convert.ToInt32(row.Cells[1].Value);
        if (value1 > value2 )
        {
            row.Cells[1].Style.BackColor = Color.Red;
        }
        else
        {
            row.Cells[0].Style.BackColor = Color.Red;
        }
    }
}

Screenshot