如何在Visual Studio 2012的（数据库）表中手动存储图像并在ASP.NET MVC中使用jquery ajax进行检索

Question

我的数据库表

首先，我尝试存储数据类型为image / varbinary的图像，但出现错误：

“无效值此单元格中更改的值未被识别为有效。.NetFramework数据类型：Byte []错误消息：您不能使用结果窗格将此字段数据设置为NULL以外的值。数据类型或按ESC取消更改”。

如何将图像手动存储在数据库表中，并通过jquery ajax方法撤消它们。

Answer 1

在C＃按钮中使用随数据源一起提交

   if (FileUpload1.PostedFile != null && FileUpload1.PostedFile.FileName != null)
            {
            byte[] img = new byte[Request.Files[0].ContentLength];
            Request.Files[0].InputStream.Read(img, 0, Request.Files[0].ContentLength);
            datasource.Photo = img; --here you can save file to Database
            }

用于从dbserver检索图像的方法如下

img.ImageUrl = "data:image/jpg;base64," + Convert.ToBase64String(Upprofile.Photo);

Answer 2

您是否尝试过其他方式存储图像？
如果您想要我的两美分，我从未使用过这种在数据库中存储图像的方法，最好将图像保存在主机上并将其url保存在数据库中。 您只需要url即可在浏览器中显示图片...！

Answer 3

我不确定这是否适用于VS2012，但是您可以尝试在MVC项目中使用的这种方法：

public action UploadFile(HttpPostedFileBase file) //this is how you get the file that was submited from your form
{
    //so now that I have the file, i need to save it somewhere
    //let's see if we have a folder for that, if not let's create it

    if(!Directory.Exists(Server.MapPath("~/The path from the root of the app to the uploaded files folder/")))
    {
        Directory.CreateDirectory(Server.MapPath("~/The path from the root of the app to the uploaded files folder/"));
    } //the ~ symbol is part of the code, it returns the physical path to the root of the application
    var storage = Server.MapPath("~/The path from the root of the app to the uploaded files folder/");

    //now we need a name, we can generate one as a GUID for example, or we can get it's own.

    var fileName = file.FileName.Substring(file.FileName.LastIndexOf("\"), file.Name.Length + 1);

    //Now you might have to play a bit with the substring arguments, I'm not sure i wrote that right, 
    //it might not need the +1 part, or it might need it on the LastIndexOf as well, 
    //anyway, now we have the name and the folder where to save our file, let's do that:

    path = String.Format("{0}\{1}", storage, filename);
    try
    {
        file.SaveAs(path); //Now the file is on the server, 
        //just save this path and whatever else you need in the database so you can
        //grab it later.
    } 
    catch 
    {
        //do your exception handling here
    }

    Saving to database here...
}

为了抓取它，您只需像其他对象一样从数据库中获取该对象，如下所示：

假设您正在控制器中做所有不应该做的事情，

public Action GetFile(int id)
{
    using(context = new YourDbContext())
    {
        var file = context.Files.FirstOrDefault(p => p.Id == id);
    }
    return View(file);
}

并以html格式显示src的路径，如下所示：

<img src="@Model.path" /> //Considering that in your controller you will `return View(file);` 
//So your file object is the model.

还有一件事，我不确定在路径中是否需要\\或/，我总是第一次出错，因此请在第一次运行时对其进行调试，如果您的路径看起来像Folder1Folder2Folder3File则意味着您需要更改它： ）。

希望这对您有帮助，祝您好运。

PS，也许会有更好的方法来做到这一点，但这就是我正在做的事情，它对我来说工作正常。

Answer 4

在服务器上，将图像转换为base64字符串并保存到数据库。

using (Image image = Image.FromFile(Path))
{                 
    using (MemoryStream m = new MemoryStream())
    {
        image.Save(m, image.RawFormat);
        byte[] imageBytes = m.ToArray();

        // Convert byte[] to Base64 String
        string base64String = Convert.ToBase64String(imageBytes);
        return base64String;
    }                  
}

在客户端旁边，将base64字符串放入Image对象

var image = new Image();
image.src = 'data:image/png;base64,your base64 string';
document.body.appendChild(image);

我认为将映像存储在磁盘上更好。