Convert.ToBoolean Method in C#

The Convert.ToBoolean method in C# converts a specified value to an equivalent Boolean value. This method follows specific rules depending on the input type − numeric types return false if zero, true otherwise; string values are parsed based on their content.

Syntax

Following is the syntax for the Convert.ToBoolean method −

public static bool ToBoolean(object value);
public static bool ToBoolean(string value);
public static bool ToBoolean(int value);
public static bool ToBoolean(double value);
// Other overloads for different data types

Parameters

• value − The value to convert to a Boolean. Can be a numeric type, string, or object.

Return Value

Returns true or false based on the conversion rules for the specific data type.

Conversion Rules

Using Convert.ToBoolean with Numeric Types

Example

using System;

public class Demo {
   public static void Main() {
      double doubleNum = 3.4;
      int zeroInt = 0;
      int nonZeroInt = 42;
      
      bool boolFromDouble = Convert.ToBoolean(doubleNum);
      bool boolFromZero = Convert.ToBoolean(zeroInt);
      bool boolFromNonZero = Convert.ToBoolean(nonZeroInt);
      
      Console.WriteLine("{0} as a Boolean = {1}", doubleNum, boolFromDouble);
      Console.WriteLine("{0} as a Boolean = {1}", zeroInt, boolFromZero);
      Console.WriteLine("{0} as a Boolean = {1}", nonZeroInt, boolFromNonZero);
   }
}

The output of the above code is −

3.4 as a Boolean = True
0 as a Boolean = False
42 as a Boolean = True

Using Convert.ToBoolean with String Values

Example

using System;

public class StringToBoolDemo {
   public static void Main() {
      string trueString = "True";
      string falseString = "false";
      string nullString = null;
      
      bool boolFromTrue = Convert.ToBoolean(trueString);
      bool boolFromFalse = Convert.ToBoolean(falseString);
      bool boolFromNull = Convert.ToBoolean(nullString);
      
      Console.WriteLine("'{0}' as Boolean = {1}", trueString, boolFromTrue);
      Console.WriteLine("'{0}' as Boolean = {1}", falseString, boolFromFalse);
      Console.WriteLine("null as Boolean = {0}", boolFromNull);
   }
}

The output of the above code is −

'True' as Boolean = True
'false' as Boolean = False
null as Boolean = False

Exception Handling

The method throws a FormatException when the string value is not "True" or "False" −

Example

using System;

public class ExceptionDemo {
   public static void Main() {
      string invalidString = "maybe";
      
      try {
         bool result = Convert.ToBoolean(invalidString);
         Console.WriteLine("Result: " + result);
      }
      catch (FormatException ex) {
         Console.WriteLine("FormatException: " + ex.Message);
      }
   }
}

The output of the above code is −

FormatException: String 'maybe' was not recognized as a valid Boolean.

Conclusion

The Convert.ToBoolean method provides a reliable way to convert various data types to Boolean values. For numeric types, zero converts to false and non-zero to true. For strings, only "True" and "False" (case-insensitive) are valid inputs, while invalid strings throw a FormatException.