Question

我收到错误（下面），我似乎无法将我的providerId转换为字符串

LINQ to Entities does not recognize the method 'System.String ToString(System.String)' method, and this method cannot be translated into a store expression

我试图转换它的原因是因为jQuery Datatables引发了一个错误：

DataTables warning: table id=example2 - Requested unknown parameter '0' for row 0. For more information about this error, please see http://datatables.net/tn/4

代码：

var allProviders = _db.CareProviders.AsQueryable();
var resultItems = allProviders.Select(a => new
{
    ProviderId = Convert.ToString(a.ProviderId), //convert to string
    CareServiceType = a.CareServiceType,
    CareServiceName = a.CareServiceName,
    Email = a.Email
}).ToList();

Answer 1

好吧，一个典型的解决方案是从数据库中获取数据，然后将其翻译成您的一面：

    var allProviders = _db.CareProviders.AsQueryable();
    var resultItems = allProviders.Select(a => new
    {
        ProviderId = a.ProviderId, // fetch it as it is
        CareServiceType = a.CareServiceType,
        CareServiceName = a.CareServiceName,
        Email = a.Email
    })
    // download results from DB and execute
    // rest of the query on the application side
    .AsEnumerable()
    // now convert
    .Select(a => new
    {
        ProviderId = a.ProviderId.ToString(), //convert to string
        CareServiceType = a.CareServiceType,
        CareServiceName = a.CareServiceName,
        Email = a.Email
    });

但是，有时这只是一种过度杀伤只是为了转换为字符串..

LINQ实际上通常会理解一些转换方法，但这取决于您的linq提供程序。您可以尝试并尝试以下方法之一：

... = SqlFunctions.StringConvert(a.ProviderId)
... = Convert.ToString(a.ProviderId)
... = a.ProviderId + ""

LINQ to Entities无法识别转换为字符串

1 个答案: