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靈活掌握Asp.net MVC中GridView的使用方法

高洛峰
發布： 2016-12-24 13:41:53
原創
1889 人瀏覽過

本文教學為大家分享了GridView控制的使用方法和具體實作程式碼，供大家參考，具體內容如下

Models檔案下實體類別:

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; }
}
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public class CustomersViewModel
 
{
public IQueryable<Customer> Customers { get; set; }
 
public PagingInfo PagingInfo { get; set; }
 
public string JsonPagingInfo { get; set; }
}
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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);
}
}
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MyDbContext.CS程式碼:

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;
}
}
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HomeController.cscom omersPartial.cshtml

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;
}
}
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_GridViewPartial. cshtml

/// <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);
 }
}
}
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About.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);
}
}
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Shared資料夾下：

_Layout.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();
}
}
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運作結果如圖:

更多靈活掌握Asp.net MVCGridView的使用方法相關文章請注意PHPP網！

相關標籤：
Asp.net MVC GridView
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