IQueryable，如何处理特殊情况

Question

我应该让 IQueryable 处理以下特殊情况：

s => s.Trusting == searchTrusting
s => s.Trusted == searchTrusted
s => s.Trusting == searchTrusting and s => s.Trusted == searchTrusted
other cases

我应该如何发出指定这些情况的 IQueryable 请求。我以前从未使用过 IQueryable。

我的同事建议我使用：

var specialCases = IQueryable.
IQueryable.

他的评论是：这种方法只能部分解决问题尝试结合 IQueryable 和单独的 if 每种情况。

如何实现结合IQueryable？

在他发表评论之前ifs处于if，else if，else if，else的状态为了获得相同的结果，我现有的解决方案使用了：（有效）

var domainTrustColl = _domainTrustRepository.GetDomainTrustItems().ToList().ConvertAll(new Converter<DomainTrustItem, DomainTrustModel>(DomainTrustModel.FromDomain));

domainTrustColl = domainTrustColl.Where(s => s.Trusting.Contains(searchTrusting)).Where(s => s.Trusted.Contains(searchTrusted)).Where(s => s.Type.Contains(searchType)).ToList();

            if (!string.IsNullOrEmpty(searchTrusting))
            {
                domainTrustColl = domainTrustColl.Where(s => s.Trusting == searchTrusting).Where(s => s.Trusted.Contains(searchTrusted)).Where(s => s.Type.Contains(searchType)).ToList();
            }
            if (!string.IsNullOrEmpty(searchTrusted))
            {
                domainTrustColl = domainTrustColl.Where(s => s.Trusting.Contains(searchTrusting)).Where(s => s.Trusted == searchTrusted).Where(s => s.Type.Contains(searchType)).ToList();
            }
            if (!string.IsNullOrEmpty(searchTrusting) && !string.IsNullOrEmpty(searchTrusted))
            {
                domainTrustColl = domainTrustColl.Where(s => s.Trusting == searchTrusting).Where(s => s.Trusted == searchTrusted).Where(s => s.Type.Contains(searchType)).ToList();
            }

Answer 1

从你的 LINQ 查询中，我发现这条语句是多余的

.Where(s => s.Type.Contains(searchType))

因此，您的 IQueryable 查询可以简化如下：

...

var query = domainTrustColl.Where(s => s.Type.Contains(searchType));

// Case - Both not selected
if (string.IsNullOrEmpty(searchTrusting) && string.IsNullOrEmpty(searchTrusted))
{
    // Handle no select any case
}
// Third case - Both selected
else if (!string.IsNullOrEmpty(searchTrusting) && !string.IsNullOrEmpty(searchTrusted))
{
    query = query.Where(s => s.Trusting == searchTrusting)
        .Where(s => s.Trusted == searchTrusted);
}
// First case
else if (!string.IsNullOrEmpty(searchTrusting))
{
    query = query.Where(s => s.Trusting == searchTrusting)
        .Where(s => s.Trusted.Contains(searchTrusted));
}
// Second case
else if (!string.IsNullOrEmpty(searchTrusted))
{
    query = query.Where(s => s.Trusting.Contains(searchTrusting))
        .Where(s => s.Trusted == searchTrusted);
}

domainTrustColl  = query.ToList();

最后，具体化查询以通过 .ToList() 执行查询。

IQueryable，如何处理特殊情况

IQueryable, how to handle particular cases

.net

c#

linq

iqueryable