上传文件（单文件）（FormData）（前端代码+.NET服务器端）

由于样式需要不能直接用file，只能用文本框+按钮

<form class="form-horizontal form-bordered form-row-strippe"  enctype="multipart/form-data" method="post" name="fileinfo" id="fileinfo" data-toggle="validator">
                <div class="modal-body">
                    <div class="form-horizontal">
                        <div class="control-group">
                            <label class="control-label" style=" 125px;">
                                审批项目名称：</label>
                            <div class="controls" style="margin-left: 0px;">
                                <input type="text" id="id" name="id" style="display:none;" value="$id$" />
                                <input type="text" id="projectname" name="projectname" class="m-wrap large" value="$projectname$" />
                            </div>
                        </div>
                        <div class="control-group">
                            <label class="control-label" style=" 125px;">
                                审批项目说明：</label>
                            <div class="controls" style="margin-left: 0px;">
                                <input class="m-wrap large" type="text" id="projectinfo" name="projectinfo" value="$projectinfo$" />
                            </div>
                        </div>
                        <div class="control-group">
                            <label class="control-label" style=" 125px;">
                                审批项目文件：</label>
                            <div class="controls" style="margin-left: 0px;">
                                <input type="file" id="filepath" name="filepath" style="display:none" onchange="changetext()" />
                                <input class="m-wrap" type="text" id="pathfile" name="pathfile" readonly="readonly" value="$filepath$" />
                                <input class="btn green" type="button" value="选择文件" id="uploadpath" />
                            </div>
                        </div>
                    </div>
                </div>
                <div class="modal-footer bg-info">
                    <input class="btn blue" type="button" id="btnsubmit" value="提交" onclick="update()" data-dismiss="modal" />
                    <button type="button" class="btn green" data-dismiss="modal">
                        取消</button>
                </div>
            </form>

<script type="text/javascript">
    jQuery(document).ready(function () {
        $('#uploadpath').click('click', function () {
            $('#filepath').trigger('click');
        });
    })
    function changetext()
    {
        if ($("#filepath").val() == "") {
            //当用户没有选择文件时,不修改原有路径
        }
        else {
            $("#pathfile").val($("#filepath").val());
        }
    }
    function update() {
        var projectname = $("#projectname").val();
        var projectinfo = $("#projectinfo").val();
        var filepath = $("#pathfile").val();
        //var formData = new FormData($("#fileinfo")[0]);//两者皆可
        var formData = new FormData(document.forms.namedItem("fileinfo"));
        formData.append("id", $id$);
        $.ajax({
            url: "/ApprovalProcessNoView/queryeditproject",
            type: "POST",
            data: formData,
            async: false,
            cache: false,
            contentType: false,
            processData: false,
            success: function (data) {
                alert(data.msg);
            },
            error: function (data) {
                alert(data.msg);
            }
        });
    }
</script>

returnresult rr = new returnresult();
            string projectname = Request.Form["projectname"];
            string projectinfo = Request.Form["projectinfo"];
            HttpPostedFileBase pathfile = Request.Files["filepath"];
            long id = Request.Form["id"].ToLong();

            string path = "/UF/Uploads/myfile";
            //获取上传目录 转换为物理路径
            string uploadPath = Server.MapPath(path);
            //判断目录是否存在
            if (!Directory.Exists(uploadPath))
            {
                Directory.CreateDirectory(uploadPath);
            }
            //保存文件的物理路径
            string saveFile = uploadPath + pathfile.FileName;
            //保存图片到服务器
            try
            {
                pathfile.SaveAs(saveFile);
                rr.status = true;
            }
            catch (Exception)
            {
                rr.status = false;
                rr.msg = "文件上传失败";
            }

主要使用：FormData

效果：将文件和其他需要上传的数据一起上传