写法一：
string sql = "select * from tbColumns";
using (SqlConnection conn = new SqlConnection(PubVarData.ConnectionString))
{
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
using (SqlDataAdapter adapter = new SqlDataAdapter())
{
adapter.SelectCommand = cmd;
DataSet ds = new DataSet();
adapter.Fill(ds);
string jSon = DataConvertHelper.convertDataTableToString(ds.Tables[0]);
return jSon;
}
}
写法二：
string sql = "select * from tbColumns";
using (SqlConnection conn = new SqlConnection(PubVarData.ConnectionString))
{
conn.Open();
using (SqlCommand cmd = new SqlCommand { Connection = conn, CommandText = sql, CommandType = CommandType.Text })
{
using (SqlDataAdapter adapter = new SqlDataAdapter { SelectCommand = cmd })
{
using (DataSet ds = new DataSet())
{
adapter.Fill(ds);
string jSon = DataConvertHelper.convertDataTableToString(ds.Tables[0]);
return jSon;
}
}
}
}
