c# - System.IO.FileInfo 不区分大小写的搜索

Question

下面是我修改的一些代码，最初是从这里复制的:

http://msdn.microsoft.com/en-us/library/bb546159.aspx

我在一个目录中搜索文件名，它工作正常，除了我不知道如何让它大小写不敏感

System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(startFolder);

 // This method assumes that the application has discovery permissions 
 // for all folders under the specified path.
 IEnumerable<System.IO.FileInfo> fileList = dir.GetFiles("*.*", System.IO.SearchOption.AllDirectories);

 //Create the query
 IEnumerable<System.IO.FileInfo> fileQuery =
     from file in fileList
     where file.Extension == ".pdf"
     where file.Name.Contains(searchString, StringComparison.OrdinalIgnoreCase)
     orderby file.Name
     select file;

此行包含错误:

where file.Name.Contains(searchString, StringComparison.OrdinalIgnoreCase)

错误是:

Error   1   'string' does not contain a definition for 'Contains' and the best extension method overload 'System.Linq.ParallelEnumerable.Contains<TSource>(System.Linq.ParallelQuery<TSource>, TSource, System.Collections.Generic.IEqualityComparer<TSource>)' has some invalid arguments  C:\Users\k5opjdjc\Documents\Visual Studio 2013\Projects\Test_File_Search\Test_File_Search\Controllers\SearchController.cs   30  23  Test_File_Search

我已经搜索了几个小时，但找不到答案。如果有人可以提供帮助，我将不胜感激。

Answer 1

这应该可以解决问题:

where file.Name.IndexOf(searchString, StringComparison.CurrentCultureIgnoreCase) >= 0

(IndexOf 没有找到匹配的子串时返回-1)