c# - LINQ - 无法使用 WHERE 条件创建

Question

我有以下方法:

    public DataTable.DataTablesPage<DataTable.UserModel> DataTableUserListByAttendees(int geoArea, int CurrentUserID)
    {
        var result = from i in _dbContext.Users
                     where i.GeographicalAreas.Any(p => p.GeoAreaID == geoArea)
                     select new DataTable.UserModel()
                     {
                         ID = i.ID,
                         Company = i.Company,
                         DCMember = (i.UserId != null),
                         FirstName = i.FirstName,
                         LastName = i.LastName
                     };

它工作正常，但它返回没有设置 geoArea proeprty 的实体。

    public DataTable.DataTablesPage<DataTable.UserModel> DataTableUserListByAttendees(int? geoArea, int CurrentUserID)
    {
        var result = from i in _dbContext.Users
                     where i.GeographicalAreas.Any(p => p.GeoAreaID == geoArea)
                     select new DataTable.UserModel()
                     {
                         ID = i.ID,
                         Company = i.Company,
                         DCMember = (i.UserId != null),
                         FirstName = i.FirstName,
                         LastName = i.LastName
                     };

我如何更改查询，以便它只返回设置了 geoArea 属性的实体(又名不为空)。

Answer 1

where (geoArea == null) || i.GeographicalAreas.Any(p => p.GeoAreaID == geoArea)

或有条件地将where添加到查询中