C# 基于bool值的LINQ查询重用

我正在尝试编写一个查询，它将基于输入变量包含以下两个条件之一：

!(from o in db.Products.Where(x => x.Company_ID == cid && x.IsDeleted != true)

或

我目前的方法，包括前一种情况，如下所示。我已经包括productExists，它将是一个参数，它决定我是想要上面的条件1还是条件2

public IQueryable<ProductImportViewModel> AllImports(int id, bool productExists)
{
    return (from t1 in db.Products_Staging
            where (t1.ImportFileId == id) && !(from o in db.Products.Where(x => x.Company_ID == cid && x.IsDeleted != true)
                                               select o.ProductName).Contains(t1.ProductName)
            select new ProductImportViewModel
            {
                Id = t1.Id
            }
}

---

如果有人能帮我，我将不胜感激。

像这样的事情也许：

where (t1.ImportFileId == id) && 
            (
                productExists==true
                &&
                !(from o in db.Products.Where(x => x.Company_ID == cid && x.IsDeleted != true).
                                                Select(o=> o.ProductName).Contains(t1.ProductName)
            )
            ||
            (
                productExists==false
                &&
                (from o in db.Products.Where(x => x.Company_ID == cid && x.IsDeleted != true).
                                                Select(o=> o.ProductName).Contains(t1.ProductName)
            )

你也可以这样做：

var query=(from o in db.Products
          .Where(x => x.Company_ID == cid && x.IsDeleted != true).
          Select(o=> o.ProductName);
------
where (t1.ImportFileId == id) && 
    (
        productExists && !query.Contains(t1.ProductName)
    )
    ||
    (
        !productExists && query.Contains(t1.ProductName)
    )

---

两个查询将产生相同的sql

谢谢。我就是这么做的。我只是想知道是否有更简洁的方法来做！

var query=(from o in db.Products
          .Where(x => x.Company_ID == cid && x.IsDeleted != true).
          Select(o=> o.ProductName);
------
where (t1.ImportFileId == id) && 
    (
        productExists && !query.Contains(t1.ProductName)
    )
    ||
    (
        !productExists && query.Contains(t1.ProductName)
    )