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c# - Taking an image and storing as string it from user using .net MVC 5

问题描述

I am a student developer in .Net MVC 5 and I want to insert image from new user to my database. I found a lot of method for byte[] data type but according to my researchs , there is no source for string data type.(Example; Entity Framework 5 Code first adding an image) . What can i do for string column of ImageUrl in my database? Could you help me at this issue ?

My Model :

public class usersModel{
public string userImageUrl{get;set;}
}

My Controller : 

 public class UsersController : Controller
    {
        AgmEntities db = new AgmEntities();

        public ActionResult Create()
        {
            return View("Create", new usersModel());
        }

        [HttpPost]
        public ActionResult Create(usersModel uModel,HttpPostedFileBase file)
        {
            if (!ModelState.IsValid)
            {

                return View("Create");
            }

            var user = new Users();

            if(file !=null && file.ContentLength > 0)
            {
                string fileName = Path.GetFileName(file.FileName);
                string imgPath = Path.Combine(Server.MapPath("~/User_Images/"), fileName);
                file.SaveAs(imgPath);
            }
            user.userImageUrl = "~/User_Images/" + file.FileName;/*Error line*/
            db.Users.Add(user);
            db.SaveChanges();
            return RedirectToAction("Index", "Home");
        }
    }

My cshtml :

@using (Html.BeginForm()) 
{
    @Html.AntiForgeryToken()

        <div class="form-group">
            @Html.LabelFor(model => model.userImageUrl, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                <input type="file" name="ImageFile" />
                @Html.ValidationMessageFor(model => model.userImageUrl, "", new { @class = "text-danger" })
            </div>
        </div>
    }

标签： c#asp.net-mvcrazor

解决方案

您必须在表单中添加新{ enctype="multipart/form-data"}内容才能允许上传文件。

Html.BeginForm(
    null, null, FormMethod.Post, new { enctype="multipart/form-data"})

将cshtml代码更改为：

@using (Html.BeginForm(
    null, null, FormMethod.Post, new { enctype="multipart/form-data"})) 
{
    @Html.AntiForgeryToken()

        <div class="form-group">
            @Html.LabelFor(model => model.userImageUrl, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                <input type="file" name="ImageFile" />
                @Html.ValidationMessageFor(model => model.userImageUrl, "", new { @class = "text-danger" })
            </div>
        </div>
    }

if user.userImageUrl = "~/User_Images/" + file.FileName;/*Error line*/ 并在这种情况下将这行代码移到里面file.FileName可能为空。

 if(file !=null && file.ContentLength > 0)
            {
                string fileName = Path.GetFileName(file.FileName);
                string imgPath = Path.Combine(Server.MapPath("~/User_Images/"), fileName);
                file.SaveAs(imgPath);
                user.userImageUrl = "~/User_Images/" + file.FileName;/*Error line*/
            }

parameter name需要更改与文件类型相同的操作的另一注意事项name of input：

<input type="file" name="ImageFile" /> to <input type="file" name="file" />

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