在另一个 class C# 中创建一个 object？

Question

我正在向 oop 迈出第一步，这需要破坏我的应用程序并将其全部重新设计为 3 层和面向 object。 叹息。 我有一个提交 object，它应该包含一个客户 object（以及一个经纪人和覆盖对象）； 我想将数据库中的一些数据读取器结果存储在每个包含对象的字段中，但是当我尝试使用新的提交 object 调用客户 object 时，我什么也得不到。 VS 无法识别提交包含客户 object。 我显然错过了一些关键点，所以考虑到这一点，想法？ 代码如下。

//This is the Submission class here
public class Submission 
{
    public int SubmissionId {get;set;}
    public int Status { get; set; }
    public string StatusComment { get; set; }


    public class Customer
    {
        //public Customer() { }
        public int CustId { get; set; }
        public string CustName { get; set; }
        public string CustAddress { get; set; }
        public string CustState { get; set; }
        public string CustCity { get; set; }
        public int CustZip { get; set; }
        public int SicNaic { get; set; }

    }

    public object Customer();
}


//These lines throw an error:

无法通过表达式引用类型。 VS 无法识别 TempSubmission.Customer 提交中对客户 object 的调用。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;


/// This query should selects the relevant data for a gridview on the presentation layer and stores in a list. 
/// Don't quite know how to bind it to the gridview yet, but that's a different question. 

public class SubmissionDatabaseService
{
    public List<Submission> GetAllSubmissions()
    {
        string Searchstring = "SELECT Submission.SubmissionId, Customer.CustName, Customer.CustCity, Customer.CustState, Broker.BroName, Broker.BroState, Broker.EntityType, Submission.Coverage, Status.Status FROM Submission INNER JOIN Broker ON Broker.BroId = Submission.BroId INNER JOIN Customer ON Customer.CustId = Submission.CustId INNER JOIN Status ON Status.StatusId = Submission.StatusId";
        string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;        
        SqlConnection conn = new SqlConnection(connectionString);

        SqlDataReader dr = null;

        try
        {
            conn.Open();

            SqlCommand Searchcmd = new SqlCommand(Searchstring, conn);

            dr = Searchcmd.ExecuteReader();
            List <Submission> lstSubmission;
            Submission tempSubmission;
            while (dr.Read())
            {
                tempSubmission = new Submission();
                tempSubmission.SubmissionId = dr.GetInt32(0);
                tempSubmission.Customer.CustName = dr.GetString(1);
                tempSubmission.Customer.CustCity = dr.GetString(2);
                tempSubmission.Customer.CustState = dr.GetString(3);
                tempSubmission.Broker.BroName = dr.GetString(4);
                tempSubmission.Broker.BroState = dr.GetString(5);
                tempSubmission.Broker.EntityType = dr.GetString(6);
                tempSubmission.SubmissionCoverage.Coverage = dr.GetInt32(7);
                tempSubmission.Status = dr.GetInt32(8);

                //Add rest of the fields
                lstSubmission.Add(tempSubmission);
            }
        }

        return lstSubmission;
    }
}

Answer 1

哦..从哪里开始？ 将您的客户 class 放在自己的文件 Customer.cs 中，将您的提交 class 放在自己的文件 Submission.cs 中

然后你可以像这样做一个简单的提交 class ：

public class Submission 
{
        // consider implementing the below as properties to more finely control access
        public int SubmissionId;
        public int Status;
        public string StatusComment;
        public Customer SubmissionCustomer; // <-- this is null until you set it to a Customer object, either in the constructor or externally.

        public Submission() {
          // constructor
        }

}

然后阅读属性和构造函数，并在你认为合适的时候把它们撒进去。 看：

http://msdn.microsoft.com/en-us/library/x9fsa0sw(v=vs.80).aspx

属性具有私有/公共模式。 至于构造函数：

看：

http://msdn.microsoft.com/en-us/library/ace5hbzh.aspx

每当您创建 class 的实例（对象）时，都会调用构造函数。

Answer 2

我认为您想要的是客户 class 位于提交 class 之外，并且提交 class 包含客户实例。

public class Submission
{
    public Submission()
    {
        this.Customer = new Customer();
    }

    public int SubmissionId { get; set; }
    public int Status { get; set; }
    public string StatusComment { get; set; }
    public Customer Customer { get; set; }
}
public class Customer
{
    //public Customer() { }
    public int CustId { get; set; }
    public string CustName { get; set; }
    public string CustAddress { get; set; }
    public string CustState { get; set; }
    public string CustCity { get; set; }
    public int CustZip { get; set; }
    public int SicNaic { get; set; }
}

Answer 3

仅在提交中定义客户 Object 不会使提交包含客户的实例。 对于您想要做的事情，只需将 Customer 带到 Submission 之外，然后在 Submission 中定义一个 Customer 属性。

Answer 4

您正在尝试通过tempSubmission引用实际的Customer类型。 您必须改为引用Customer的实例，该实例将通过属性或类似的东西公开。

Answer 5

问题是您的客户类型不够具体，它被定义为 Object 而不是客户。

为了实现您想要做的事情，在这种情况下，您必须在您的Submission class 中添加一个Customer类型的新成员，您对public object Customer(); 基本上，定义一个名为 object 类型的Customer的方法。

你想要做的是定义一个Customer类型的属性，称为任何东西，例如RelatedCustomer

Public Customer RelatedCustomer{get;set;}