ASP.NET Core MVC，从数据库中获取文件，并渲染为图像

问题描述

我将图像数据存储在字段类型为 varbinary(max) 的 SQL 表中，我还存储图像内容类型.

I have image data being stored in a SQL table with a field type of varbinary(max) I also store the image content type.

使用 Microsoft ASP.NET Core MVC 和 Dapper，我试图从数据库中取回文件并将其呈现为图像.

Using Microsoft ASP.NET Core MVC and Dapper, I am trying to get the file back from the database and render it as an image.

这是我的文件模型:

using System;

namespace Brand.Models
{
    public class FileModel
    {
        public Guid ID { get; set; }
        public string FileName { get; set; }
        public string FileType { get; set; }
        public byte[] FileData { get; set; }
        public int FileLength { get; set; }
        public long Version { get; set; }
        public string FileSource { get; set; }
        public DateTime Created { get; set; }

        public FileModel() 
        {
            FileLength = 0;
            Version = 1;
            Created = DateTime.Now;
        }
    }
}

这些是我的功能:

public FileStreamResult GetFile(string FileID)
{
    return GetFile(new Guid(FileID));
}

public FileStreamResult GetFile(Guid FileID)
{
    using (SqlConnection connection = new SqlConnection(connectionString))
    {
        connection.Open();
        DynamicParameters dynamicParameters = new DynamicParameters();
        dynamicParameters.Add(@"ID", FileID);
        FileModel result = connection.Query<FileModel>("GetFile", dynamicParameters, commandType: CommandType.StoredProcedure).FirstOrDefault();
        Stream stream = new MemoryStream(result.FileData);
        return new FileStreamResult(stream, result.FileType);
    }
}

我用这种语法来称呼它:

I call this with this kind of syntax:

<img src="@fileExtensions.GetFile(content.FileID)" />

我在尝试此操作时收到 404 响应，因此显然我实施此操作的方式有问题.

I am getting a 404 response when I try this, so obviously something is wrong with the way I am implementing this.

推荐答案

下面的代码只是我的头，所以它可能需要一些调整，但它会给你基本的想法.

The below code is just off the top of my head, so it might need some tweaks, but it will give you the basic idea.

创建一个新的控制器并将你的方法放在那里:

Create a new controller and put your methods in there:

public ImageController : Controller
{
    public FileStreamResult GetFile(string FileID)
    {
        return GetFile(new Guid(FileID));
    }

    public FileStreamResult GetFile(Guid FileID)
    {
        using (SqlConnection connection = new SqlConnection(connectionString))
        {
            connection.Open();
            DynamicParameters dynamicParameters = new DynamicParameters();
            dynamicParameters.Add(@"ID", FileID);
            FileModel result = connection.Query<FileModel>("GetFile", dynamicParameters, commandType: CommandType.StoredProcedure).FirstOrDefault();
            Stream stream = new MemoryStream(result.FileData);
            return new FileStreamResult(stream, result.FileType);
        }
    }
}

然后在您的标记中，引用控制器:

then in your markup, reference the controller:

<img src="@Url.Action("GetFile", "Image", new {FileId = content.FileID})" />

这篇关于ASP.NET Core MVC，从数据库中获取文件，并渲染为图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持跟版网！