Question

我正在尝试构建我的代码并能够更好地维护我的一些LINQ查询。实际上我创建了一个带有一些函数的新助手类，但是我在另一个IQueryable函数中执行了一些IQueryable函数时遇到了一些问题。

当我执行函数SupplierMappings.GetSupplierAssociatedRT(int supplierID)时，我收到以下错误：

方法'System.Linq.IQueryable`1 [VMPortal.DataAccessLayer.CostCentre]
GetSupplierAssociatedCCPerRT（Int32，Int32）'没有支持的SQL转换。

我做错了什么？以下是相关代码的一部分：

public class SupplierMappings
{
    private static DataLayer dl = DataLayer.GetDataContext();

    public static IQueryable<ResourceType> GetSupplierAvailableRT(int supplierID)
    {
        return dl.ResourceTypes.Where(x =>
            dl.SuppliersCompanies2.Any(y => y.SupplierID == supplierID
                && y.ResourceTypeID == x.ResourceTypeID
                && y.StatusID == (short)SuppliersCompaniesStatusEnum.Active));
    }

    public static IQueryable<ResourceType> GetSupplierAssociatedRT(int supplierID)
    {
        return GetSupplierAvailableRT(supplierID).Where(x =>
            // Check if we have at least one CC associated with that RT
            GetSupplierAssociatedCCPerRT(supplierID, x.ResourceTypeID).Count() >= 1);
    }

    public static IQueryable<CostCentre> GetSupplierAvailableCCPerRT(int supplierID, int rtID)
    {
        return dl.CostCentres.Where(x => x.StatusID == (short)CostCentersStatusEnum.Active
            // Check than the supplier is mapped at supplier level at same company & RT
            && dl.SuppliersCompanies2.Any(y => y.CompanyID == x.CompanyID
                && y.SupplierID == supplierID
                && y.ResourceTypeID == rtID
                && y.StatusID == (short)SuppliersCompaniesStatusEnum.Active)
            // Check than the PA is active
            && x.DeliveryGroup.StatusID == (short)DeliveryGroupsStatusEnum.Active);
    }

    public static IQueryable<CostCentre> GetSupplierAssociatedCCPerRT(int supplierID, int rtID)
    {
        return GetSupplierAvailableCCPerRT(supplierID, rtID).Where(x =>
            dl.SuppliersCostCentre2.Count(y => y.SupplierID == supplierID
                && y.StatusID == (short)SuppliersCostCentreStatusEnum.Inactive
                && y.ResourceTypeID == rtID) != dl.SuppliersCompanies2.Count(y => y.SupplierID == supplierID
                    && x.CompanyID == y.CompanyID
                    && y.StatusID == (short)SuppliersCompaniesStatusEnum.Active
                    && y.ResourceTypeID == rtID)
            && dl.SuppliersPracticeAreas.Count(y => y.SupplierID == supplierID
                && y.StatusID == (short)SuppliersPracticeAreaStatusEnum.Inactive
                && y.ResourceTypeID == rtID) != dl.SuppliersCompanies2.Count(y => y.SupplierID == supplierID
                    && x.CompanyID == y.CompanyID
                    && y.StatusID == (short)SuppliersCompaniesStatusEnum.Active
                    && y.ResourceTypeID == rtID));
    }
}

Answer 1

很可惜但是在linq to sql中你不能使用你定义的方法来返回除表达式之外的任何东西。并且可以转换为sql查询的表达式数量有限（此转换在linqtosql库中定义）。所以你不能做你想做的事。您可以尝试内联函数。

Linq2Sql IQueryable在另一个IQueryable里面

1 个答案: