c# – 减去两个ViewBag值

不确定这是否是正确的方法.但是,我在视图中有两个文本框,由控制器中的Viewbag填充.它们是int值.一个值是库存单位数(Viewbag.stock),另一个是订购单位数(Viewbag.ordered).我有第三个文本框,我想显示Viewbag.Stock的值 – Viewbag.Ordered.

我尝试在控制器中执行此操作,但这并没有带来结果.我也试过在文本框的值中这样做,这也没有用.

这是我尝试完成此任务的第一种方式

模型

public int? OnHand { get; set; }
        public int? UnitsOrdered { get; set; }

调节器

ViewBag.Stock = r.FirstOrDefault().OnHand;
        ViewBag.Ordered = r.FirstOrDefault().UnitsOrdered;
        ViewBag.Total = ViewBag.Stock - ViewBag.Ordered;

视图

<div class="form-group">
        @Html.LabelFor(model => model.UnitsOrdered, (string)"Units On Hand ", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">              
            @Html.TextBox("OnHand", null, new { @class = "form-control", Value = ViewBag.Stock, @readonly = "readonly" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.UnitsOrdered, (string)"Number of Units Ordered", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.UnitsOrdered, new { htmlAttributes = new { @class = "form-control", @readonly = "readonly" } })
            @ViewBag.MyCountIntro @ViewBag.MyCount
            @Html.ValidationMessageFor(model => model.UnitsOrdered, "", new { @class = "text-danger" })

        </div>
    </div>

            <div class="col-md-10">
            @Html.TextBox("Remaining", null, new { @class = "form-control", Value = ViewBag.Total, @readonly = "readonly" })
            </div>

在上面的场景中,Viewbag.Stock是60.Viewbag.Ordered是2.Viewbag.Total应该是58.但相反,它是空白

我也尝试在视图中计算它本身.这也产生了空白.

<div class="col-md-10">
            @Html.TextBox("Remaining", null, new { @class = "form-control", Value = ViewBag.Stock - Viewbag.Ordered, @readonly = "readonly" })
        </div>

ViewBag本身会将值视为对象.在进行计算之前,您应该将该对象强制转换为适当的类型.

ViewBag.Total =(int)ViewBag.Stock – (int)ViewBag.Ordered;