![](/img/trans.png)
[英]Reusing code from my ASP.NET Core MVC app in console app : how to do database connection
[英]How do I add a sorting feature to my MVC asp.net Core app?
我有一個 MVC 應用程序,用戶可以在其中記錄他們的創建條目並在屏幕上的表格中查看它們。 我想添加一個功能,用戶可以在其中單擊名稱標題和按名稱列排序的表格。 我正在使用這個 docs.Microsoft 教程來幫助我,但我似乎沒有任何進展。 這是我到目前為止所擁有的:
控制器:
public async Task<IActionResult> Index(string sortOrder)
{
ViewData["NameSortParm"] = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
ViewData["DateSortParm"] = sortOrder == "Date" ? "date_desc" : "Date";
var logs = from l in _context.Log
select l;
switch (sortOrder)
{
case "name_desc":
logs = logs.OrderByDescending(l => l.Name);
break;
case "Date":
logs = logs.OrderBy(l => l.Date);
break;
case "date_desc":
logs = logs.OrderByDescending(l => l.Date);
break;
case "relation":
logs = logs.OrderByDescending(l => l.Relation);
break;
case "type":
logs = logs.OrderByDescending(l => l.Type);
break;
default:
logs = logs.OrderBy(l => l.Date);
break;
}
return View(await logs.AsNoTracking().ToListAsync());
}
public async Task OnGetAsync(string parentComment, string searchString)
{
// Use LINQ to get list of dates.
IQueryable<DateTime> dateQuery = from m in _context.Log
// orderby m.Date
select m.Date;
var logs = from l in _context.Log
select l;
if (!String.IsNullOrEmpty(searchString))
{
logs = logs.Where(s => s.Name.Contains(searchString));
}
if (!String.IsNullOrEmpty(parentComment))
{
logs = logs.Where(x => x.Type == parentComment);
}
Dates = new SelectList(await dateQuery.Distinct().ToListAsync());
Log = await logs.ToListAsync();
}
看法
<table class="table">
<thead>
<tr>
<th>
@Html.DisplayNameFor(model => model.Log[0].Date)
</th>
<th>
<a asp-action="Index" asp-route-sortOrder='@ViewData["NameSortParm"]'>
@Html.DisplayNameFor(model => model.Log[0].Name)
</a>
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Relation)
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Type)
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Comment)
</th>
<th></th>
</tr>
</thead>
<tbody>
@foreach (var item in Model.Log)
{
<tr>
<th>
@Html.DisplayFor(modelItem => item.Date)
</th>
<td>
@Html.DisplayFor(modelItem => item.Name)
</td>
<td>
@Html.DisplayFor(modelItem => item.Relation)
</td>
<td>
@Html.DisplayFor(modelItem => item.Type)
</td>
<td>
@Html.DisplayFor(modelItem => item.Comment)
</td>
<td>
<a asp-page="./Edit" asp-route-id="@item.ID">Edit</a> |
<a asp-page="./Details" asp-route-id="@item.ID">Details</a> |
<a asp-page="./Delete" asp-route-id="@item.ID">Delete</a>
</td>
</tr>
}
</tbody>
</table>
如您所見,我為視圖中的Name列設置了它。 當我點擊它時,URL 會發生變化,讓我知道Index()
方法已觸發( https://localhost:5001/HSLogs?action=Index )並且頁面會重新加載。 沒有排序發生。 幾乎沒有任何事情發生。 想法?
陳雪莉的建議奏效了。 謝謝你。
我擺脫了控制器中的Task<T> Index
方法。 我將 switch 語句移至Task OnGetAsync()
方法並更新了語法。
控制器:
public string NameSort { get; set; }
public string DateSort { get; set; }
public async Task OnGetAsync(string sortOrder)
{
NameSort = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
DateSort = sortOrder == "Date" ? "date_desc" : "Date";
IQueryable<Log> logsEntry = from s in _context.Log
select s;
switch (sortOrder)
{
case "name_desc":
logsEntry = logsEntry.OrderByDescending(l => l.Name);
break;
case "Date":
logsEntry = logsEntry.OrderBy(l => l.Date);
break;
case "date_desc":
logsEntry = logsEntry.OrderByDescending(l => l.Date);
break;
default:
logsEntry = logsEntry.OrderBy(l => l.Date);
break;
}
Log = await logsEntry.AsNoTracking().ToListAsync();
}
在視圖中,我為日期列和名稱列使用適當的標簽助手更新了標題鏈接。
看法
<table class="table">
<thead>
<tr>
<th>
<a asp-page="./Index" asp-route-sortOrder="@Model.DateSort">
@Html.DisplayNameFor(model => model.Log[0].Date)
</a>
</th>
<th>
<a asp-page="./Index" asp-route-sortOrder="@Model.NameSort">
@Html.DisplayNameFor(model => model.Log[0].Name)
</a>
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Relation)
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Type)
</th>
<th>
@Html.DisplayNameFor(model => model.Log[0].Comment)
</th>
<th></th>
</tr>
</thead>
...
</table>
在 Asp.net core 5.0 上進行排序的一種簡單且可重用的方法
public async Task<IActionResult> Index(Query query)
{
var models = await _context.model.AsQueryable();
var columnName = new Dictionary<string, Expression<Func<Model, object>>>()
{
["name"] = m => m.name,
["date"] = m => m.date
}
models = query.IsSortByAscending
? models.SortBy(columnName[query.SortBy])
: models.OrderByDescending(columnName[query.SortBy])
}
如果要添加更多列進行排序,只需添加列名作為 Dictionay 中的鍵及其值(以 Lamba 表達式的形式)。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.