change color3

两种方法
第一种
DataGridview1.Rows[i].DefultCellStyle.backcolor
第二种
AlternatingRowsDefutCellstyle 属性
获取或设置应用于DataGridview的奇数行的默认单元格样式。
 
RowsDefultCellStyle 属性
  获取或设置应用于DataGridview的行单元格的默认样式。
 
        private void Form1_Load(object sender, EventArgs e)
        {
            string str = "server=192.168.100.222;user=sa;pwd=p@ssw1rd;database=pwd1";
            SqlConnection mycon = new SqlConnection(str);
            try
            {
                mycon.Open();
                DataSet mydt = new System.Data.DataSet();//建立填充数据库
                SqlDataAdapter mydpt = new SqlDataAdapter("select * from book",mycon);//建立适配器
                mydpt.Fill(mydt);
                dataGridView1.DataSource = mydt.Tables[0];//数据源绑定的是表不是数据库，所以要指定表，索引值从0开始  说明book这个表是数据库中第一个表
 
                for (int i = 0; i < dataGridView1.Rows.Count; i++)
                {
                    if (i % 2 == 0)
                    {
                        this.dataGridView1.Rows[i].DefaultCellStyle.BackColor = Color.Beige;
                    }
                    else
                    {
                        this.dataGridView1.Rows[i].DefaultCellStyle.BackColor = Color.Red;
                     
                    }
                }
 
            }
            catch (Exception ex)
            {
 
                MessageBox.Show(ex.Message);
            }
            finally
            {
                mycon.Close();
             
            }
        }