Check if a Float number falls within a range using Extension Methods

Extension methods enable you to "add" methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. I was having a conversation with a bunch of C# 2.0 developers the other day who were planning to move to C# 3.0 and then 4.0. They had a requirement to check if a number falls within a specific range and wanted to see how this could be done in 3.0. I said use Extension Methods. Here’s some code that checks if a float number falls within a range, using an Extension Method


static class Program
public static void Main(string[] args)
float number = 23.5f;
if (number.CheckRange(20.0f, 25.5f))
Console.WriteLine("In Range");
Console.WriteLine("Out of Range");

static bool CheckRange(this float num, float min, float max)
return num > min && num < max;


Module Module1
Public Sub Main(ByVal args() As String)
Dim number As Single = 23.5F
If number.CheckRange(20.0F, 25.5F) Then
Console.WriteLine("In Range")
Console.WriteLine("Out of Range")
End If
End Sub

<System.Runtime.CompilerServices.Extension()> _
Private Function CheckRange(ByVal num As Single, _
ByVal min As Single, _
ByVal max As Single) As Boolean
num > min AndAlso num < max
End Function
End Module

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About The Author

Suprotim Agarwal
Suprotim Agarwal, Developer Technologies MVP (Microsoft Most Valuable Professional) is the founder and contributor for DevCurry, DotNetCurry and SQLServerCurry. He is the Chief Editor of a Developer Magazine called DNC Magazine. He has also authored two Books - 51 Recipes using jQuery with ASP.NET Controls. and The Absolutely Awesome jQuery CookBook.

Follow him on twitter @suprotimagarwal.

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