這段代碼,運(yùn)行到WHILE時,會提示閱讀器關(guān)閉,無法read。為什么閱讀器會關(guān)閉呢?求解釋
public List<StudentClass> GetAllClasses()
{
String Sql = "select ClassID,ClassName from StudentClass ";
SqlDataReader objDataReader = SQLHelper.GetReader(Sql);
List<StudentClass> list = new List<StudentClass>();
while (objDataReader.Read())--------就是這一步
{
list.Add(new StudentClass
{
ClassID = Convert.ToInt32(objDataReader["ClassID"]),
ClassName = Convert.ToString(objDataReader["ClassName"])
});
}
objDataReader.Close();
return list;
}