英文:
Detecting page refresh c#
问题
我使用ASP.NET Core Web应用程序创建了一个文档上传站点，但遇到了一个小错误，我不确定如何修复。
在我的站点上，首先创建一个'file'，如下所示：
然后它会出现在一个列表中，如下所示：
当您点击上传附件时，它会传递上一个表格中的ID，以确保它上传到正确的文件。
上传页面的代码如下，错误在于如果在选择文件之前点击上传，它会刷新页面以显示错误，然后之前传递的ID已丢失，所以myInv最终变为null。
using FarmersPortal.Data;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using File = FarmersPortal.Data.File;
namespace FarmersPortal.Pages.Admin
{
[Authorize(Roles = "Admin")]
public class UploadModel : PageModel
{
private readonly filedbContext _context;
public UploadModel(filedbContext context)
{
_context = context;
}
public int? myID { get; set; }
[BindProperty]
public IFormFile file { get; set; }
[BindProperty]
public int? ID { get; set; }
public void OnGet(int? id)
{
myID = id;
}
[BindProperty]
public File File { get; set; }
public async Task<IActionResult> OnPostAsync()
{
if (file != null)
{
if (file.Length > 0 && file.Length < 300000)
{
var myInv = _context.Files.FirstOrDefault(x => x.Id == ID);
var date = DateTime.Today;
using (var target = new MemoryStream())
{
file.CopyTo(target);
myInv.UploadDate = date;
myInv.Attachment = target.ToArray();
}
if (myInv == null)
{
return NotFound();
}
else
{
File = myInv;
}
_context.Files.Update(myInv);
await _context.SaveChangesAsync();
}
}
if (File.FileType == "Purchase Order")
{
return RedirectToPage("./PurchaseOrders");
}
else if (File.FileType == "Remittance")
{
return RedirectToPage("./Remittance");
}
else if (File.FileType == "Haulage Self Bill")
{
return RedirectToPage("./HaulageSelfBill");
}
else if (File.FileType == "Growers Return")
{
return RedirectToPage("./GrowersReturn");
}
return Page();
}
}
}
我不确定如何解决这个问题，有什么想法？
以上是前端代码。
英文:
I have created a document upload site with asp.net core web app's, and I have encountered a small bug but I'm not sure how to fix it.
On my site, you first create a 'file' like so:
It then appears in a list like so:
And when you press upload attachment, it passes the id from the previous table to ensure it uploads to the correct file.
The code behind the upload page is as below, and the error is if you press upload before choosing a file, it does a page refresh to display an error and then the ID passed through before has been lost, so myInv ends up being null.
using FarmersPortal.Data;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using File = FarmersPortal.Data.File;
namespace FarmersPortal.Pages.Admin
{
[Authorize(Roles ="Admin")]
public class UploadModel : PageModel
{
private readonly filedbContext _context;
public UploadModel(filedbContext context)
{
_context = context;
}
public int? myID { get; set; }
[BindProperty]
public IFormFile file { get; set; }
[BindProperty]
public int? ID { get; set; }
public void OnGet(int? id)
{
myID = id;
}
[BindProperty]
public File File { get; set; }
public async Task<IActionResult> OnPostAsync()
{
if (file != null)
{
if (file.Length > 0 && file.Length < 300000)
{
var myInv = _context.Files.FirstOrDefault(x => x.Id == ID);
var date = DateTime.Today;
using (var target = new MemoryStream())
{
file.CopyTo(target);
myInv.UploadDate = date;
myInv.Attachment = target.ToArray();
}
if (myInv == null)
{
return NotFound();
}
else
{
File = myInv;
}
_context.Files.Update(myInv);
await _context.SaveChangesAsync();
}
}
if (File.FileType == "Purchase Order")
{
return RedirectToPage("./PurchaseOrders");
}
else if (File.FileType == "Remittance")
{
return RedirectToPage("./Remittance");
}
else if (File.FileType == "Haulage Self Bill")
{
return RedirectToPage("./HaulageSelfBill");
}
else if (File.FileType == "Growers Return")
{
return RedirectToPage("./GrowersReturn");
}
return Page();
}
}
}
I am not sure how to work my way around this, any ideas?
@page
@model FarmersPortal.Pages.Admin.UploadModel
@{
}
<h1 style="color:white">Upload File</h1>
<style>
body {
background-image: url("http://10.48.1.215/PORTAL/hero-range-1.jpg");
height: 100%;
background-position: center;
background-repeat: no-repeat;
background-size: cover;
}
</style>
<hr />
<div class="row">
<div class="col-md-4">
<form method="post" enctype="multipart/form-data">
<div class="form-group">
<div class="col-md-10">
<p style="color:white">Upload file</p>
<input type="hidden" asp-for="@Model.ID" value="@Model.myID" />
<input asp-for="file" class="form-control" accept=".pdf" type="file" />
<span asp-validation-for="file" class="text-white"></span>
</div>
</div>
<div class="form-group">
<div class="col-md-10">
<input class="btn btn-success" type="submit" value="Upload" />
</div>
</div>
</form>
</div>
</div>
<div>
<a asp-page="Index">Back to List</a>
</div>
Above is the front end code.
答案1
得分: 1
您可以自定义错误消息
[BindProperty]
[Required(ErrorMessage = "您必须在上传此表单之前选择一个文件")]
public IFormFile file { get; set; }
您还需要将Jquery验证库添加到视图中：
@section Scripts {
@{
await Html.RenderPartialAsync("_ValidationScriptsPartial");
}
}
然后，当用户未选择任何文件并点击上传按钮时，视图将显示错误消息并停止上传表单。
英文:
You can custom the error message
[BindProperty]
[Required(ErrorMessage ="You must select a file before upload this form")]
public IFormFile file { get; set; }
And you also need to add Jquery validation library to your view:
@section Scripts {
@{
await Html.RenderPartialAsync("_ValidationScriptsPartial");
}
}
Then when user don't select any file and click the upload button, View will show error message and stop uploading the form.
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