How to get the first occurrence of char in a Substring?

Question

I am trying to get the first occurrence at my starting point of a substring:

string dir = Request.MapPath(Request.ApplicationPath) + "\\App_GlobalResources\\"; foreach (var file in Directory.EnumerateFiles(dir, "*.resx")) { ddlResources.Items.Add(new ListItem { Text = file.Substring(firstoccuranceof("."), file.LastIndexOf(".")), Value = file }); } 

if I do file.Substring (file.IndexOf ("."), file.LastIndexOf (".")), I get an error

Answer 1

To answer your real question, you can use string.IndexOf to get the first occurrence of a character. Note that you need to subtract this value from your LastIndexOf call, since Substring second parameter - the number of characters to extract, not the start and end index.

However ... Instead of parsing the names, you can simply use Path.GetFilenameWithoutExtension to get the file name directly.

Answer 2

First appearance

 String.IndexOf('.') 

Last appearance

 String.LastIndexOf('.') 

Answer 3

Use the IndexOf and LastIndexOf string methods to get the index of the first and last occurrence of the search string. You can use the System.IO.Path.GetExtension() , System.IO.Path.GetFileNameWithoutExtension() and System.IO.Path.GetDirectoryName() methods to analyze the path.

For instance,

 string file = @"c:\csnet\info.sample.txt"; Console.WriteLine(System.IO.Path.GetDirectoryName(file)); //c:\csnet Console.WriteLine(System.IO.Path.GetFileName(file)); //info.sample.txt Console.WriteLine(System.IO.Path.GetFileNameWithoutExtension(file));//info.sample Console.WriteLine(System.IO.Path.GetExtension(file)); //.txt 

Answer 4

file.IndexOf ("")

It should be the first appearance of ".". Otherwise, it will return -1 if not found.

Answer 5

I think in your particular case you are NOT trying to get IndexOf ... Instead, you need to use 0 because you are trying to create a key based on the file name if you understand correctly:

 `ddlResources.Items.Add(new ListItem(file.Substring(0, file.LastIndexOf(".")), file ));` 

Also, you have "{}" there, as in the new ListItem {...}, which will also throw a syntax error ... Anyway, look ..

Answer 6

Since the original question is tagged with [regex], I will provide the following solution, however, the best answer for simple path analysis using .NET is not by regular expression.

 //extracts "filename" from "filename.resx" string name = Regex.Match("filename.resx", @"^(.*)\..+?$").Groups[1].Value; 

Instead, use an answer that relies on the Path class for simplicity. Other answers contain this information.