在 Razor 页面中使用日期时间参数

Question

Essentially I'm trying to build a date picker filter for my List page. I started by using some of the logic found in the search function detailed here: https://docs.microsoft.com/en-us/aspnet/core/data/ef-rp/sort-filter-page?view=aspnetcore-3.1#add-paging

My Get method is structured like so:

public async Task OnGetAsync(string sortOrder, string currentFilter, string searchString, int? pageIndex, string startDate, string endDate)
        {
            if (endDate==null)
            {
                endDate = TimeUtils.DateToString(DateTime.Now);
            }
            if (startDate==null)
            {
                startDate = TimeUtils.DateToString(DateTime.Now.AddDays(-60));
            }
            EndDate = TimeUtils.StringToDate(endDate);
            StartDate = TimeUtils.StringToDate(startDate);
            CurrentSort = sortOrder;
            NameSort = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "Name";
            DateSort = sortOrder == "Date" ? "" : "Date";
            if (searchString != null)
            {
                pageIndex = 1;
            }
            else
            {
                searchString = currentFilter;
            }
            CurrentFilter = searchString;
            IQueryable<Issue> issuesIQ = _context.Issue.Include(o => o.Agent);
            if (!String.IsNullOrEmpty(searchString))
            {
                issuesIQ = issuesIQ.Where(o => o.Agent.ADAccount.Contains(searchString));
            }
            switch (sortOrder)
            {
                case "name_desc":
                    issuesIQ = issuesIQ.OrderByDescending(o => o.Agent.ADAccount);
                    break;
                case "Date":
                    issuesIQ = issuesIQ.OrderBy(o => o.ContactDate);
                    break;
                case "Name":
                    issuesIQ = issuesIQ.OrderBy(o => o.Agent.ADAccount);
                    break;
                default:
                    issuesIQ = issuesIQ.OrderByDescending(o => o.ContactDate);
                    break;
            }
            int pageSize = 50;
            Issues = await PaginatedList<Issue>.CreateAsync(issuesIQ.AsNoTracking(), pageIndex ?? 1, pageSize);
            
            
        }

This sets the date range to the last 60 days when I initially load the page(when no parameters are supplied) and converts them to strings(more on that in a moment), then converts whatever is stored in those strings into the DateTime objects used by the Picker(shown below)

<form asp-page="./Index" method="get">
    <div class="form-actions no-color">
        <p>
            <div class="form-group">
                <label asp-for="StartDate" class="control-label"></label>
                <input asp-for="StartDate" class="form-control"/>
                <span asp-validation-for="StartDate" class="text-danger"></span>
                <label asp-for="EndDate" class="control-label"></label>
                <input asp-for="EndDate" class="form-control"/>
                <span asp-validation-for="EndDate" class="text-danger"></span>
            </div>Find by Agent NT:
            <input type="text" name="SearchString" value="@Model.CurrentFilter" />
            <input type="submit" value="Search" class="btn btn-primary" /> |
            <a asp-page="./Index">Back to full List</a>
        </p>
    </div>
</form>

From there, I modify the next and previous buttons to pass the value of the picker(after converting it back to a string) to the get method when navigating from page to page.

<a asp-page="./Index"
   asp-route-sortOrder="@Model.CurrentSort"
   asp-route-pageIndex="@(Model.Issues.PageIndex - 1)"
   asp-route-currentFilter="@Model.CurrentFilter"
   asp-route-endDate="@TimeUtils.DateToString(Model.EndDate)"
   asp-route-startDate="@TimeUtils.DateToString(Model.StartDate)"
   class="btn btn-primary @prevDisabled">
    Previous
</a>
<a asp-page="./Index"
   asp-route-sortOrder="@Model.CurrentSort"
   asp-route-pageIndex="@(Model.Issues.PageIndex + 1)"
   asp-route-currentFilter="@Model.CurrentFilter"
   asp-route-endDate="@TimeUtils.DateToString(Model.EndDate)"
   asp-route-startDate="@TimeUtils.DateToString(Model.StartDate)"
   class="btn btn-primary @nextDisabled">
    Next
</a>

Now, to explain why I'm using strings for the parameters and where I'm stuck. I noticed when I was initially using DateTimes as the parameters I'd have them default to DateTime.MinValue, which wasn't a huge thing to overcome, but when I would navigate to the next page my URL would have a bunch of gibberish and my picker values would simply read mm/dd/yyyy. I did some reading and found IIS doesn't like to play well with some of the delimiters in DateTime, even with the [DataType(DataType.Date)] annotations I had in play. At this point I read some documentation on DateTime.Parse and DateTime.ToString and made these helper functions in TimeUtils

public static DateTime StringToDate(string datetime)
        {
            DateTime dt = DateTime.Parse(datetime);
            return dt;
        }
        public static string DateToString(DateTime dt)
        {
            return dt.ToString("d");
        }

This should just convert the DateTime to a string like 9/15/2020, but when I try to navigate from page to page I'm getting the following at the end of my URL:

/Issues?pageIndex=3&endDate=9%2F14%2F2020&startDate=7%2F16%2F2020

To boil all this down, am I on the right path here and do I just need to do additional customization on the Parse and ToString functions to eliminate those "/"s from the strings? I'm considering using de culture as an argument in the ToString call to convert it to ".", but not sure if I'll run into similar problems.

Answer 1

Figured it out by continuing down the path I was on, but with a few caveats I'm still scratching my head on. Updated the TimeUtils helper functions as follows:

public static DateTime StringToDate(string datetime)
        {
            DateTime dt = DateTime.ParseExact(datetime,"yyyy-MM-dd",null);
            return dt;
        }
        public static string DateToString(DateTime dt)
        {
            StringBuilder sb = new StringBuilder();
            sb.Append(dt.Year);
            sb.Append("-");
            if (dt.Month < 10)
                sb.Append("0");
            sb.Append(dt.Month);
            sb.Append("-");
            if (dt.Day < 10)
                sb.Append("0");
            sb.Append(dt.Day);
            return sb.ToString();
        }

I initially went the route of "yyyyMMdd" format, but when I tried to do the initial filter(clicking search) I had an error indicating the ParseExact couldn't convert "2020-09-16" to a valid date. I couldn't find anywhere in the OnGet this conversion was occurring and figured something wonky was happening with Append, so I updated the ParseExact to the new format. This worked fine until I went to the next page, which actually followed my DateToString as initially coded(without the "-"s) and failed. I updated the DateToString to include the "-"s and now everything works as intended. My guess is some kind of implicit conversion to "yyyy-MM-dd" was happening on the asp-for selection in the filter? Regardless it works.

What a ride.