Path.HasExtension Method

Definition

Namespace:

System.IO

Assemblies:

netstandard.dll, System.Runtime.dll

Overloads

Name	Description
HasExtension(ReadOnlySpan<Char>)	Determines whether the path represented by the specified character span includes a file name extension.
HasExtension(String)	Determines whether a path includes a file name extension.

HasExtension(ReadOnlySpan<Char>)

Source:

Path.cs

Determines whether the path represented by the specified character span includes a file name extension.

public:
 static bool HasExtension(ReadOnlySpan<char> path);

public static bool HasExtension(ReadOnlySpan<char> path);

static member HasExtension : ReadOnlySpan<char> -> bool

Public Shared Function HasExtension (path As ReadOnlySpan(Of Char)) As Boolean

Parameters

path

ReadOnlySpan<Char>

The path to search for an extension.

Returns

Boolean

true if the characters that follow the last directory separator character in the path include a period ("."), and the last such period is followed by one or more characters; otherwise, false.

Remarks

A trailing period in path is not considered an extension, even if an earlier period is followed by characters. For example, file.tar. has no extension.

See also

• File path formats on Windows systems

HasExtension(String)

Source:

Path.cs

Determines whether a path includes a file name extension.

public:
 static bool HasExtension(System::String ^ path);

public static bool HasExtension(string? path);

static member HasExtension : string -> bool

Public Shared Function HasExtension (path As String) As Boolean

Parameters

path

String

The path to search for an extension.

Returns

Boolean

true if the characters that follow the last DirectorySeparatorChar or AltDirectorySeparatorChar character in the path include a period (.), and the last such period is followed by one or more characters; otherwise, false.

Exceptions

ArgumentException

.NET Framework and .NET Core versions older than 2.1: path contains one or more of the invalid characters defined in GetInvalidPathChars().

Examples

The following example demonstrates the use of the HasExtension method.

string fileName1 = "myfile.ext";
string fileName2 = @"mydir\myfile";
string path = @"C:\mydir.ext\";
bool result;

result = Path.HasExtension(fileName1);
Console.WriteLine("HasExtension('{0}') returns {1}",
    fileName1, result);

result = Path.HasExtension(fileName2);
Console.WriteLine("HasExtension('{0}') returns {1}",
    fileName2, result);

result = Path.HasExtension(path);
Console.WriteLine("HasExtension('{0}') returns {1}",
    path, result);

// This code produces output similar to the following:
//
// HasExtension('myfile.ext') returns True
// HasExtension('mydir\myfile') returns False
// HasExtension('C:\mydir.ext\') returns False

Dim fileName1 As String = "myfile.ext"
Dim fileName2 As String = "mydir\myfile"
Dim pathname As String = "C:\mydir.ext\"
Dim result As Boolean

result = Path.HasExtension(fileName1)
Console.WriteLine("HasExtension('{0}') returns {1}", fileName1, result)

result = Path.HasExtension(fileName2)
Console.WriteLine("HasExtension('{0}') returns {1}", fileName2, result)

result = Path.HasExtension(pathname)
Console.WriteLine("HasExtension('{0}') returns {1}", pathname, result)

' This code produces output similar to the following:
'
' HasExtension('myfile.ext') returns True
' HasExtension('mydir\myfile') returns False
' HasExtension('C:\mydir.ext\') returns False

Remarks

Starting from the end of path, this method searches for a period (.), and stops at the first period it finds or at a DirectorySeparatorChar or AltDirectorySeparatorChar character. It returns true if it finds a period and that period isn't the last character of path. For example, Path.HasExtension("file.tar.") returns false.

For a list of common I/O tasks, see Common I/O Tasks.

See also

• File path formats on Windows systems
• File and Stream I/O
• How to: Read Text from a File
• How to: Write Text to a File