Home Backend Development C#.Net Tutorial Flexibly master the use of GridView in Asp.net MVC

Flexibly master the use of GridView in Asp.net MVC

Dec 24, 2016 pm 01:41 PM

This tutorial shares the usage method and specific implementation code of the GridView control for your reference. The specific content is as follows

The entity class under the Models file:

public class Customer
{
public int Id { get; set; }
public string CompanyName { get; set; }
public string ContactTitle { get; set; }
public string Address { get; set; }
public string City { get; set; } 
public string Country { get; set; }
public string Phone { get; set; }
public DateTime Founded { get; set; }
}
Copy after login

​​​​​​​

public class CustomersViewModel
 
{
public IQueryable<Customer> Customers { get; set; }
 
public PagingInfo PagingInfo { get; set; }
 
public string JsonPagingInfo { get; set; }
}
Copy after login

public static class ExpresssionBuilder
{
private static readonly MethodInfo containsMethod = typeof(string).GetMethod("Contains");
private static readonly MethodInfo startsWithMethod = typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) });
private static readonly MethodInfo endsWithMethod = typeof(string).GetMethod("EndsWith", new Type[] { typeof(string) });
 
 
public static Expression<Func<T,bool>> GetExpression<T>(IList<FilterObject> filters)
{
 if (filters.Count == 0)
 return null;
 
 ParameterExpression param = Expression.Parameter(typeof(T), "t");
 Expression exp = null;
 
 if (filters.Count == 1)
 exp = GetExpression<T>(param, filters[0]);
 else if (filters.Count == 2)
 exp = GetExpression<T>(param, filters[0], filters[1]);
 else
 {
 while (filters.Count > 0)
 {
  var f1 = filters[0];
  var f2 = filters[1];
 
  if (exp == null)
  exp = GetExpression<T>(param, filters[0], filters[1]);
  else
  exp = Expression.AndAlso(exp, GetExpression<T>(param, filters[0], filters[1]));
 
  filters.Remove(f1);
  filters.Remove(f2);
 
  if (filters.Count == 1)
  {
  exp = Expression.AndAlso(exp, GetExpression<T>(param, filters[0]));
  filters.RemoveAt(0);
  }
 }
 }
 
 return Expression.Lambda<Func<T, bool>>(exp, param);
}
 
private static Expression GetExpression<T>(ParameterExpression param, FilterObject filter)
{
 MemberExpression member = Expression.Property(param, filter.Column);
 //ConstantExpression constant = Expression.Constant(filter.Value);
 
 //新的逻辑来处理可空Decimal和DateTime值
 UnaryExpression constant = null;
 if (member.Type == typeof(Decimal?))
 {
 constant = Expression.Convert(Expression.Constant(Decimal.Parse(filter.Value)) , member.Type);
 }
 else if (member.Type == typeof(DateTime?))
 {
 constant = Expression.Convert(Expression.Constant(DateTime.Parse(filter.Value)), member.Type);
 }
 else
 {
 constant = Expression.Convert(Expression.Constant(filter.Value), member.Type);
 }
 
 
 switch (filter.Operator)
 {
 case FilterOperator.Equals:
  return Expression.Equal(member, constant);
 
 case FilterOperator.GreaterThan:
  return Expression.GreaterThan(member, constant);
 
 case FilterOperator.GreaterThanOrEqual:
  return Expression.GreaterThanOrEqual(member, constant);
 
 case FilterOperator.LessThan:
  return Expression.LessThan(member, constant);
 
 case FilterOperator.LessThanOrEqual:
  return Expression.LessThanOrEqual(member, constant);
 
 case FilterOperator.Contains:
  return Expression.Call(member, containsMethod, constant);
 
 case FilterOperator.StartsWith:
  return Expression.Call(member, startsWithMethod, constant);
 
 case FilterOperator.EndsWith:
  return Expression.Call(member, endsWithMethod, constant);
 
 case FilterOperator.NotEqual:
  return Expression.Negate(Expression.Equal(member, constant));
 }
 
 return null;
}
 
private static BinaryExpression GetExpression<T> (ParameterExpression param, FilterObject filter1, FilterObject filter2)
{
 Expression bin1 = GetExpression<T>(param, filter1);
 Expression bin2 = GetExpression<T>(param, filter2);
 
 return Expression.AndAlso(bin1, bin2);
}
}
Copy after login

​​​​​

public class PagingInfo
{
public List<int> PageOptions { get; set; }
 
public bool ShowPageOptions { get; set; }
 
public int TotalItems { get; set; }
public int ItemsPerPage { get; set; }
public int CurrentPage { get; set; }
 
public int TotalPages
{
 get { return (int)Math.Ceiling((decimal)TotalItems / (ItemsPerPage != 0 ? ItemsPerPage : 1)); }
}
 
public SortObject Sort { get; set; }
 
public IList<FilterObject> Filters { get; set; }
 
public string SearchTerm { get; set; }
}
 
public class SortObject
{
public String SortColumn { get; set; }
 
public SortDirection Direction { get; set; }
}
 
public class FilterObject
{
public string Column { get; set; }
 
public string Value { get; set; }
 
public FilterOperator Operator { get; set; }
 
public FilterConjunction Conjunction { get; set; }
}
 
 
/********* ENUMS *************/
public enum SortDirection
{
NotSet,
Ascending,
Descending
}
 
public enum FilterOperator
{
Contains,
GreaterThan,
GreaterThanOrEqual,
LessThan,
LessThanOrEqual,
StartsWith,
EndsWith,
Equals,
NotEqual
}
 
public enum FilterConjunction
{
And,
Or
}
 
public class Extensions
{
public static string GetWhereClause(FilterObject filterObj, Type valueType)
{ 
 string whereClause = "true";
 if (valueType != typeof (DateTime))
 {
 switch (filterObj.Operator)
 {
  case FilterOperator.Contains:
  if (valueType == typeof (string))
   whereClause += string.Format(" {0} {1}.Contains(\"{2}\")", filterObj.Conjunction,
   filterObj.Column, filterObj.Value);
  break;
  case FilterOperator.GreaterThan:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1} > {2}", filterObj.Conjunction, filterObj.Column,
   filterObj.Value);
  break;
  case FilterOperator.GreaterThanOrEqual:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1} >= {2}", filterObj.Conjunction, filterObj.Column,
   filterObj.Value);
  break;
  case FilterOperator.LessThan:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1} < {2}", filterObj.Conjunction, filterObj.Column,
   filterObj.Value);
  break;
  case FilterOperator.LessThanOrEqual:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1} <= {2}", filterObj.Conjunction, filterObj.Column,
   filterObj.Value);
  break;
  case FilterOperator.StartsWith:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1}.StartsWith(\"{2}\")", filterObj.Conjunction,
   filterObj.Column, filterObj.Value);
  break;
  case FilterOperator.EndsWith:
  if (valueType != typeof (string))
   whereClause += string.Format(" {0} {1}.EndsWith(\"{2}\")", filterObj.Conjunction,
   filterObj.Column, filterObj.Value);
  break;
  case FilterOperator.Equals:
 
  whereClause +=
   string.Format(valueType == typeof (string) ? " {0} {1} == \"{2}\"" : " {0} {1} == {2}",
   filterObj.Conjunction, filterObj.Column, filterObj.Value);
  break;
  case FilterOperator.NotEqual:
 
  whereClause +=
   string.Format(valueType == typeof (string) ? " {0} {1} != \"{2}\"" : " {0} {1} != {2}",
   filterObj.Conjunction, filterObj.Column, filterObj.Value);
  break;
  default:
  throw new ArgumentOutOfRangeException();
 }
 }
 else
 {
 DateTime dt;
 DateTime.TryParse(filterObj.Value, out dt);
 
 switch (filterObj.Operator)
 {
  case FilterOperator.Contains:  
  break;
  case FilterOperator.GreaterThan:
 
   whereClause += string.Format(" {0} {1} > DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  case FilterOperator.GreaterThanOrEqual:
 
  whereClause += string.Format(" {0} {1} >= DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  case FilterOperator.LessThan:
 
  whereClause += string.Format(" {0} {1} < DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  case FilterOperator.LessThanOrEqual:
  whereClause += string.Format(" {0} {1} <= DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  case FilterOperator.StartsWith:  
  break;
  case FilterOperator.EndsWith:  
  break;
  case FilterOperator.Equals:
  whereClause += string.Format(" {0} {1} == DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  case FilterOperator.NotEqual:
  whereClause += string.Format(" {0} {1} != DateTime(\"{2}\")", filterObj.Conjunction, filterObj.Column, dt);
  break;
  default:
  throw new ArgumentOutOfRangeException();
 }
 }
 return whereClause;
}
}
Copy after login

MyDbContext.CS code:

public class GridViewModelProvider
{
internal static CustomersViewModel GetCustomersViewModel(MyDbContext db, PagingInfo PagingData)
{
 int TotalItems = 0;
 var model = new CustomersViewModel()
 {
 
 Customers = GetResources(db.Customers.AsQueryable(), PagingData, out TotalItems), 
 PagingInfo = new PagingInfo()
 {
  CurrentPage = PagingData.CurrentPage,
  ItemsPerPage = PagingData.ItemsPerPage,
  PageOptions = new List<int>() { 10, 25, 50, 100 },
  ShowPageOptions = true,
  SearchTerm = PagingData.SearchTerm,
  Sort = PagingData.Sort,
  Filters = PagingData.Filters
 } 
 };
 
 model.PagingInfo.TotalItems = TotalItems;
 model.JsonPagingInfo = Json.Encode(model.PagingInfo);
 
 return model;
}
 
private static IQueryable<Customer> GetResources(IQueryable<Customer> Customers, PagingInfo PagingData, out int TotalItems)
{
 var customers = Customers;
 
 //search
 if (!string.IsNullOrEmpty(PagingData.SearchTerm))
 {
 customers = customers.Where(x => (x.CompanyName.Contains(PagingData.SearchTerm) || x.ContactTitle.Contains(PagingData.SearchTerm)));
 }
 
 //filter
 if (PagingData.Filters != null)
 { 
 foreach (var filterObj in PagingData.Filters)
 {
  switch (filterObj.Column)
  {
  case "City":
   if (filterObj.Value.ToLower() != "all")
   customers = customers.Where(Extensions.GetWhereClause(filterObj, typeof(string)));
   break;
 
  //Add Other Filter Columns Here
  }
 }   
 }
 
 
 TotalItems = customers.Count();
 
 //sort
 customers = customers.OrderBy(x => x.Id);
 if (PagingData.Sort != null)
 {
 switch (PagingData.Sort.Direction)
 {
  case SortDirection.Ascending:
  if (PagingData.Sort.SortColumn == "CompanyName")
  {
   customers = customers.OrderBy(x => x.CompanyName);
  }
  else if (PagingData.Sort.SortColumn == "ContactTitle")
  {
   customers = customers.OrderBy(x => x.ContactTitle);
  }
  break;
  case SortDirection.Descending:
  if (PagingData.Sort.SortColumn == "CompanyName")
  {
   customers = customers.OrderByDescending(x => x.CompanyName);
  }
  else if (PagingData.Sort.SortColumn == "ContactTitle")
  {
   customers = customers.OrderByDescending(x => x.ContactTitle);
  }
  break;
  case SortDirection.NotSet:
  default:
  break;
 }
 }
 customers = customers
 .Skip((PagingData.CurrentPage - 1) * PagingData.ItemsPerPage).Take(PagingData.ItemsPerPage);
 
 return customers;
}
}
Copy after login

HomeController.cs controller:

/// <summary>
/// 启用查询谓词的高效,动态组合。
/// </summary>
public static class PredicateBuilder
{
/// <summary>
/// 创建一个计算结果为true的谓词。
/// </summary>
public static Expression<Func<T, bool>> True<T>() { return param => true; }
 
/// <summary>
/// 创建一个计算结果为false的谓词
/// </summary>
public static Expression<Func<T, bool>> False<T>() { return param => false; }
 
/// <summary>
/// 创建一个从指定的lambda表达式的谓词表达式。
/// </summary>
public static Expression<Func<T, bool>> Create<T>(Expression<Func<T, bool>> predicate) { return predicate; }
 
/// <summary>
/// 结合了第二第一谓词使用逻辑“and”。
/// </summary>
public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> first, Expression<Func<T, bool>> second)
{
 return first.Compose(second, Expression.AndAlso);
}
 
/// <summary>
/// 结合了第二第一谓词使用逻辑“or”。
/// </summary>
public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> first, Expression<Func<T, bool>> second)
{
 return first.Compose(second, Expression.OrElse);
}
 
/// <summary>
///否定谓词
/// </summary>
public static Expression<Func<T, bool>> Not<T>(this Expression<Func<T, bool>> expression)
{
 var negated = Expression.Not(expression.Body);
 return Expression.Lambda<Func<T, bool>>(negated, expression.Parameters);
}
 
/// <summary>
/// 使用指定的合并函数,合并第二和第一表达式
/// </summary>
static Expression<T> Compose<T>(this Expression<T> first, Expression<T> second, Func<Expression, Expression, Expression> merge)
{
 //第二参数映射到第一参数
 var map = first.Parameters
 .Select((f, i) => new { f, s = second.Parameters[i] })
 .ToDictionary(p => p.s, p => p.f);
 
 //第一lambda表达式的参数替换在第二lambda表达式参数
 var secondBody = ParameterRebinder.ReplaceParameters(map, second.Body);
 
 //从第一个表达式创建一个带参数的合并lambda表达式
 return Expression.Lambda<T>(merge(first.Body, secondBody), first.Parameters);
}
 
class ParameterRebinder : ExpressionVisitor
{
 readonly Dictionary<ParameterExpression, ParameterExpression> map;
 
 ParameterRebinder(Dictionary<ParameterExpression, ParameterExpression> map)
 {
 this.map = map ?? new Dictionary<ParameterExpression, ParameterExpression>();
 }
 
 public static Expression ReplaceParameters(Dictionary<ParameterExpression, ParameterExpression> map, Expression exp)
 {
 return new ParameterRebinder(map).Visit(exp);
 }
 
 protected override Expression VisitParameter(ParameterExpression p)
 {
 ParameterExpression replacement;
 
 if (map.TryGetValue(p, out replacement))
 {
  p = replacement;
 }
 
 return base.VisitParameter(p);
 }
}
}
Copy after login

Under the Home view folder:

_CustomersPart ial.cshtml

public class MyDbContext : DbContext
{
public MyDbContext()
 : base("DefaultConnection")
{
 
}
 
public DbSet<Customer> Customers { get; set; }
 
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{ 
 modelBuilder.Entity<Customer>().Property(c => c.CompanyName).HasMaxLength(40);
 modelBuilder.Entity<Customer>().Property(c => c.ContactTitle).HasMaxLength(40);
}
}
Copy after login

_GridViewPartial. cshtml

public class HomeController : Controller
{
public ActionResult Index()
{
 var model = new CustomersViewModel()
 {
 Customers = null,
 PagingInfo = new PagingInfo()
 {
  CurrentPage=1,
  ItemsPerPage= 10,
  PageOptions = new List<int>() { 10,25, 50, 100},
  ShowPageOptions= true,
  TotalItems=1
 }
 };
 return View(model);
}
 
public ActionResult GetCustomers(PagingInfo PagingData)
{
 var db = new MyDbContext();
 var model = GridViewModelProvider.GetCustomersViewModel(db, PagingData); 
 return PartialView("_CustomersPartial", model);
}
 
public ActionResult About()
{
 ViewBag.Message = "您的应用程序描述页面。";
 
 return View();
}
 
public ActionResult Contact()
{
 ViewBag.Message = "您的联系页面。";
 
 return View();
}
}
Copy after login

About.cshtml

@model mesoft.gridview.Models.CustomersViewModel
 
@*在这里写下返回的数据的详细信息*@
<span class="gridview-data-details" style="display:none;">@Html.Raw(Model.JsonPagingInfo)</span>
 
<table class="table table-bordered table-striped">
 <thead>
 <tr class="gridview-list-header">
  <th>
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().Id))
  </th>
  <th class="sortable" data-sort="CompanyName">
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().CompanyName))
  </th>
  <th class="sortable" data-sort="ContactTitle">
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().ContactTitle))
  </th>
  <th>
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().Country))
  </th>
  <th>
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().City))
  </th>
  <th>
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().Address))
  </th>
  <th>
  @(Html.DisplayNameFor(x => x.Customers.FirstOrDefault().Phone))
  </th>
  <th>
  @Html.DisplayNameFor(x=> x.Customers.FirstOrDefault().Founded)
  </th>
 </tr>
 </thead>
 
 <tbody id="CustomersTable" class="gridview-list-items">
 @if (Model.Customers.Any())
 {
  foreach (var c in Model.Customers)
  {
  <tr>
   <td class="value">@c.Id</td>
   <td class="value">@c.CompanyName</td>
   <td class="value">@c.ContactTitle</td>
   <td class="value">@c.Country</td>
   <td class="value">@c.City</td>
   <td class="Description">@c.Address</td>
   <td class="value">@c.Phone</td>
   <td>@c.Founded</td>
  </tr>
  }
 }
 else
 {
  <tr>
  <td colspan="8">
   <div class="alert alert-warning alert-dismissable">
   <button type="button" class="close" data-dismiss="alert" aria-hidden="true">×</button>
   <strong>警告!</strong> 没有客户找到!
   </div>
  </td>
  </tr>
 }
 
 @Html.Raw(ViewBag.Script)
 </tbody>
 
</table>
Copy after login

Contact.cshtml

@model mesoft.gridview.Models.CustomersViewModel
 
<!-- GRIDVIEW-->
<div class="gridview gridview1">
 <!-- GridView Header-->
 <div class="gridview-header">
 <!--GridView的头的左边部分-->
 <div class="col-sm-6">
  <div class="gridview-search">
  <div class="search input-group">
   <input class="form-control" placeholder="Search" type="search">
   <span class="input-group-btn">
   <button class="btn btn-default" type="button">
    <span class="fa fa-search"></span>
    <span class="sr-only">Search</span>
   </button>
   </span>
  </div>
  </div>
 </div>
 
 <!-- GridView的头右边部分-->
 <div class="col-sm-6 text-right">
  <!-- 这里添加任何筛选操作-->
  @{
  string[] cityFilters = {"Istanbul", "Trabzon", "Ankara", "Izmir", "Samsun", "Erzurum"};
  }
 
  根据城市筛选:
  <div class="btn-group">
  <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
   Select City <span class="caret"></span>
  </button>
  <ul class="dropdown-menu filter-parent" role="menu">
   @foreach (var city in cityFilters)
   {
   <li><a href="#" class="filter"
    data-filter-column="City"   
    data-filter-value="@city"
    data-filter-operator="@mesoft.gridview.Models.FilterOperator.Equals"
    data-filter-conjunction="@mesoft.gridview.Models.FilterConjunction.And">@city</a></li>
   }
   <li class="divider"></li>
   <li class="active"><a href="#" class="filter"
     data-filter-column="City"
     data-filter-value="All">All</a></li>
  </ul>
  </div>
 </div>
 </div>
 
 <!-- GridView ViewPort-->
 <div class="gridview-viewport" id="viewport"
  data-getdata-function="@Url.Action("GetCustomers", "Home")"
  data-default-pagesize="10">
 <div class="gridview-canvas" style="min-height:400px;">
  @*Data Will Load Here*@
 </div>
 <div class="loading gridview gridview-loader">
  <img src="~/content/images/loading.gif" />
 </div>
 </div>
 <!-- GridView的分页区域-->
 <div class="gridview-footer">
 @Html.DisplayFor(x => x.PagingInfo, "Pager")
 </div>
</div>
Copy after login

Index.cshtml

@{
 ViewBag.Title = "About";
}
<h2>@ViewBag.Title.</h2>
<h3>@ViewBag.Message</h3>
 
<p>#</p>
Copy after login

Under the Shared folder:

_Layout.cshtml

@{
 ViewBag.Title = "Contact";
}
<h2>@ViewBag.Title.</h2>
<h3>@ViewBag.Message</h3>
 
<address>
 <strong>Support:</strong> <a href="827937686@qq.com">827937686@qq.com</a><br />
</address>
Copy after login

The running result is as shown in the figure:

Asp.net MVC中GridView的使用方法

For more flexibly mastering the use of GridView in Asp.net MVC and related articles, please pay attention to the PHP Chinese website!


Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What is the role of char in C strings What is the role of char in C strings Apr 03, 2025 pm 03:15 PM

In C, the char type is used in strings: 1. Store a single character; 2. Use an array to represent a string and end with a null terminator; 3. Operate through a string operation function; 4. Read or output a string from the keyboard.

How to handle special characters in C language How to handle special characters in C language Apr 03, 2025 pm 03:18 PM

In C language, special characters are processed through escape sequences, such as: \n represents line breaks. \t means tab character. Use escape sequences or character constants to represent special characters, such as char c = '\n'. Note that the backslash needs to be escaped twice. Different platforms and compilers may have different escape sequences, please consult the documentation.

How to use various symbols in C language How to use various symbols in C language Apr 03, 2025 pm 04:48 PM

The usage methods of symbols in C language cover arithmetic, assignment, conditions, logic, bit operators, etc. Arithmetic operators are used for basic mathematical operations, assignment operators are used for assignment and addition, subtraction, multiplication and division assignment, condition operators are used for different operations according to conditions, logical operators are used for logical operations, bit operators are used for bit-level operations, and special constants are used to represent null pointers, end-of-file markers, and non-numeric values.

The difference between char and wchar_t in C language The difference between char and wchar_t in C language Apr 03, 2025 pm 03:09 PM

In C language, the main difference between char and wchar_t is character encoding: char uses ASCII or extends ASCII, wchar_t uses Unicode; char takes up 1-2 bytes, wchar_t takes up 2-4 bytes; char is suitable for English text, wchar_t is suitable for multilingual text; char is widely supported, wchar_t depends on whether the compiler and operating system support Unicode; char is limited in character range, wchar_t has a larger character range, and special functions are used for arithmetic operations.

The difference between multithreading and asynchronous c# The difference between multithreading and asynchronous c# Apr 03, 2025 pm 02:57 PM

The difference between multithreading and asynchronous is that multithreading executes multiple threads at the same time, while asynchronously performs operations without blocking the current thread. Multithreading is used for compute-intensive tasks, while asynchronously is used for user interaction. The advantage of multi-threading is to improve computing performance, while the advantage of asynchronous is to not block UI threads. Choosing multithreading or asynchronous depends on the nature of the task: Computation-intensive tasks use multithreading, tasks that interact with external resources and need to keep UI responsiveness use asynchronous.

How to convert char in C language How to convert char in C language Apr 03, 2025 pm 03:21 PM

In C language, char type conversion can be directly converted to another type by: casting: using casting characters. Automatic type conversion: When one type of data can accommodate another type of value, the compiler automatically converts it.

What is the function of C language sum? What is the function of C language sum? Apr 03, 2025 pm 02:21 PM

There is no built-in sum function in C language, so it needs to be written by yourself. Sum can be achieved by traversing the array and accumulating elements: Loop version: Sum is calculated using for loop and array length. Pointer version: Use pointers to point to array elements, and efficient summing is achieved through self-increment pointers. Dynamically allocate array version: Dynamically allocate arrays and manage memory yourself, ensuring that allocated memory is freed to prevent memory leaks.

How to use char array in C language How to use char array in C language Apr 03, 2025 pm 03:24 PM

The char array stores character sequences in C language and is declared as char array_name[size]. The access element is passed through the subscript operator, and the element ends with the null terminator '\0', which represents the end point of the string. The C language provides a variety of string manipulation functions, such as strlen(), strcpy(), strcat() and strcmp().

See all articles