There is no generic Where method in the System.Linq.Queryable type. It is compatible with arguments and arguments of the supplied type.

I want to get a specific record using IQueryable. But I get the error "There is no universal Where method on the type System.Linq.Queryable compatible with arguments and arguments of the supplied type. No type arguments should be provided if the method is not general. '. I got the selected row identifier, but I can’t display it. Here is my code.

 internal static IQueryable GetRecordsFromPrimaryKeys(this IQueryable datasource, List<FilterDescriptor> primaryKeys)
    {
        IQueryable data = datasource;

        ParameterExpression paramExp = null;
        bool firstLoop = false;
        System.Linq.Expressions.Expression predicate = null;

        var RecordType = datasource.GetObjectType();
        paramExp = RecordType.Parameter();

        foreach (FilterDescriptor primaryKey in primaryKeys)
        {
            if (!(firstLoop))
            {
                predicate = data.Predicate(paramExp, primaryKey.ColumnName, primaryKey.Value, FilterType.Equals, false, RecordType);
                firstLoop = true;
            }
            else
            {
                predicate = predicate.AndPredicate(data.Predicate(paramExp, primaryKey.ColumnName, primaryKey.Value, FilterType.Equals, false, RecordType));
            }
        }

        if (paramExp != null && predicate != null)
        {
            var lambda = Expression.Lambda(predicate, paramExp);
            data = data.Provider.CreateQuery(
                       Expression.Call(
                       typeof(Queryable),
                       "Where",
                       new Type[] { data.ElementType },
                       data.Expression,
                       lambda
                       )
                   );

        }

        return data;
    }

My code works well for IEnumerable / IQueryable / ICollection. But it throws an exception when I specify a class with the virtual keyword and type as ICollection. My code

public class RoomType
{
    public int ID { get; set; }

    [MaxLength(10, ErrorMessage = "Room code cannot be longer than 10 characters.")]
    public string Code { get; set; }

    [MaxLength(50, ErrorMessage = "Room name cannot be longer than 50 characters.")]
    public string Name { get; set; }

    public virtual ICollection<RoomCategory> RoomCategories { get; set; }
}

"RecordType" "virtual". , . .

, . .

.