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大神:C#中ExecuteScalar: Connection

发布时间: 2012-06-16 20:34:32 作者: rapoo

大神求救:C#中ExecuteScalar: Connection 属性尚未初始化的问题
程序功能主要是想从数据库中查询并统计学生总数,再将这个数插入到随机数产生器中,
进行从1-zh的数字产生(其中zh是一个变量)
但是一直说我没初始化,求解啊,同志们,我是菜鸟

con.Open();
String select1 = "select count(*) from student";
SqlCommand cmd2 = new SqlCommand();
cmd2.CommandText = select1;
int zh = 0;
zh = Convert.ToInt32(cmd2.ExecuteScalar()); //强制数据转换

int suijishu = new Random().Next(1, zh);//随机数产生器

[解决办法]

C# code
string queryString ="select count(*) as stuNum from student";string connectionString = "server='(local)';database='mytable';uid='sa';pwd='sa'";   using (SqlConnection connection = new SqlConnection( connectionString))  {  SqlCommand command = new SqlCommand( queryString, connection);       connection.Open();  SqlDataReader reader = command.ExecuteReader();  try  {  while (reader.Read())  {     int zh = 0;    zh = Convert.ToInt32(reader["stuNum"]); //强制数据转换  }  }  finally  {  // Always call Close when done reading.  reader.Close();  } 

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