Json的问题

Question

我有动态创建Json这个奇怪的问题....由于某种原因，这不起作用

var jsonData = new
        {
            total = totalPages,
            page = page,
            records = totalRecords,
            rows = (
                from company in companies
                select new
                {
                    i = company.Id,
                    cell = new string[] { company.Id.ToString(), "<a href=\""+Url.Action("Edit",new{id=company.Id})+"\">"+company.Name.ToString()+"</a>" }
                }).ToArray()
        };

它给了我一个奇怪的“无法将表达式.......转换成sql”异常

但是通过这个微小的改变它可以正常工作

var jsonData = new
            {
                total = totalPages,
                page = page,
                records = totalRecords,
                rows = (
                    from company in companies
                    select new
                    {
                        i = company.Id,
                        cell = new string[] { company.Id.ToString(), "<a href=\""+Url.Action("Edit",new{id=5})+"\">"+company.Name.ToString()+"</a>" }
                    }).ToArray()
            };

请注意，更改只是使id = 5而不是动态。

此外，这种方法也正常，但我不喜欢它。

var jsonData = new
        {
            total = totalPages,
            page = page,
            records = totalRecords,
            rows = (
                from company in companies
                select new
                {
                    i = company.Id,
                    cell = new string[] { company.Id.ToString(), "<a href=\"Edit/"+company.Id+"\">"+company.Name.ToString()+"</a>" }
                }).ToArray()
        };

Answer 1

我不确定这是否会解决您的问题，但假设companies是来自DataContext的IQueryable，请尝试在其上调用ToList（），以便select表达式不会被发送到数据库。

var jsonData = new
{
    total = totalPages,
    page = page,
    records = totalRecords,
    rows = (
        from company in companies.ToList()
        select new
        {
            i = company.Id,
            cell = new string[] { company.Id.ToString(), "<a href=\""+Url.Action("Edit",new{id=company.Id})+"\">"+company.Name.ToString()+"</a>" }
        }).ToArray()
};

Answer 2

它正在尝试将i转换为SQL并失败。生成的查询接近

SELECT companies.Id,
    '<a href=\"Edit/' + companies.Id + '\">' + companies.Name + '</a>'
FROM companies

基本上，您的字符串连接正在发送到您的SQL服务器。