代码呢？用jquery+FormData的话需要设置processData为false不处理数据为键值对

processData 和 contentType 都设置为false了

                        ```//页面ajax发送
                        var formData = new FormData($("#btnImg")[0].files);
                                $.ajax({
                    type: "POST",
                    url: strUrl,
                    data: formData,
                    processData: false,
                    contentType: false,
                    success: function (data) {

                    },error: function (err) {

                    }
                })

后台ashx接收

 public void insertImg (HttpContext context) {
    context.Response.ContentType = "text/plain";
    string result = string.Empty;
    string filePath = string.Empty;
    string fileNewName = string.Empty;
    try {
        HttpFileCollection files = context.Request.Files;
        if (files.Count > 0)
        {
            fileNewName = DateTime.Now.ToString("yyyyMMddHHmmssff") + "_" + System.IO.Path.GetFileName(files[0].FileName);
            try { files[0].SaveAs(context.Server.MapPath("~/saveImg/"+fileNewName)); }
            catch {
                context.Response.Write("Error:"+filePath.ToString());
                context.Response.End();
                return;
            }
            result = "OK," + fileNewName + "";
        }
        else
        {
            result = "Error:错误代码：02，上传失败！";
        }
    }
    catch
    {
            result = "Error:错误代码：03，上传失败！";
    }
    context.Response.Write(result);
    context.Response.End();
}