C#中怎样逐行从数据库中读取数据？

select top 1 * from table where id>当前ID

1//DataReader的详细用法
  2   cmd.CommandText = "GetInfo";
  3  cmd.CommandType = CommandType.StoredProcedure;
  4  SqlParameter param = cmd.Parameters.Add("@Fid",16);
  5  param = cmd.Parameters.Add("@Fname",SqlDbType.VarChar,8);
  6  param.Direction = ParameterDirection.Output;
  7  param = cmd.Parameters.Add("@Fphone",SqlDbType.VarChar,8);
  8  param.Direction = ParameterDirection.Output;
  9  conn.Open();
10  cmd.ExecuteNonQuery();
11  string Fname = cmd.Parameters["@Fname"].Value.ToString();
12  string Fphone = cmd.Parameters["@Fphone"].Value.ToString();
13  Console.WriteLine(Fname + "  " + Fphone);
14  conn.Close();
15  showSplit();
16 }
17
18 //**************************************
19 //*演示读取多个无关记录集
20 //**************************************
21 public void multiResult()
22 {
23  SqlCommand cmd;
24  cmd = conn.CreateCommand();
25  string sqla = "select Fname from friend";
26  string sqlb = "select Fphone from friend";
27  cmd.CommandText = sqla + ";" + sqlb;
28  conn.Open();
29  SqlDataReader reader= cmd.ExecuteReader();
30  int i = 1;
31  do
32  {
33   Console.WriteLine("第" + i.ToString() + "个记录集内容如下：\n");
34   while(reader.Read())
35   {
36    Console.WriteLine(reader[0].ToString() + "\t");
37   }
38   i++;
39  }while(reader.NextResult()); //NextResult()移动到下一个记录集
40  reader.Close();
41  conn.Close();
42  showSplit();
43 }
44
45 //**************************************
46 //*使用DataReader获得数据库模式信息
47 //**************************************
48 public void getSchema()
49 {
50  SqlCommand cmd;
51  cmd = conn.CreateCommand();
52  string sql = "select Fid,Fname,Fphone from friend";
53     cmd.CommandText = sql;
54     conn.Open();
55     SqlDataReader reader = cmd.ExecuteReader();
56     DataTable SchemaTable = reader.GetSchemaTable();
57
58     DataRowCollection SchemaColumns = SchemaTable.Rows;
59     DataColumnCollection SchemaProps = SchemaTable.Columns;
60     foreach(DataRow SchemaColumn in SchemaColumns)
61     {
62      foreach(DataColumn SchemaColumnProp in SchemaProps)
63      {
64       Console.WriteLine(SchemaColumnProp.ColumnName + "=" + SchemaColumn[SchemaColumnProp.ColumnName].ToString());
65      }
66     }
67     reader.Close();
68     conn.Close();
69     showSplit();
70 }
71
72 //**************************************
73 //*从数据库读取二进制数据的代码段
74 //*该代码段只是读取二进制的片断，不是
75 //*整个程序，所以不能执行，你可以把它
76 //*集成到你的WinForm项目里面。
77 //**************************************
78 public void getBinary()
79 {
80  /**//*
81  System.IO.MemoryStream stream = new System.IO.MemoryStream();
82  System.IO.BinaryWriter writer = new System.IO.BinaryWriter(stream);
83  int BufferSize = 1024;
84  byte[] Buffer = new Byte[BufferSize];
85  long Offset = 0;
86  long BytesRead = 0;
87  do
88  {
89   BytesRead = reader.GetBytes(2,Offset,Buffer,0,BufferSize);
90   writer.Writer(Buffer,0,(int)BytesRead);
91   writer.Flush();
92   Offset += BytesRead;
93  }
94  while(BytesRead == BufferSize);
95  */
96 }
97
98 //添加输出分隔
99 private void showSplit()
100 {
101  Console.WriteLine("\n********************************************************************\n");
102 }
103
104 public static void Main(string [] args)
105 {
106  SqlReader sqlreader = new SqlReader();
107
108  sqlreader.basicReader();
109
110  sqlreader.hasParamReader();
111
112  sqlreader.hasOledbParamReader();
113
114  sqlreader.outParamShow();
115
116  sqlreader.multiResult();
117
118  sqlreader.getSchema();
119 }
120}

            string str = @"Data Source=PC-11191038\SQLEXPRESS;Initial Catalog=露天矿卡车调度系统;Persist Security Info=True;User ID=sa;pwd=sa";
            SqlConnection conStr = new SqlConnection(str);
            conStr.Open();
            SqlCommand cmd = new SqlCommand("select X,Y from Sheet1$", conStr);
            List<double> pointX = new List<double>();
            List<double> pointY = new List<double>();
            //float i = (float)cmd.ExecuteScalar();
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                double X = (double)dr["X"];
                double Y = (double)dr["Y"];
                pointX.Add(X);
                pointY.Add(Y);
                //DataSet ds = new DataSet();
                //DataTable x = ds.Tables[0];
                //DataTable y = ds.Tables[1];
            }
我现在已经从数据库中读取X,Y的第一行的值了，请教各位大侠应该怎么改一下，可以逐行都读出来！

用循环while(d.read())
{
}参考

foreach (datarow in datareader)

SqlDataReader reader=command.ExecuteReader();
while(reader.read())
{
每循环一次读一条
}

while(reader.NextResult()) //NextResult()移动到下一个记录集
做個循環就行了

            while (dr.Read())
            {
                double X = (double)dr["X"];
                double Y = (double)dr["Y"];
                pointX.Add(X);
                pointY.Add(Y);
                //DataSet ds = new DataSet();
                //DataTable x = ds.Tables[0];
                //DataTable y = ds.Tables[1];
            }
while就是循环,数据都放到pointX,pointY中了,你可以设置断点调试,查看下pointX,pointY中的值.

调试易

C#中怎样逐行从数据库中读取数据？

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