Question

我正在尝试通过ajax调用填充下拉列表我的代码工作正常，直到我以Json格式发回结果（对象列表）。

这是我试图填写的实体模型：

 public partial class stkInvoicesTypesTbl
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
    public stkInvoicesTypesTbl()
    {
        this.stkInvoicesTbls = new HashSet<stkInvoicesTbl>();
    }

    public int invTypesTableId { get; set; }
    public string invTypeDesc { get; set; }

    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public virtual ICollection<stkInvoicesTbl> stkInvoicesTbls { get; set; } //this property throw Exception and i think here is my problem
}

这是我的ajax调用和脚本代码

var InvType = []

// fetch invoice type from database
function LoadInvoiceType(element)
{   
    if (InvType.length == 0) {
        //ajax function to fetch data
        $.ajax({
            type: "GET",
            url: '/InvoiceItm/getInvoiceType',

            success: function (data) {
                InvType = data;

                renderInvoiceType(element);
            },
            error: function (data) {
                InvType = data;
            }
        })
    }
    else {
        //render invoice type to elements
        renderInvoiceType(element);
    }
}

function renderInvoiceType(element)
{
    var $ele = $(element);
    $ele.empty();

    $.each(InvType, function (i, val) {
        $ele.append($('<option/>').val(val.invTypesTableId).text(val.invTypeDesc));
    })
}

我的动作控制器：

public JsonResult getInvoiceType()
{
        List<stkInvoicesTypesTbl> InvoiceTypes = new List<stkInvoicesTypesTbl>();

        using (iraqEntities dc = new iraqEntities())
        {
            InvoiceTypes = dc.stkInvoicesTypesTbls.OrderBy(a => a.invTypeDesc).ToList();
        }

        return new JsonResult { Data = InvoiceTypes, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
}

我的观点：

<td><label for="input-text" class="col-sm-1 control-label">Invoice Type</label> </td>
            <td>
                <select type="text" id="InvoiceType" class="col-sm-3 form-control" onchange="LoadInvoiceType(this)"></select>

            </td>

我的列表在控制器中正确填充但是当我以json格式发送回来时（返回JsonResult ...），它返回错误。

以下是我调试的一些屏幕截图可能会有所帮助：

return my data from database and fill my list in controller

this property is generated automatically from Entity Framework (foreign key relation) and it's throwing an exception so I think my problem lies here

所以，任何人都可以帮助我解决我的问题

Answer 1

您需要在查询中包含属性stkInvoicesTbls

    using (iraqEntities dc = new iraqEntities())
    {
        InvoiceTypes = dc.stkInvoicesTypesTbls
                         .Include("stkInvoicesTbls")
                         .OrderBy(a => a.invTypeDesc)
                         .ToList();
    }

使用json和Entity Framework

1 个答案: