LINQ 相当于以下代码？

Question

我正在学习 LINQ，希望以下方法能提供一些帮助。如何重写以下方法来使用 LINQ？

private bool IsInList(string file, List<FileInfo> excelList)
{
    if (excelList != null && excelList.Count > 0)
    {
        foreach (FileInfo f in excelList)
        {
            if (string.Compare(f.FullName, file, StringComparison.OrdinalIgnoreCase) == 0)
            {
                return true;
            }
        }
    }

    return false;
}

Answer 1

我将更改第二个参数以接受 IEnumerable ，这样您就不会仅限于列表。

private bool IsInList(string file, IEnumerable<FileInfo> excelList)
{
    return excelList != null && excelList.Any(f => f.FullName.Equals(file, StringComparison.OrdinalIgnoreCase));
}

Answer 2

使用 lambda：

private bool IsInList(string file, List<FileInfo> excelList)
{
    return excelList != null && excelList.Any(f => string.Compare(f.FullName, file, StringComparison.OrdinalIgnoreCase) == 0);
}

Answer 3

像这样的东西：

private bool IsInList(string file, List<FileInfo> excelList)
{
    if (excelList == null) return false;
    return excelList.Any(f => string.Compare(f.FullName, file, StringComparison.OrdinalIgnoreCase) == 0));
}

Answer 4

尝试一下——完全未经测试。

private bool IsInList(string file, List<FileInfo> excelList)
{
    if (excelList != null && excelList.Count > 0)
    {
        return excelList.Any(f => string.Compare(f.FullName, file, StringComparison.OrdinalIgnoreCase) == 0);
    }

    return false;
}

Answer 5

这应该做...

if (excelList != null && excelList.Count > 0)
{
    return (from f in excelList
            where (string.Compare(f.FullName, file, StringComparison.OrdinalIgnoreCase) == 0)
            select f).Any();
}
return false;