先写一个数据库统计函数
复制代码 代码如下:
public static int Count(string cityName)
{
string cmdText = "";
SqlConnection conn = new SqlConnection(DBH.DBA);
SqlCommand cmd = null;
cmdText = "Select count(*) From [Drugstore] Where CityName=@cityName ";
cmd = new SqlCommand(cmdText, conn);
cmd.Parameters.AddWithValue("@cityName", cityName);
conn.Open();
int total = (int)cmd.ExecuteScalar();
conn.Close();
return total;
}

刚开始全部函数调用是这样一个个写出来的，后来熟悉了 用SqlHelp方便好多，在后来就直接用动软.net代码生成器了，发现对原先的这些越来越陌生了 ，现在大致整理一下，和上面重复的代码部分省略。
1. 添加数据
复制代码 代码如下:
DrugstoreInfo info = new DrugstoreInfo();
cmd.Parameters.AddWithValue("@ID",info.ID);
try
{
conn.Open();
return cmd.ExecuteNonQuery();
}
catch
{
throw;
}
finally
{
conn.Close();
}

.dataset 数据分页
复制代码 代码如下:
public static DataSet indexQuery(int pageIndex, int pageSize)
{
..
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
da.Fill(ds, (pageIndex - 1) * pageSize, pageSize, "Table1");
return ds;
}

. 获得最大值
复制代码 代码如下:
public static int GetMax()
{
string cmdText = "select Max(Id) from Application ";
..
try
{
conn.Open();
Object obj = cmd.ExecuteScalar();
if (obj == null || obj is DBNull)
{
return 1;
}
return (int)obj + 1;
}
catch
{
throw;
}
finally
{
conn.Close();
}
}

. select 选择
复制代码 代码如下:
public static ApplicationInfo Select(int id)
{
string cmdText = "select ID from Application where ID=@ID";
SqlConnection conn = new SqlConnection(DBH.ConnString);
SqlCommand cmd = new SqlCommand(cmdText, conn);
ApplicationInfo info = new ApplicationInfo();
cmd.Parameters.AddWithValue("@ID", id);
conn.Open();
using (IDataReader dr = cmd.ExecuteReader())
{
if (dr.Read())
{
info.ID = (int)dr["ID"];
}
dr.Close();
}
conn.Close();
return info;
}

.delete 删除
复制代码 代码如下:
public static int Del(int id)
{
string cmdText = "Delete from Application Where ID= @ID";
SqlConnection conn = new SqlConnection(DBH.ConnString);
SqlCommand cmd = new SqlCommand(cmdText, conn);
cmd.Parameters.AddWithValue("@ID", id);
conn.Open();
return cmd.ExecuteNonQuery();
conn.Close();
}

. update 修改
复制代码 代码如下:
public static int Update(ApplicationInfo info)
{
string cmdText = "Update Application Set City=@city Where ID=@ID";
SqlConnection conn = new SqlConnection(DBH.ConnString);
SqlCommand cmd = new SqlCommand(cmdText, conn);
cmd.Parameters.AddWithValue("@ID", info.ID);
try
{
conn.Open();
return cmd.ExecuteNonQuery();
}
catch
{
throw;
}
finally
{
conn.Close();
}
}

.配置
复制代码 代码如下:
public class DBH
{
private DBH() { }
private static readonly string _DBA = ConfigurationManager.ConnectionStrings["DBA"].ConnectionString;
public static string DBA
{
get { return _DBA; }
}
}

附: configurationManager 需要命名空间 using System.Configuration 和添加引用System.Configuration 双重操作。