表单未将POST数据传递给控制器

Question

I am passing in a reference to a file, and a string value cardid . For some reason when I return the result the cardid value is null. However when I view the page the <h3> header contains the string I expected. What am I doing wrong?

HTML view

<h3>@Model.CV.Id</h3>

@using (Html.BeginForm("UploadFile", "Tickets", FormMethod.Post, new { cardid=@Model.CV.Id, enctype = "multipart/form-data"}))
{
    <input type="file" name="file" />
    <input type="submit" value="Upload Attachment" />
}

Controller

public async Task<IActionResult> UploadFile(string cardid,IFormFile file)
{
    ......
    string res="yay";
    return Ok(new {cardid=cardid,res=res });
}

Answer 1

You should include cardid in your form. You are simply creating an attribute on <form> , which does nothing.

<h3>@Model.CV.Id</h3>

@using (Html.BeginForm("UploadFile", "Tickets", FormMethod.Post, new { enctype = "multipart/form-data"}))
{
    <input type="hidden" name="cardid" value="@(Model.CV.Id)" />
    <input type="file" name="file" />
    <input type="submit" value="Upload Attachment" />
}

You could also include `cardid in the action:

Html.BeginForm("UploadFile?cardid=" + Model.CV.Id, "Tickets", FormMethod.Post...)