C#中sqlDataRead 的三种方式遍历读取各个字段数值的方法

2019-10-29 19:59:28

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数据库的查询分析器中写上如下代码：

create table studentname( id int  primary key identity(1,1) not null ,name nvarchar(500) not null)insert into studentname values('long')insert into studentname values('long')insert into studentname values('long')insert into studentname values('long')insert into studentname values('long')insert into studentname values('chao')insert into studentname values('chao')

--sql server 2012 通过。

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以下是第一种方法：

using System.Data; using System.Data.SqlClient;string constr = "server=localhost;uid=sa;pwd=longshicheng;database=Student";      SqlConnection conn = new SqlConnection(constr);      SqlCommand cmd = new SqlCommand("select * from studentname", conn);      conn.Open();      SqlDataReader rdr = cmd.ExecuteReader();      string makestr = "";      DataTable table = new DataTable();      table.Load(rdr); //数据表装入 dataReader 。      string result="";      for (int i = 0; i < table.Rows.Count; i++) // 遍历行      {        for (int j = 0; j < table.Columns.Count; j++) //遍历列        {          result += table.Rows[i][j].ToString(); //逐行逐列显示每个单元格的数值。        }        result += Environment.NewLine; //一行遍历完成就写入回车。      }      txtlab.Text = result;      /***************************************************************/

以下是第二种方法:

string constr = "server=localhost;uid=sa;pwd=longshicheng;database=Student";      SqlConnection conn = new SqlConnection(constr);      SqlCommand cmd = new SqlCommand("select * from studentname", conn);      conn.Open();      SqlDataReader rdr = cmd.ExecuteReader();      string makestr = "";      for (int k = 0; k < rdr.FieldCount; k++) //获取字段名称      {        makestr += rdr.GetName(k) + "/t"; //载入字段名称      }      makestr += Environment.NewLine; //换行      makestr = makestr + "---------------------------------------------"+Environment.NewLine;      while (rdr.Read()) //逐行读取每一笔记录      {        for (int t = 0; t < rdr.FieldCount; t++) //逐列读出        {          makestr = makestr + rdr[t].ToString() + "/t"; //累加每一行，也就是逐个字段读出对应的数值        }        makestr = makestr + Environment.NewLine; //又一行      }      txtinfo.Text = makestr;      rdr.Close(); //关闭      conn.Close();    }

以下是第三种方法：

string constr = "server=localhost;uid=sa;pwd=longshicheng;database=Student";      SqlConnection conn = new SqlConnection(constr);      SqlCommand cmd = new SqlCommand("select * from studentname", conn);      conn.Open();      SqlDataReader rdr = cmd.ExecuteReader();      string makestr = "";      for (int k = 0; k < rdr.FieldCount; k++) //获取字段名称      {        makestr += rdr.GetName(k) + "/t"; //载入字段名称      }      makestr += Environment.NewLine; //换行      makestr = makestr + "---------------------------------------------" + Environment.NewLine;      while (rdr.Read()) //逐行读取每一笔记录      {        makestr = makestr + rdr.GetValue(0) + " /t" + rdr.GetValue(1).ToString() + "/t";        makestr = makestr + Environment.NewLine;      }      txtother.Text = makestr;      rdr.Close(); //关闭      conn.Close();

以上所有方法运行结果均如下：