Question

我正在定义一个工厂来创建接口实现的对象。工厂包括接口标头以及实现的标头。两个类都在同一名称空间中。然而，在编译工厂时，编译器会给出错误C2065（IntelliSense会解决所有问题，如果这对任何事情都有效）

Public Class Database

    Private m_cnADOConnection As New ADODB.Connection
    Private m_rstAddress As New ADODB.Recordset

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        m_cnADOConnection.Open("Provider = Microsoft.Jet.OLEDB.4.0;" & "Data Source= AddressBook.mdb") ' connects and sets path for database
        m_rstAddress.Open("tblContacts", m_cnADOConnection, ADODB.CursorTypeEnum.adOpenDynamic, ADODB.LockTypeEnum.adLockOptimistic)
        ShowCurrentRecord() 'calls a method to fill the record set
        Me.WindowState = FormWindowState.Normal ' opens form in different states


    End Sub



    Private Sub btnSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSearch.Click
        ShowCurrentRecord()
        Dim Search As String
        Dim SearchLoop As Boolean = False ' sets the loop control 
        Search = InputBox("Enter Surname: ", "Search")
        m_rstAddress.MoveFirst() ' set db to start of file

        If IsNumeric(Search) Then
            MessageBox.Show("Invalid Data: Surname must not be numeric", "Invalid Data")
            Exit Sub ' check that valid entry has been made
        End If
        Do While SearchLoop = False
            If m_rstAddress.EOF() Then
                MessageBox.Show("No Matching Records Found !", "Nil Found", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
                SearchLoop = True
            ElseIf Search = CStr(m_rstAddress.Fields("Surname").Value) Then
                ShowCurrentRecord()
                SearchLoop = True
            Else
                m_rstAddress.MoveNext()
            End If

        Loop
    End Sub

    Private Sub ShowCurrentRecord()

        If m_rstAddress.BOF Or m_rstAddress.EOF Then
            txtFirstName.Text = ""
            txtLastName.Text = ""
            txtAddress1.Text = ""
            txtAddress2.Text = ""
            txtAddress3.Text = ""
            txtPostCode.Text = ""
            txtPhone.Text = ""
            txtEmail.Text = ""
            txtNotes.Text = ""
            Exit Sub
        End If


        txtFirstName.Text = CStr(m_rstAddress.Fields("FirstName").Value) ' the following assigns the text box the value from the DB
        txtLastName.Text = CStr(m_rstAddress.Fields("Surname").Value)
        txtAddress1.Text = CStr(m_rstAddress.Fields("Address1").Value)
        txtAddress2.Text = CStr(m_rstAddress.Fields("Address2").Value)
        txtAddress3.Text = CStr(m_rstAddress.Fields("Address3").Value)
        txtPostCode.Text = CStr(m_rstAddress.Fields("Postcode").Value)
        txtPhone.Text = CStr(m_rstAddress.Fields("Phone").Value)
        txtEmail.Text = CStr(m_rstAddress.Fields("Email").Value)
        txtNotes.Text = CStr(m_rstAddress.Fields("Notes").Value)


    End Sub

    Private Sub btnNew_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAddNew.Click


        txtFirstName.Text = ""
        txtLastName.Text = ""
        txtAddress1.Text = ""
        txtAddress2.Text = ""
        txtAddress3.Text = ""
        txtPostCode.Text = ""
        txtPhone.Text = ""
        txtEmail.Text = ""
        txtNotes.Text = ""
        MessageBox.Show("Please enter the details in the boxes then click Save Record", "Instructions")


    End Sub



    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click


        m_rstAddress.AddNew()

        m_rstAddress.Fields("FirstName").Value = txtFirstName.Text
        m_rstAddress.Fields("Surname").Value = txtLastName.Text
        m_rstAddress.Fields("Address1").Value = txtAddress1.Text
        m_rstAddress.Fields("Address2").Value = txtAddress2.Text
        m_rstAddress.Fields("Address3").Value = txtAddress3.Text
        m_rstAddress.Fields("Phone").Value(-lblPhone.Text)


    End Sub

    Private Sub btnUpdate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUpdate.Click

        m_rstAddress.AddNew()

        m_rstAddress.Fields("FirstName").Value = txtFirstName.Text
        m_rstAddress.Fields("Surname").Value = txtLastName.Text
        m_rstAddress.Fields("Address1").Value = txtAddress1.Text
        m_rstAddress.Fields("Address2").Value = txtAddress2.Text
        m_rstAddress.Fields("Address3").Value = txtAddress3.Text
        m_rstAddress.Fields("Postcode").Value = txtPostCode.Text
        m_rstAddress.Fields("Phone").Value = txtPhone.Text
        m_rstAddress.Fields("Email").Value = txtEmail.Text
        m_rstAddress.Fields("Notes").Value = txtNotes.Text
        m_rstAddress.Update()
        ShowCurrentRecord()
        If m_rstAddress.EOF Then
            m_rstAddress.MoveFirst()
            ShowCurrentRecord()
        Else : m_rstAddress.MoveFirst()
            ShowCurrentRecord()
        End If


        m_rstAddress.Update()
        ShowCurrentRecord()
    End Sub

    Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        Me.Close()
    End Sub



    Private Sub btnFirst_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFirst.Click
        If m_rstAddress.BOF Then
            MessageBox.Show("You have reached the begninning of the file.", "BOF")
            m_rstAddress.MoveFirst()
            ShowCurrentRecord()
        Else : m_rstAddress.MoveFirst()
            ShowCurrentRecord()
Elsee:      m_rstAddress.MovePrevious()
            ShowCurrentRecord()
        End If

    End Sub

    Private Sub btnPrevious_Click(sender As System.Object, e As System.EventArgs) Handles btnPrevious.Click
        If m_rstAddress.BOF Then

            MessageBox.Show("You have reached the end of this file.")
            m_rstAddress.MoveFirst()
            ShowCurrentRecord()
        Else : m_rstAddress.MovePrevious()
            ShowCurrentRecord()

        End If
    End Sub


    Private Sub btnLast_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLast.Click
        If m_rstAddress.BOF Then
            m_rstAddress.MoveLast()
            ShowCurrentRecord()
        Else : m_rstAddress.MoveLast()
            ShowCurrentRecord()


        End If
    End Sub



End Class

界面定义了很多功能，在我看来，这些功能对这个问题没有任何作用。所有功能都是纯虚拟的，并在实现中实现。

#pragma once
#include <memory>
#include "IDBConnector.hpp"
class IDBConnectorFactory
{
public:
  virtual ~IDBConnectorFactory() { }
  virtual std::shared_ptr<IDBConnector> createDBConnector() = 0; ///<  Create a new object of an implementation of the IDBConnector interface
};

编译器输出为：

  #pragma once
  #include <string>
  #include "ConfigFormats.hpp"

  class IDBConnector
  {
  public:
    virtual ~IDBConnector(){};
    virtual bool connect() = 0;
    virtual std::string getSchema() = 0;
    ...
   };

英文应该如下：

  error C2065: "IDBConnector": nichtdeklarierter Bezeichner
  error C2923: "std::shared_ptr": "IDBConnector" ist kein gültiges template-Typargument für den _Ty-Parameter.

可能是我弄乱了配置吗？我试图禁用预编译头的使用，但它没有改变编译错误。

我使用doxygen创建了一个依赖图，以查看循环依赖所在的位置：

我通过将EDLBackend.hpp中的东西放到.cpp文件中并在EDLBackend.hpp中声明IDBConnectorFactory和IDBConnector来解决循环问题。然后我做了另一个循环依赖和tada的整个事情，它的工作原理。谢谢你们！

Answer 1

我敢打赌IDBConnector.hpp开始了：

#pragma once
#include <memory>
#include "IDBConnectorFactory.hpp"

扩展它，但包括前几行，我们有：

#pragma once
#include <memory>
    // #pragma once
    // #include <memory>  - skipped
    // #incude "IDBConnector.hpp" - skipped because of #pragma once
    class IDBConnectorFactory
    { ....

因此定义IDBConnectorFactory时未定义IDBConnector。

修复是其中一个标题必须停止包括另一个标题。您可以可能会从IDBConnector.hpp中删除#include“IDBConnectorFactory.hpp”，只需用一行代替：

    class IDConnectorFactory;

（这告诉编译器有类，所以它可以创建引用和指针，但没有细节。）

Answer 2

您可能在头文件中使用多重保护。试试这个：

ENABLE_PREPROCESSING   = NO

编译器似乎没有使用包含

2 个答案: