List<Class> list = new List<Class>(); if (dr.Read()) { Class c = new Class(); c.ClassId1 = Convert.ToString(dr["ClassId"]); c.ClassName1 = Convert.ToString(dr["ClassName"]); list.Add(c); } 然后我在前台messageBox.show(list.count.tostring())为1 说明 list里只发放入了一个class对象啊呀怎么办啊
if (dr.Read())=>while(dr.Read())
List<Class> list = new List<Class>(); while(dr.Read()) { Class c = new Class(); c.ClassId1 = Convert.ToString(dr["ClassId"]); c.ClassName1 = Convert.ToString(dr["ClassName"]); list.Add(c); } int count=list.Count();调试啊, 哪里不对
试了,不对 count等于1啊,可是有好多班级啊,没有加上
private static void ReadOrderData(string connectionString) { string queryString = "SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection = new SqlConnection(connectionString)) { SqlCommand command = new SqlCommand(queryString, connection); connection.Open(); SqlDataReader reader = command.ExecuteReader(); // Call Read before accessing data. while (reader.Read()) { Console.WriteLine(String.Format("{0}, {1}", reader[0], reader[1])); } // Call Close when done reading. reader.Close(); } }
list<Class> list=new list<Class>();
//查询返回dr
while(dr.read())
{
Class c=new Class();
c.id=xxx;
c.name=ooo;
list.add(c);
}
随便学学linq~ 以后干查询list的事情就方便很多
if (dr.Read())
{
Class c = new Class();
c.ClassId1 = Convert.ToString(dr["ClassId"]);
c.ClassName1 = Convert.ToString(dr["ClassName"]);
list.Add(c);
}
然后我在前台messageBox.show(list.count.tostring())为1
说明 list里只发放入了一个class对象啊呀怎么办啊
while(dr.Read())
{
Class c = new Class();
c.ClassId1 = Convert.ToString(dr["ClassId"]);
c.ClassName1 = Convert.ToString(dr["ClassName"]);
list.Add(c);
}
int count=list.Count();调试啊,
哪里不对
count等于1啊,可是有好多班级啊,没有加上
private static void ReadOrderData(string connectionString)
{
string queryString =
"SELECT OrderID, CustomerID FROM dbo.Orders;"; using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlCommand command =
new SqlCommand(queryString, connection);
connection.Open(); SqlDataReader reader = command.ExecuteReader(); // Call Read before accessing data.
while (reader.Read())
{
Console.WriteLine(String.Format("{0}, {1}",
reader[0], reader[1]));
} // Call Close when done reading.
reader.Close();
}
}