一：ADO.NET实现三层架构
不用三层的普通的查询写法：
string sql = string.Format("select * from Studnet where StuName like ‘%{0}%‘", txtName.Text);
string strconn = "server=.;database=MySc;uid=sa;pwd=123456";
SqlConnection conn = new SqlConnection(strconn);
SqlDataAdapter da = new SqlDataAdapter("select * fromStuden", conn);
DataSet ds = new DataSet();
try
{
da.Fill(ds);
// dataGridView1.DataSource = ds.Tables[0];
DataTable dt = ds.Tables[0];
txtName.Text = dt.Rows[0]["Name"].ToString();
}
catch (Exception)
{
throw;
}
普通删除的写法：
SqlConnection conn = new SqlConnection("server=.;database=MySc;uid=sa;pwd=123456");
string id = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();
string sql = "delect from Student where stNO=" + id;
SqlCommand comm = new SqlCommand(sql,conn);
conn.Open();
修改的普通写法：
string strsql = @"UPDATE Student SET [StuName]=‘0‘ WHERE [StuNO]={3}";
string id = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();
string sql = string.Format(strsql, txtName.Text, id);
SqlConnection conn = new SqlConnection("server=.;database=MySc;uid=sa;pwd=123456");
SqlCommand com = new SqlCommand(sql, conn);
try
{
conn.Open();
com.ExecuteNonQuery();
//刷新数据
}
catch (Exception)
{
throw;
}
finally {
conn.Close();
}
一个简单的DbHelper：
private static SqlConnection conn = new SqlConnection("server=.;database=Mys,uid=sa;pwd=123456"); public static int ExecuteSQL(string strsql) { SqlCommand comm = new SqlCommand(strsql, conn); try { conn.Open(); return comm.ExecuteNonQuery(); } catch (Exception ex) { throw ex; } finally { conn.Close(); } } public static int GetDataTable(string strsql) { SqlDataAdapter da = new SqlDataAdapter(strsql, conn); DataSet ds = new DataSet(); try { da.Fill(ds); return ds.Tables[0]; } catch (Exception ex) { throw ex; } } /// <summary> /// 返回一个单一的值 /// </summary> /// <param name="strsql">传入的是select打头的sql语句（select count（*），select max（..））</param> /// <returns>返回的是Object类型</returns> public static object GetSingle(string strsql) { SqlCommand comm = new SqlCommand(strsql, conn); try { conn.Open; return comm.ExecuteScalar(); } catch (Exception ex) { throw ex; } finally { conn.Close(); } }
二：用OOP实现三层架构
三：应用抽象工厂+反射实现通用数据源的设计
原文：http://www.cnblogs.com/sunliyuan/p/5797564.html