运行 azure 函数时 HttpRequest 为 null

问：

我想在 c# 中使用 AzureFunctions 将文件上传到 azure blob 存储。

所以这是我的 azure 函数：

public static class AppartementFunc
{

    [Function("AppartementFunc")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] HttpRequest req, ILogger log)
    {
        string Connection = Environment.GetEnvironmentVariable("AzureWebJobsStorage");
        string containerName = Environment.GetEnvironmentVariable("ContainerName");
        Stream myBlob = new MemoryStream();
        var file = req.Form.Files["File"];
        myBlob = file.OpenReadStream();
        var blobClient = new BlobContainerClient(Connection, containerName);
        var blob = blobClient.GetBlobClient(file.FileName);
        await blob.UploadAsync(myBlob);
        return new OkObjectResult("file uploaded successfylly");
    }
}

我试图像这样从邮递员那里测试这个功能：

但是这一行会触发一个错误：var file = req.Form.Files["File"]

`System.NullReferenceException: 'Object reference not set to an instance of an object.'

req was null.`

我不知道为什么HttpRequest请求是NULL ！ 谁能帮我解决这个问题？