Question

我正在迈出第一步，现在我正在重新建立一个练习项目，使其成为n层和oo。我在我的数据层上有一个查询，内部连接三个表并选择SubmissionId = x的行;业务层有一个服务对象，它将行返回到表示层，但是当我点击演示文稿时，我遇到了障碍。我已经确信数据层上的未分配变量只要在表示层上定义就可以了，但我不知道如何正确调用它。思考？代码如下：

数据层 //这属于公共类SubmissionDatabaseService //

  public Submission GetSubmissionsByID()
{


      string viewQuery = "SELECT Submission.SubmissionId, Customer.CustName, Customer.SicNaic, Customer.CustCity, Customer.CustAddress, Customer.CustState, Customer.CustZip, Broker.BroName, Broker.BroCity, Broker.BroAddress, Broker.BroState, Broker.BroZip, Broker.EntityType, Submission.Coverage, Submission.CurrentCoverage, Submission.PrimEx, Submission.Retention, Submission.EffectiveDate, Submission.Commission, Submission.Premium, Submission.Comments FROM Submission INNER JOIN Broker ON Broker.BroId = Submission.BroId INNER JOIN Customer ON Customer.CustId = Submission.CustId WHERE Submission.SubmissionId =" + x;
      string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
      SqlConnection conn = new SqlConnection(connectionString);



      conn.Open();

      SqlCommand viewCmd = new SqlCommand(viewQuery, conn);
      SqlDataReader dr = viewCmd.ExecuteReader();
      Submission tempSubmission = new Submission();

          tempSubmission.SubmissionId1 = dr.GetInt32(0);
          tempSubmission._Cust.CustName1 = dr.GetString(1);
          tempSubmission._Cust.SicNaic1 = dr.GetInt32(2);
          tempSubmission._Cust.CustCity1 = dr.GetString(3);
          tempSubmission._Cust.CustAddress1 = dr.GetString(4);
          tempSubmission._Cust.CustState1 = dr.GetString(5);
          tempSubmission._Cust.CustZip1 = dr.GetInt32(6);
          tempSubmission._Bro.BroName1 = dr.GetString(7);
          tempSubmission._Bro.BroCity1 = dr.GetString(8);
          tempSubmission._Bro.BroAddress1 = dr.GetString(9);
          tempSubmission._Bro.BroState1 = dr.GetString(8);
          tempSubmission._Bro.BroZip1 = dr.GetInt32(11);
          tempSubmission._Bro.Entity1 = dr.GetString(12);
          tempSubmission._SubCov.Coverage1 = dr.GetInt32(13);
          tempSubmission._SubCov.CurrentCoverage1 = dr.GetInt32(14);
          tempSubmission._SubCov.PrimEx1 = dr.GetInt32(15);
          tempSubmission._SubCov.Retention1 = dr.GetInt32(16);
          tempSubmission._SubCov.EffectiveDate1 = dr.GetDateTime(17);
          tempSubmission._SubCov.Commission1 = dr.GetInt32(18);
          tempSubmission._SubCov.Premium1 = dr.GetInt32(19);
          tempSubmission._SubCov.Comment1 = dr.GetString(20);

          return tempSubmission;
}

业务逻辑层

public class SubmissionService

{

public Submission getSubmissionByID()
{
    SubmissionDatabaseService sds = new SubmissionDatabaseService();
    return sds.GetSubmissionsByID();
}

}

演示文稿图层

 protected void Page_Load(object sender, EventArgs e)
{

    string x = Request.QueryString["SubmissionId"];


    Submission sub = SubmissionService.getSubmissionByID(x); //Here is where I throw an overload error

Answer 1

你的getSubmissionByID没有参数，但是你要传递一个参数。您需要将要传递的ID提供给数据库以进行查询。

public Submission getSubmissionByID(string id)
{
    SubmissionDatabaseService sds = new SubmissionDatabaseService();
    return sds.GetSubmissionsByID(id);
}

您还需要让数据访问获取参数，然后在查询中使用该参数。 '+ x'不是最佳做法。您应该使用查询参数。

    public Submission GetSubmissionsByID(string id)
    {
          string viewQuery = @"SELECT Submission.SubmissionId, Customer.CustName, Customer.SicNaic, Customer.CustCity, Customer.CustAddress, Customer.CustState, Customer.CustZip, Broker.BroName, Broker.BroCity, Broker.BroAddress, Broker.BroState, Broker.BroZip, Broker.EntityType, Submission.Coverage, Submission.CurrentCoverage, Submission.PrimEx, Submission.Retention, Submission.EffectiveDate, Submission.Commission, Submission.Premium, Submission.Comments
    FROM Submission
        INNER JOIN Broker ON Broker.BroId = Submission.BroId INNER JOIN Customer ON Customer.CustId = Submission.CustId
    WHERE Submission.SubmissionId = @id";

          string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
          SqlConnection conn = new SqlConnection(connectionString);
    Conn.Open();
    SqlCommand viewCmd = new SqlCommand(viewQuery, conn);
    var parameter = new SqlParameter("@id", SqlDbType.VarChar)
    parameter.Value = id;
    cmd.Parameters.Add(parameter);

    // skip some stuff
   }

Answer 2

SubmissionService.getSubmissionByID()没有参数。所以你不能通过x。像这样在商业层中更改它的签名。

public Submission getSubmissionByID(string x)
{
    SubmissionDatabaseService sds = new SubmissionDatabaseService();
    return sds.GetSubmissionsByID(s);
}

和像这样的数据层

public Submission GetSubmissionsByID(string x)
{


      string viewQuery = "SELECT Submission.SubmissionId, Customer.CustName, Customer.SicNaic, Customer.CustCity, Customer.CustAddress, Customer.CustState, Customer.CustZip, Broker.BroName, Broker.BroCity, Broker.BroAddress, Broker.BroState, Broker.BroZip, Broker.EntityType, Submission.Coverage, Submission.CurrentCoverage, Submission.PrimEx, Submission.Retention, Submission.EffectiveDate, Submission.Commission, Submission.Premium, Submission.Comments FROM Submission INNER JOIN Broker ON Broker.BroId = Submission.BroId INNER JOIN Customer ON Customer.CustId = Submission.CustId WHERE Submission.SubmissionId =" + x;
      ...

Answer 3

您只需要声明数据层方法的参数：

public Submission GetSubmissionsByID()

变为

public Submission GetSubmissionsByID(string x)

但是，这会使您的系统对SQL注入保持开放状态 在尝试编写嵌入在C＃（或其他语言）中的SQL之前，请先阅读参数化的SQL语句

使用select where变量传递一个对象？

3 个答案: