1. Description
I want to open the "Create" page, fill in the invoice header data, fill in the invoice dynamic line data and save everything in one submission.
(* updated code) I managed to solve the RowList error which did not allow me to add multiple rows:
How to use AddRange to insert multiple rows in an ASP.NET Core Razor page
Now I get the error
1.1 Error
ArgumentNullException: Value cannot be null. (parameter "source")
System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument parameter)
ArgumentNullException: Value cannot be null. (parameter "source")
System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument) System.Linq.Enumerable.Count<TSource>(IEnumerable<TSource> source) EPIDENT5.Pages.Magazina.Pages_Magazina_Create.<ExecuteAsync>b__28_0() in Create.cshtml
...
@for (int i = 0; i < Model.RowList.Count(); i++)
Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperExecutionContext.GetChildContentAsync(bool useCachedResult, HtmlEncoder encoder) Microsoft.AspNetCore.Mvc.TagHelpers.RenderAtEndOfFormTagHelper.ProcessAsync(TagHelperContext context, TagHelperOutput output) Microsoft.AspNetCore.Razor.Runtime.TagHelpers.TagHelperRunner.g__Awaited|0_0(task task, TagHelperExecutionContextexecutionContext, int i, int count) EPIDENT5.Pages.Magazina.Pages_Magazina_Create.ExecuteAsync()
in Create.cshtmlViewData["Title"] = "Create";
I know I'm missing something, but don't understand what the problem is.
2. Question
How do i do this?
<强>3. Front-end code:
<form method="post">
<div asp-validation-summary="ModelOnly" class="text-danger"></div>
// This is the header table
<table class="table table-striped border-0"
style="width: 100%; text-align: left;">
<thead class="border-0">
<tr class="border-0">
<td class="border-0" style="min-width:100%;">
<div class="border border-secondary p-4">
<div class="row ">
<div style="float:left;width:50%;">
<div class="form-group m-1">
<label asp-for="InvHeader.Cli" class="control-label" style="font-size:80%;">Client</label>
<input asp-for="InvHeader.Cli" class="form-control" value="clients name" />
</div>
</div>
<div style="float:left;width:25%;">
<div class="form-group m-1">
<input asp-for="InvHeader.InvDate" class="form-control" type="date" value="@(DateTime.UtcNow.Date.ToString("yyyy-MM-dd"))" />
<span asp-validation-for="InvHeader.InvDate" class="text-danger"></span>
</div>
</div>
<div style="float:left;width:25%;">
<div class="form-group m-1">
<input asp-for="InvHeader.InvNr" class="form-control" value="33" />
<span asp-validation-for="InvHeader.InvNr" class="text-danger"></span>
</div>
</div>
</div>
</div>
</td>
</tr>
</thead>
</table>
//This is the dynamic rows table
<table id="table1" border="0">
<tr style="font-size:80%;">
<th style="width:50%;">Product</th>
<th style="width:5%;">qty</th>
<th style="width:5%;">price</th>
</tr>
foreach (var item in Model.PL)
{
<tr class="border-bottom">
<td>
<select id="Products" asp-for="@Model.PL[@i].ProdId" class="form-control" type="text" name="data[@i][ProdId]" style="width:100%;" >
@foreach (var item in Model.PL)
{
<option value="@item.ProdId"
qty="@qty"
price="@Convert.ToInt32(item.price)">@item.name, @Convert.ToInt32(item.price)</option>
}
</select>
</td>
<td><input asp-for="@Model.MR[@i].qty" class="form-control" type="text" name="qty[@i]" style="width:100%;" /></td>
<td><input asp-for="@Model.MR[@i].price" class="form-control" type="text" name="price[@i]" style="width:100%;" /></td>
</tr>
</table>
</form>
4.Backend code
//Data binding part
[BindProperty]
public InvHeader InvHeader { get; set; } = default!;
public IList<InvRow> RowList { get; set; }
//onget method, where row count id red
public IActionResult OnGetAsync()
{
var rr = new List<InvRow>()
{
new InvRow() { Name = "Apple", Qty = 5, Price = 100 },
new InvRow() { Name = "Peach", Qty = 3, Price = 500 },
new InvRow() { Name = "Ananas", Qty = 1, Price = 1100 },
};
RowList = rr;
return Page();
}
//Onpost method
public async Task<IActionResult> OnPostAsync(IList<InvRow> RowList)
{
if (!ModelState.IsValid)
{
return Page();
}
_context.InvHeaders.Add(InvHeader);
await _context.InvRows.AddRangeAsync(RowList);
await _context.SaveChangesAsync();
return RedirectToPage("./Index");
} 
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
Model binding binds properties through the name attribute. The correct name property matching the parameter should look like:
addrows[index].propertyName.Not sure what the
PLis in the page, but it seems that only theqtyandpriceinputs are related to theInvRows model. You need to change both input names as follows:If the select element is also related to the
InvRowsmodel, just change the select name, for example:addrows[@i].ProdId. Anyway, the name depends on your model.Additionally, your page contains a duplicate foreach with the same name, which is incorrect. The hypothesis should be:
Full working demo you can follow:
model
public class InvHeaders { public int CliId { get; set; } public DateTime InvDate { get; set; } public string InvNr { get; set; } } public class InvRows { public int qty { get; set; } public int price { get; set; } } public class Product { public int ProdId { get; set; } public string name { get; set; } public int price { get; set; } }page
Page model
public class IndexModel : PageModel { [BindProperty] public InvHeaders InvHeader { get; set; } = default!; [BindProperty] public InvRows InvRow { get; set; } = default!; public IList MR { get; set; } = default!;
public List PL { get; set; }
public void OnGet()
{
//hard-coded the value is just for easy testing
PL = new List()
{
new Product(){ProdId=1,name="aa",price=12},
new Product(){ProdId=2,name="bb",price=16},
new Product(){ProdId=3,name="cc",price=21}
};
}
public void OnPost(List addrows)
{
//do your stuff....
}
} Please note that the default
optionelement below does not have aqtyorpriceattribute, not sure what you want to do, but I need to remind you that this Doesn't make any sense for model binding.