C# DBHelper问题

发布网友发布时间：2022-04-08 01:22

共2个回答

热心网友时间：2022-04-08 02:52

你从哪里得到DBHelper?
就到哪里找帮助啊.
可以推测,其GetScalar()方法执行sql语句,然后返加一个单值.
我以前用过动软.net代码生成器,其SQLDBHelper类有相似的方法，但不会完全相同，实在不行就参考一下吧。

热心网友时间：2022-04-08 04:10

public class DBHelper
{
//属性:数据库链接对象
private static SqlConnection conn;
public static SqlConnection Conn
{
get
{
string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
if (conn == null)
conn = new SqlConnection(connstr);
if (conn.State == ConnectionState.Closed)
conn.Open();
if (conn.State == ConnectionState.Broken)
{
conn.Close();
conn.Open();
}
return conn;
}
}

//方法:查询,DataReader
public static SqlDataReader GetReader(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
return cmd.ExecuteReader();
}

public static SqlDataReader GetReader(string SqlStr,SqlParameter[] paras)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
cmd.Parameters.AddRange(paras);
return cmd.ExecuteReader();
}

//查询:DataTable
public static DataTable GetTable(string SqlStr)
{
SqlDataAdapter dap = new SqlDataAdapter(SqlStr, Conn);
DataSet ds = new DataSet();
dap.Fill(ds);
conn.Close();
return ds.Tables[0];

}

//增删改
public static bool Execute(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
int result = cmd.ExecuteNonQuery();
conn.Close();
return result > 0;
}

//返回首行首列
public static object GetScalar(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
object obj = cmd.ExecuteScalar();
conn.Close();
return obj;
}