Boolean.CompareTo(Object) Method in C#

The Boolean.CompareTo(Object) method in C# compares the current Boolean instance to a specified object and returns an integer that indicates their relationship to one another. This method is useful for sorting Boolean values or implementing custom comparison logic.

Syntax

Following is the syntax −

public int CompareTo(object obj);

Where obj is an object to compare to this instance, or null.

Return Value

The method returns an integer value indicating the relationship between the current instance and the specified object −

• Less than zero: This instance is false and obj is true

• Zero: This instance and obj have the same Boolean value

• Greater than zero: This instance is true and obj is false, or obj is null

Using CompareTo() with Same Values

Example

using System;

public class Demo {
   public static void Main() {
      bool b1 = false;
      object b2 = false;
      int res = b1.CompareTo(b2);
      
      if (res > 0)
         Console.WriteLine("b1 > b2");
      else if (res < 0)
         Console.WriteLine("b1 < b2");
      else
         Console.WriteLine("b1 = b2");
      
      Console.WriteLine("Comparison result: " + res);
   }
}

The output of the above code is −

b1 = b2
Comparison result: 0

Using CompareTo() with Different Values

Example

using System;

public class Demo {
   public static void Main() {
      bool b1 = false;
      object b2 = true;
      int res1 = b1.CompareTo(b2);
      Console.WriteLine("false.CompareTo(true) = " + res1);
      
      bool b3 = true;
      object b4 = false;
      int res2 = b3.CompareTo(b4);
      Console.WriteLine("true.CompareTo(false) = " + res2);
      
      bool b5 = true;
      object nullObj = null;
      int res3 = b5.CompareTo(nullObj);
      Console.WriteLine("true.CompareTo(null) = " + res3);
   }
}

The output of the above code is −

false.CompareTo(true) = -1
true.CompareTo(false) = 1
true.CompareTo(null) = 1

Handling Invalid Object Types

When the object passed is not a Boolean type, the method throws an ArgumentException −

Example

using System;

public class Demo {
   public static void Main() {
      bool b1 = true;
      object invalidObj = "Hello";
      
      try {
         int res = b1.CompareTo(invalidObj);
         Console.WriteLine("Result: " + res);
      }
      catch (ArgumentException ex) {
         Console.WriteLine("Exception: " + ex.Message);
      }
   }
}

The output of the above code is −

Exception: Object must be of type Boolean.

Conclusion

The Boolean.CompareTo(Object) method provides a standardized way to compare Boolean values, returning negative, zero, or positive integers based on the comparison. It treats false as less than true and handles null objects by considering them less than any Boolean value.