求教啊,C#一直提示"未将对象引用设置到对象的实例",怎么回事啊?
这是错误截图
下面是代码
public List<Customer> GetALL()
{
List<Customer> customers = new List<Customer>();
customers=SqlHelper.ExcuteReader("select * from T_Customer");//就是在这里抛出异常的,可是SqlHelper是个静态类啊
return customers;
}
public static List<Customer> ExcuteReader(string str, params SqlParameter[] para)
{
using (SqlConnection sql = new SqlConnection(connection))
{
sql.Open();
using (SqlCommand com = sql.CreateCommand())
{
com.CommandText = str;
com.Parameters.AddRange(para);
using(SqlDataReader reader=com.ExecuteReader())
{
if (reader==null)
{
return null;
}
List<Customer> customers=new List<Customer>();
while (reader.Read())
{
Customer cus = new Customer();
cus.id = (long)reader["id"];
cus.name = (string)reader["name"];
cus.phonenummer = (string)reader["phonenummer"];
cus.address = (string)reader["address"];
cus.level = (int)reader["level"];
cus.birthday = (DateTime)reader["birthday"];
customers.Add(cus);
}
return customers;
}
}
}
}
SQL
[解决办法]
private static string connection = ConfigurationManager.ConnectionStrings["lianjie"].ConnectionString;
你看一下配置文件中有没有这个项，或者你直接改成
private static string connection = "你的连接字符串"
看一下，我估计应该是这里的问题
