清清楚楚asp.net ( 九 ) : ADO.NET之Command/DataReader

一.Command类

Command类可以执行任何类型的SQL语句。

1.Command对象的主要属性

在使用任何一个Command对象之前，必须完成对Command对象以下三个属性的设置。

(1).CommandType

其值为一枚举。枚举值分别为：Command.Text;Command.StoredProcedure;Command.TableDirect;

Command对象默认的CommandType类型为Command.Text

(2).CommandText

其值为SQL语句或者为存储过程的名字。

(3).Connection

Command初始化的示例：

C#

1 protected void SqlCommondSelect()
2 {
3 string connectionString = ConfigurationManager.ConnectionStrings["MyDemo"].ConnectionString;
4 SqlConnection connection = new SqlConnection(connectionString);
5 SqlCommand cmd2 = new SqlCommand("SelectAllProductions", connection);
6 cmd2.CommandType = CommandType.StoredProcedure;
7 try
8 {
9 connection.Open();
10 SqlDataReader reader = cmd2.ExecuteReader(CommandBehavior.CloseConnection);
11 StringBuilder htmlStr = new StringBuilder();
12 htmlStr.Append("<ul>");
13 while (reader.Read())
14 {
15 htmlStr.Append("<li><b>Production Name : </b>" + reader.GetString(2));
16 htmlStr.Append("<b> Price : </b>" + (decimal)reader["DefaultPrice"] + "</li>");
17 }
18 htmlStr.Append("</ul>");
19 reader.Close();
20 connection.Close();
21 this.litInfo.Text = htmlStr.ToString();
22 }
23 catch (Exception err)
24 {
25 this.lblError.Text = err.Message;
26 }
27 }
28
29 protected int CommandScalar()
30 {
31 string connectionString = ConfigurationManager.ConnectionStrings["MyDemo"].ConnectionString;
32 SqlConnection con = new SqlConnection(connectionString);
33 SqlCommand cmd = new SqlCommand("SELECT COUNT(*) FROM Productions", con);
34 con.Open();
35 int count = (int)cmd.ExecuteScalar();
36 con.Close();
37 return count;
38 }
39
40 protected int CommandNonQuery()
41 {
42 string connectionString = ConfigurationManager.ConnectionStrings["MyDemo"].ConnectionString;
43 SqlConnection con = new SqlConnection(connectionString);
44 SqlCommand cmd = new SqlCommand("UPDATE Productions SET ProductionName=ProductionName WHERE CateGoryID=1", con);
45 con.Open();
46 int count = cmd.ExecuteNonQuery();
47 con.Close();
48 return count;
49 }



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参考资料：Pro ASP.NET 3.5 in C# 2008

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