C#操作数据库

C#连接数据库，并查询

    //连接数据库的连接符的默认必须参数：“Server=服务器地址或者服务器名（.代表本机）;Database=数据库名;User ID=用户名称;Password=密码（不解释）”这四个参数是必须的。至于其他的参数自己也不是很懂。日后补充。
            string connectionString = "Server=.;Database=CCTV;User ID=sa;Password=123456;MultipleActiveResultSets=True";
            SqlConnection con = new SqlConnection(connectionString);
            //操作数据库前，打开数据库连接，这里也可以使用try catch语句捕抓数据库连接异常
            con.Open();

            //string a = GetElename().Replace('-', '_');
            //string[] arr = a.Split(',');
            //for (int i = 0; i < arr.Length - 1; i++)
            //{

           //数据库操作语句，最常见的select insert delete update 四种语句。
                string sqlstring = "select Shape.STX ,Shape.STY ,Shape.Z from " + arr[i] + " order by Shape.Z";
                //string txtpath = @"F:\shp1\"+arr[i]+".txt";
            //对于数据库的查询方式有多种一下是一种
                SqlCommand sqlCommand = new SqlCommand();
            //为command制定数据库连接
                sqlCommand.Connection = con;
            //为command制定查询语句
                sqlCommand.CommandText = sqlstring;
                SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();
                sqlDataAdapter.SelectCommand = sqlCommand;
                DataSet dataset = new DataSet();
                DataTable datatable = new DataTable();
                SqlCommandBuilder sqlCommandBuilder = new SqlCommandBuilder(sqlDataAdapter);
                sqlDataAdapter.Fill(dataset, "t1");
                datatable = dataset.Tables[0];
                StringBuilder sb = new StringBuilder();
                sb.Append("Polyline" + Environment.NewLine);
                for (int j = 0; j < datatable.Rows.Count-1; j++)
                {
                    sb.Append(j.ToString()+" 0"+Environment.NewLine);
                    sb.Append("0 "+datatable.Rows[j][0]+" "+datatable.Rows[j][1]+" "+datatable.Rows[j][2]+" "+"0.0"+Environment.NewLine);
                    sb.Append("1 "+datatable.Rows[j+1][0] + " " + datatable.Rows[j+1][1] + " " + datatable.Rows[j+1][2] + " " + "0.0" + Environment.NewLine);
                    Console.Write(datatable.Rows[j][0]);
                }
                sb.Append("END");

 

 

通过C#读取shapefile文件可以根据一定的条件对shapefile的属性进行查询。但貌似查询完的结果不能按照我想要的要求进行排序，有些郁闷。试图通过借用.Net里的DataTable对象暂时存储查询到的结果（这个结果不包含shape字段）。如果知道如何对shapefile查询结果进行排序的更好的方法也可以留言指导一下。

但在利用DataTable的时候排序也遇到了一些问题，DataTable貌似不能直接进行排序。只要借助DataView的sort属性进行排序。

DataView dv = dt.DefaultView; 
dv.Sort = "c1 Asc"; 
DataTable dt2 = dv.ToTable();

或者
dt.DefaultView.Sort = "Z asc";
//DataTable dtcopy = dt.DefaultView.Table.Copy();
DataTable dtsort = dt.DefaultView.ToTable();

 参考：http://www.cnblogs.com/fmxyw/archive/2008/10/08/1306554.html

 

代码片段，获取查询的结果DataTable返回

        private DataTable GetDataBaseInfo(string whereclause)
        {
            string connectionString = ConfigurationManager.AppSettings["connection"];
            SqlConnection con = new SqlConnection(connectionString);
            con.Open();
            string sqlstring = "SELECT [NAME],[ELEVATORNAME] FROM [ELEVATORNAME] WHERE NAME='" + whereclause + "'";
            SqlCommand sqlCommand = new SqlCommand();
            sqlCommand.Connection = con;
            sqlCommand.CommandText = sqlstring;
            SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();
            sqlDataAdapter.SelectCommand = sqlCommand;
            DataSet dataset = new DataSet();
            DataTable datatable = new DataTable();
            SqlCommandBuilder sqlCommandBuilder = new SqlCommandBuilder(sqlDataAdapter);
            sqlDataAdapter.Fill(dataset, "t1");
            datatable = dataset.Tables[0];
            return datatable;
        }