C# Eval Expression Supported Data Types

The primitive data types are predefined by the language, and they are named by reserved keywords. They represent the basic types of language.

The Z.Expressions.Eval manages the following list of C# primary types.

• object
• string
• bool
• byte
• char
• decimal
• double
• short
• int
• long
• sbyte
• float
• ushort
• uint
• ulong

You can add additional types by using the EvalContext.RegisterType method as shown below.

class Calculator
{
	public static int Add(int a, int b)
	{
		return a + b;
	}

	public static int Subtract(int a, int b)
	{
		return a - b;
	}
	public static int Multiply(int a, int b)
	{
		return a * b;
	}
	public static int Divide(int a, int b)
	{
		return a / b;
	}
}

public static void Example1()
{
	var context = new EvalContext();

	context.RegisterType(typeof(Calculator));

	List<string> expressions = new List<string>()
	{
		"Calculator.Add(10, 5)",
		"Calculator.Subtract(10, 5)",
		"Calculator.Multiply(10, 5)",
		"Calculator.Divide(10, 5)"
	};

    foreach (var expression in expressions)
    {
		var result = context.Execute<int>(expression);

		Console.WriteLine("{0}: {1}", expression, result);
	}
}

Let's run the above code and you will see the following output.

Calculator.Add(10, 5): 15
Calculator.Subtract(10, 5): 5
Calculator.Multiply(10, 5): 50
Calculator.Divide(10, 5): 2

You can also use the EvalContext.RegisterStaticMember method which allows you to use static member names without qualifying them with their namespace or type name as shown below.

public static void Example2()
{
	var context = new EvalContext();

	context.RegisterStaticMember(typeof(Calculator));

	List<string> expressions = new List<string>()
	{
		"Add(10, 5)",
		"Subtract(10, 5)",
		"Multiply(10, 5)",
		"Divide(10, 5)"
	};

	foreach (var expression in expressions)
    {
        var result = context.Execute<decimal>(expression);

        Console.WriteLine("{0}: {1}", expression, result);
    }
}