小编lau*_*ura的帖子

I want to hide the ID column in the QtableView and i can't do that on my implementation. Can anyone help me?

void MainWindow::on_actionClear_Search_triggered()
{
model = new QStandardItemModel(cars.size(),6,this);
//create header
createHeader(model);
//set data to the table view
populate(cars);

ui->tableView->setColumnHidden(6,true);
ui->tableView->setModel(model);


}

void MainWindow::createHeader(QStandardItemModel *model){


model->setHorizontalHeaderItem(0,new QStandardItem("Car"));
model->setHorizontalHeaderItem(1, new QStandardItem("Type"));
model->setHorizontalHeaderItem(2, new QStandardItem("Mileage"));
model->setHorizontalHeaderItem(3, new QStandardItem("Year"));
model->setHorizontalHeaderItem(4, new QStandardItem("Is registered"));
model->setHorizontalHeaderItem(5, new QStandardItem("ID"));
}

void MainWindow::populate(const QList<Vehicle> &vehicles)
{
int j = 0;
QList<Vehicle>::ConstIterator iter;
for( iter= vehicles.begin(); iter != …

有没有办法从表视图中获取选定行的数据？我用过 QModelIndexList ids = ui->tableView->selectionModel()->selectedRows();,它返回所选行的索引列表.我不需要索引.我需要来自所选行的每个单元格的数据.

我有QVector cars,我想根据汽车的注册号进行过滤.我想创建一个新的过滤矢量.我认为这没关系,因为我正在迭代2个向量,从第一个向量复制到第二个向量.我这样做了吗？

void MainWindow::on_actionBy_registration_number_triggered()
{
    myDialog = new MyDialog(this);
    myDialog->exec();

    QString toSearchString = myDialog->getRegistrationNumber();
    QVector<Vehicle> founded;
    QVectorIterator<Vehicle> iterator(cars);
    while(iterator.hasNext()){
        Vehicle car = iterator.next();
        QString num = car.getRegistration().getRegistrationNumber();
        if(num.contains(toSearchString,Qt::CaseInsensitive)){
            founded.append(car);
        }
    }
    model = new QStandardItemModel(founded.size(),5,this);

    //create header
    createHeader(model);

    int j = 0; //row
    QVectorIterator<Vehicle> iter(founded);
    while(iter.hasNext()){
        Vehicle output = iter.next();
        //set car
        QString makeAndModel = output.getGeneralData().getMake() + output.getGeneralData().getModel();
        QStandardItem *mAndM = new QStandardItem(QString(makeAndModel));
        model->setItem(j,0,mAndM);

        //set type
        QStandardItem *type = new QStandardItem(QString(output.getGeneralData().getType()));
        model->setItem(j,1,type);

        //set mileage
        QString mileageString = QString::number(output.getGeneralData().getMileage());
        QStandardItem …

我想在单击delete按钮时从表中删除选定的行.

但我找不到有关删除Qt文档中的行的任何内容.有任何想法吗？

这是我的问题的代码,我得到4个错误:

1. student.obj:错误LNK2005:"struct Node*admitedFirstNode"(？admitedFirstNode @@ 3PAUNode @@ A)已在main.obj中定义
2. student.obj:错误LNK2005:已在main.obj中定义的"struct Node*allFirstNode"(？allFirstNode @@ 3PAUNode @@ A)
3. student.obj:错误LNK2005:已在main.obj中定义的"struct Node*rejectedFirstNode"(？rejectedFirstNode @@ 3PAUNode @@ A)
4. pb4_OOP_lab1\Debug\pb4_OOP_lab1.exe:致命错误LNK1169:找到一个或多个多重定义的符号

#include "students.h"                          //main 
int main()                                         
{
for(int i=0;i<NR_STUDENTS;i++)
{
    Student *s1=new Student;
    cout<<"Enter name: ";
    getline(cin,s1->name);
    cout<<"Enter garde: ";
    cin>>s1->grade;
    cin.ignore();
    addStudent(s1);
    delete s1;
}

}
#include "students.h"                           //students.cpp

void AddNodeToList(Node *firstNode, Student *studToAdd)
{
Node *nodeToAdd=new Node;
nodeToAdd->student=studToAdd;
nodeToAdd->next=NULL;

if(firstNode==NULL)
{
    firstNode=nodeToAdd;
}
else
{
    Node *temp;
    temp=firstNode;
    while(temp->next != NULL)
    {
        temp=temp->next;
    }
    temp->next=nodeToAdd;
}
}
void addStudent(Student …

可能重复:
带空括号的默认构造函数

这是我工作的代码,我不明白它在构造函数Package obj2()上发生了什么; 输出时仅显示值4(包obj1(4))和2(包obj3(2))

#include <iostream>
using namespace std;
class Package
{
private:
    int value;
public:
    Package()
    {
        cout<<"constructor #1"<<endl;
        value = 7; cout << value << endl;

    }
    Package(int v)
    {
        cout<<"constructor #2"<<endl;
        value = v; cout << value << endl;

    }
    ~Package()
    {
        cout<<"destructor"<<endl;
        cout << value << endl;
    }
};

int main()
{
    Package obj1(4);
    Package obj2();
    Package obj3(2);

}

首先,我想为可能重复的主题道歉,但我找不到我的问题的答案.

我今天开始使用spring mvc,我的"hello world"应用程序存在一些问题.任何人都可以帮助我使这个程序工作吗？因为我已经遵循了一些指示,我不知道如何解决这个问题.

这是我的项目结构

HelloController类

package com.pluralsight.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;


@Controller
public class HelloController {

       @RequestMapping(value="/greeting.html")
       public String sayHello(Model model){
        model.addAttribute("greeting","Hello world");

        return "hello";
      }    
  }

为hello.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
     <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
     <title>Insert title here</title>
</head>
<body>    
     <h1>${greeting}</h1>
</body>
</html>

的servlet-config.xml中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">

    <mvc:annotation-driven/>
    <context:component-scan base-package="com.pluralsight.controller"/>

    <bean …

我必须计算从点到线的距离（检查它是线还是线段）。我不确定 bool 函数 IsSegment 是否正常工作。我可以有一些建议吗？谢谢你。

double Distance_From_Line_to_Point(int *a, int *b, int *c, bool IsSegment) {
    double distance;
    int dot1;
    int dot2;
    distance = Cross_Product(a, b, c) / Distance(a, b);
    if (IsSegment(a,b,c) == true) {
        dot1 = Dot_Product(a, b, c);
        if (dot1 > 0) {
            return Distance(b, c);
        }
        dot2 = Dot_Product(b, a, c);
        if (dot2 > 0) {
            return Distance(a, c);
        }
    }
    return fabs(distance);
}

bool IsSegment(int *a, int *b, int *c) {
    double angle1;
    double angle2;
    angle1 = …

我知道这个话题已经讨论过,但我真的找不到解决问题的方法.我想用QDomDocument读取XML文件中的数据,我得到这种类型的错误:

main.obj:-1: error: LNK2019: unresolved external symbol “__declspec(dllimport) public: class QDomElement __cdecl QDomNode::toElement(void)const “ (__imp_?toElement@QDomNode@@QEBA?AVQDomElement@@XZ) referenced in function “void __cdecl ListElements(class QDomElement,class QString,class QString)” (?ListElements@@YAXVQDomElement@@VQString@@1@Z)

包括我

#include <QCoreApplication>
#include <QtXml/QtXml>
#include <QDebug>

我还将Qt + = xml添加到.pro文件中

对于我的作业,我必须从输入文件中读取数据并将其存储在双维数组中,然后将此数组传递给另一个函数.这是我到目前为止所尝试的,但我不知道当我在main中调用此函数时它会给出错误:

访问冲突写入位置0x00000000.

我试图动态分配内存,它给出了同样的错误.我做错了什么？

代码的最后更新:

 #include<stdio.h>
 #include<stdlib.h>

int *a[2];
void getData(void)
{
    FILE *fp = fopen("input.txt", "r");
    int number;

    fscanf(fp, "%d", &number);


    for (int i = 0; i < number; i++)
    {
        a[i]=(int*)malloc(number * sizeof (int));
        fscanf(fp, "%d %d", &a[i][0], &a[i][1]);
    }
    fclose(fp);
}


int main()
{   
    getData();
    for(int i=0;i<8;i++)
    {
        printf("%d %d\n",a[i][0],a[i][1]);
    }
}