如果Linq结果为空

var result = myCollection.Where(x => x.SomeProperty == someValue);
if (result.Any())
{
    // 处理非空结果集
}
else
{
    // 处理空结果集
}

var result = myCollection.Where(x => x.SomeProperty == someValue).DefaultIfEmpty();
foreach (var item in result)
{
    // 处理结果集
}

var result = myCollection.Where(x => x.SomeProperty == someValue);
if (result != null && result.Any())
{
    // 处理非空结果集
}
else
{
    // 处理空结果集
}