从 Web 下载 csv 文件 API 无法启动

Question

我有来自不同来源的示例代码，我想先尝试一下，然后再将其应用到我的代码中，这与我得到的示例非常相似。

我的控制器中有以下代码：

[Route("getcsv")]
    [HttpGet]
    public HttpResponseMessage GetCSV()
    {
        var data = new[]{   //Suppose you filter out these data

                           new{ Name="Ram", Email="ram@techbrij.com", Phone="111-222-3333" },
                           new{ Name="Shyam", Email="shyam@techbrij.com", Phone="159-222-1596" },
                           new{ Name="Mohan", Email="mohan@techbrij.com", Phone="456-222-4569" },
                           new{ Name="Sohan", Email="sohan@techbrij.com", Phone="789-456-3333" },
                           new{ Name="Karan", Email="karan@techbrij.com", Phone="111-222-1234" },
                           new{ Name="Brij", Email="brij@techbrij.com", Phone="111-222-3333" }
                  };

        HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
        result.Content = new StringContent(WriteTsv(data));
        result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
        result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment"); //attachment will force download
        result.Content.Headers.ContentDisposition.FileName = "RecordExport.csv";


        return result;
    }

    public string WriteTsv<T>(IEnumerable<T> data)
    {
        StringBuilder output = new StringBuilder();
        PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
        foreach (PropertyDescriptor prop in props)
        {
            output.Append(prop.DisplayName); // header
            output.Append("\t");
        }
        output.AppendLine();
        foreach (T item in data)
        {
            foreach (PropertyDescriptor prop in props)
            {
                output.Append(prop.Converter.ConvertToString(
                     prop.GetValue(item)));
                output.Append("\t");
            }
            output.AppendLine();
        }
        return output.ToString();
    }

我通过以下方式调用此方法：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title></title>

    <script type="text/javascript">
        function save() {
            window.open('https://localhost:44370/api/values/getcsv', '_blank', '');
        }
    </script>
</head>
<body>
    <a class="btn btn-primary" onclick="save()">Export</a>
</body>
</html>

所有这些都给我以下结果而不是下载文件：

我不知道我错过了什么。请帮忙！谢谢！

Answer 1

您的 Web 版本很可能使用了错误的语法 API。

如果使用 Asp.Net Core Web API，则需要重构为

[Route("api/[controller]")]
public class ValuesController: Controller {
    //GET api/values/getcsv
    [Route("getcsv")]
    [HttpGet]
    public IActionResult GetCSV() {
        var data = new[]{   //Suppose you filter out these data
           new{ Name="Ram", Email="ram@techbrij.com", Phone="111-222-3333" },
           new{ Name="Shyam", Email="shyam@techbrij.com", Phone="159-222-1596" },
           new{ Name="Mohan", Email="mohan@techbrij.com", Phone="456-222-4569" },
           new{ Name="Sohan", Email="sohan@techbrij.com", Phone="789-456-3333" },
           new{ Name="Karan", Email="karan@techbrij.com", Phone="111-222-1234" },
           new{ Name="Brij", Email="brij@techbrij.com", Phone="111-222-3333" }
        };

        var bytes = System.Text.Encoding.UTF8.GetBytes(WriteTsv(data));
        return File(bytes, "application/octet-stream", "RecordExport.csv");
    }

    //...code omitted for brevity

}

在 Asp.Net 中，核心 HttpResponseMessage 不再被视为管道的第一个 class 公民，而是像普通模型一样被序列化。

从 Web 下载 csv 文件 API 无法启动

Downloading a csv file from Web API does not start

export-to-csv

asp.net-web-api

httpresponsemessage