C# Eval Expression How to use Register & Unregister Methods in C# Eval Expression library

In the C# Eval Expression, the library is unaware of any namespace, class, method, or anything else besides what has been registered by default. Even if we included a lot of namespaces and objects by default such as System.Linq, DataTable, and Math for most basic cases, that is often not enough, and you need to register or even unregister on your side what is missing.

Register Methods

The Register methods allow you to add types, methods, properties, fields, values, and even keywords that you can use in the library.

Name Description
RegisterAlias The RegisterAlias method registers an alias for a variable, constant, method or type name. For example, if you register the alias "mymath" for the class "System.Math", you can now create an expression such as "mymath.Min(1, 2)".
RegisterAssembly The RegisterAssembly method registers all types from the assemblies provided.
RegisterAutoAddMissingTypeAssembly The RegisterAutoAddMissingTypeAssembly method registers assemblies in which the option `AutoAddMissingTypes` or `RetryAndThrowMissingTypes` is allowed to retrieve types.
RegisterDefaultAliasSafe The RegisterDefaultAliasSafe method registers types, members and extension methods of all safe types considered safe (Array, Dictionary, List, Tuple, etc.). You can find the complete list here:
RegisterDefaultAliasUnsafe The RegisterDefaultAliasUnsafe method registers types , members and extension methods of some types that might be considered more unsafe such as (Console, DirectioryInfo, FileInfo, etc.). You can find the complete list here:
RegisterDomainAssemblies The RegisterDomainAssemblies method registers all types from all assemblies loaded in the current domain. This method is only supported in the .NET Framework.
RegisterExtensionMethod The RegisterExtensionMethod method registers all extension methods from the types or method list provided.
RegisterGlobalConstant The RegisterGlobalConstant method registers a global constant value. The constant value is shared across all evaluations but cannot be modified (not writable).
RegisterGlobalVariable The RegisterGlobalVariable method registers a global variable value. This variable value is shared across all evaluations and can be modified.
RegisterKeyword The RegisterKeyword method registers a keyword for the specified extension methods. For example, if you register the keyword "isin" for the extension method "IsIn", you can now create an expression such as "x isin list".
RegisterLocalVariable The RegisterLocalVariable method registers a local variable value. This variable value is not shared across all evaluations and can be modified. In other words, the value is only modified for the current evaluation and doesn't impact the other evaluations.
RegisterMember The RegisterMember method registers all instance members from the types or fields list provided. A member is a Property, Field, Method, or Constructor.
RegisterNamespace The RegisterNamespace method registers all types in the specified assembly under the specified namespaces.
RegisterStaticField The RegisterStaticField method registers all static fields from the types or fields list provided.
RegisterStaticMember The RegisterStaticMember method registers all static members from the types or members list provided. A member is a Property, Field or Method.
RegisterStaticMethod The RegisterStaticMethod method registers all static methods from the types or fields list provided.
RegisterStaticProperty The RegisterStaticProperty method registers all static properties from the types or properties list provided.
RegisterType The RegisterType method registers all types provided. The method also registers extension methods from types but doesn't register other static members. For example, if you register the type "Z.MyNamespace.MyClass", you can now create an expression such as "new MyClass()" or any extension methods from this type.

Unregister Methods

The Unregister methods allows you to remove types, members, and anything else that has been added previously to the library. An excellent way to start fresh is using the UnregisterAll method, which will unregister everything.

Name Description
UnregisterAlias The UnregisterAlias method unregisters an alias for a variable, constant, static method or type name.
UnregisterAll The UnregisterAll method unregisters everything (alias, keyword, member, type and more).
UnregisterAssembly The UnregisterAssembly method unregister all types from the assemblies provided.
UnregisterAutoAddMissingTypeAssembly The UnregisterAutoAddMissingTypeAssembly method unregisters assemblies in which the option `AutoAddMissingTypes` or `RetryAndThrowMissingTypes` is allowed to retrieve types.
UnregisterExtensionMethod The UnregisterExtensionMethod method unregisters all extension methods from the types or method list provided.
UnregisterGlobalConstant The UnregisterGlobalConstant method unregisters a global constant value.
UnregisterGlobalVariable The UnregisterGlobalVariable method unregisters a global variable value.
UnregisterKeyword The UnregisterKeyword method unregisters a keyword for the specified extension methods.
UnregisterLocalVariable The UnregisterLocalVariable method unregisters a local variable value.
UnregisterMember The UnregisterMember method unregisters all instance members from the types or fields list provided.
UnregisterNamespace The UnregisterNamespace method unregisters all types in the specified assembly under the specified namespaces.
UnregisterStaticField The UnregisterStaticField method unregisters all static fields from the types or fields list provided.
UnregisterStaticMember The UnregisterStaticMember method unregisters all static fields from the types or fields list provided.
UnregisterStaticMethod The UnregisterStaticMethod method unregisters all static methods from the types or fields list provided.
UnregisterStaticProperty The UnregisterStaticProperty method unregisters all static properties from the types or properties list provided.
UnregisterType The UnregisterType method unregisters all types provided. The method also unregisters extension methods from types

You will find examples for Unregister methods inside their corresponding Register methods.

IsRegistered Methods

The IsRegistered method allows you to check if a type, member, or anything else has already been registered to our library.

Name Description
IsRegisteredAlias The IsRegisteredAlias method returns true if the alias or the alias for a specific name provided is registered.
IsRegisteredAssembly The IsRegisteredAssembly method returns true if all types from the assembly provided is registered.
IsRegisteredAutoAddMissingTypeAssembly The IsRegisteredAutoAddMissingTypeAssembly method returns true if the assembly is part in which the option `AutoAddMissingTypes` or `RetryAndThrowMissingTypes` is allowed to retrieve types.
IsRegisteredExtensionMethod The IsRegisteredExtensionMethod method returns true if all extension methods from the type or extension method provided is registered.
IsRegisteredGlobalConstant The IsRegisteredGlobalConstant method returns true if the global constant name or the global constant name with the value provided is registered.
IsRegisteredGlobalVariable The IsRegisteredGlobalVariable method returns true if the global variable name or the global variable name with the value provided is registered.
IsRegisteredKeyword The IsRegisteredKeyword method returns true if the keyword provided is registered.
IsRegisteredLocalVariable The IsRegisteredLocalVariable method returns true if the local variable name or the local variable name with the value provided is registered.
IsRegisteredMember The IsRegisteredMember method returns true if all instance members from the type or member provided is registered.
IsRegisteredNamespace The IsRegisteredNamespace method returns true if all types in the assembly under the specified namespaces provided is registered.
IsRegisteredStaticField The IsRegisteredStaticField method returns true if all static fields from the type or field provided is registered.
IsRegisteredStaticMember The IsRegisteredStaticMember method returns true if all static members from the type or member provided is registered.
IsRegisteredStaticMethod The IsRegisteredStaticMethod method returns true if all static methods from the type or method provided is registered.
IsRegisteredStaticProperty The IsRegisteredStaticProperty method returns true if all static properties from the type or property provided is registered.
IsRegisteredType The IsRegisteredType method returns true if the type or type name provided is registered.

You will find examples for IsRegistered methods inside their corresponding Register methods.

RegisterAlias

The RegisterAlias method registers an alias for a variable, constant, method or type name. For example, if you register the alias "mymath" for the class "System.Math", you can now create an expression such as "mymath.Min(1, 2)".

In this example, we will use the alias instead of the real namespace, method, and variable names. In the first example, we will use the mymath and One alias that will replace the Math namespace and x variable name. In the second example, we will also use the MathMin that will be an alias for the method Math.Min.

Afterward, we will use the method IsRegisteredAlias to show that the alias was registered, then use the method UnregisterAlias to remove it and check again to show that the alias was successfully unregistered.

// Global Context: EvalManager.DefaultContext.RegisterAlias("mymath", "Math");
// Global Context: EvalManager.DefaultContext.UnregisterAlias("mymath");
// Global Context: EvalManager.DefaultContext.IsRegisteredAlias("mymath");

var context = new EvalContext();
context.RegisterAlias("mymath", "Math");
context.RegisterAlias("One", "x");
context.RegisterAlias("MathMin", "Min");

// "mymath" is an alias for "Math"
// "One" is an alias for "x" (the parameter)
var r1 = context.Execute("mymath.Min(One, y)", new { x = 1, y = 2 });
Console.WriteLine("1 - Result: " + r1);

// "MathMin" is an alias for "Min" method from "Math.Min"
var r2 = context.Execute("MathMin(One, y)", new { x = 1, y = 2 });
Console.WriteLine("2 - Result: " + r2);

// Check that the alias "mymath" is registered
var r3 = context.IsRegisteredAlias("mymath");
Console.WriteLine("3 - Result: " + r3);

// Unregister the "mymath" alias
context.UnregisterAlias("mymath");

// Check that the alias "mymath" has been successfully unregistered
var r4 = context.IsRegisteredAlias("mymath");
Console.WriteLine("4 - Result: " + r4);

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RegisterAssembly

The RegisterAssembly method registers all types from the assemblies provided.

In this example, we will register our assembly to be able to use the Program.AddDemo static methods. Afterward, we will use the method IsRegisteredAssembly to check that the assembly was indeed registered, the method UnregisterAssembly to unregister the assembly, and finally, check again with the method IsRegisteredAssembly that the assembly has been successfully unregistered.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterAssembly(typeof(Program).Assembly);
		
		var context = new EvalContext();
		context.RegisterAssembly(typeof(Program).Assembly);
		
		var r1 = context.Execute<int>("Program.AddDemo(x, y)", new { x = 1, y = 2 });
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if the assembly is registered
		var r2 = context.IsRegisteredAssembly(typeof(Program).Assembly);
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister the assembly
		context.UnregisterAssembly(typeof(Program).Assembly);
		
		// Check if the assembly has been successfully unregistered
		var r3 = context.IsRegisteredAssembly(typeof(Program).Assembly);
		Console.WriteLine("3 - Result: " + r3);		
	}
	
	public static int AddDemo(int x, int y)
	{
		return x + y;
	}
}

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RegisterAutoAddMissingTypeAssembly

The RegisterAutoAddMissingTypeAssembly method registers assemblies in which the option AutoAddMissingTypes or RetryAndThrowMissingTypes is allowed to retrieve types.

In this example, we will use the same logic as we did with the RegisterAssembly method. The major difference between both methods is types when using RegisterAutoAddMissingTypeAssembly are only added to the expression if needed, and it requires either the option AutoAddMissingTypes or RetryAndThrowMissingTypes to work.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterAutoAddMissingTypeAssembly(typeof(Program).Assembly);
		
		var context = new EvalContext();
		context.RegisterAutoAddMissingTypeAssembly(typeof(Program).Assembly);
		context.AutoAddMissingTypes = true;
		
		var r1 = context.Execute<int>("Program.AddDemo(x, y)", new { x = 1, y = 2 });
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if the assembly is registered
		var r2 = context.IsRegisteredAutoAddMissingTypeAssembly(typeof(Program).Assembly);
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister the assembly
		context.UnregisterAutoAddMissingTypeAssembly(typeof(Program).Assembly);
		
		// Check if the assembly is registered has been successfully unregistered
		var r3 = context.IsRegisteredAutoAddMissingTypeAssembly(typeof(Program).Assembly);
		Console.WriteLine("3 - Result: " + r3);		
	}
	
	public static int AddDemo(int x, int y)
	{
		return x + y;
	}
}

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RegisterDefaultAliasSafe

The RegisterDefaultAliasSafe method registers types, members and extension methods of all safe types considered safe (Array, Dictionary, List, Tuple, etc.). You can find the complete list here:

In this example, we will unregister all types and then register only types included in the RegisterDefaultAliasSafe methods. First, we will create a dictionary that is part of the registered types. Then we will try to create a DataTable but it will fail as our library excludes it by default as we flag this object unsafe due to method such as Load and WriteXml.

// Global Context: EvalManager.DefaultContext.RegisterDefaultAliasSafe();

var context = new EvalContext();
context.UnregisterAll();
context.RegisterDefaultAliasSafe();

// 1 - You can access the Dictionary object since the type has been registered in the RegisterDefaultAliasSafe
var r1 = context.Execute<int>(@"var dict = new Dictionary<string, object>(); return dict.Count;");

Console.WriteLine("1 - Result: " + r1);

try
{
	var fail = context.Execute<int>("var dt = new DataTable(); return dt.Rows.Count;");
}
catch(Exception ex)
{
	// 2 - However, you cannot access the DataTable because we excluded this type due to methods such as `Load`  and `WriteXml`
	Console.WriteLine("2 - Exception: " + ex.Message);
}

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To learn more and see what contains this method, see Register Default Alias Safe/Unsafe

RegisterDefaultAliasUnsafe

The RegisterDefaultAliasUnsafe method registers types , members and extension methods of some types that might be considered more unsafe such as (Console, DirectoryInfo, FileInfo, etc.). You can find the complete list here:

In this example, we will unregister all types and then register only types included in the RegisterDefaultAliasUnsafe methods. In fact, all types from the RegisterDefaultAliasUnsafe are already registered by default, but we still do it for demo purposes. First, we will create a dictionary that is part of the registered types. Then we will create a DataTable, but unlike when using the method RegisterDefaultAliasSafe, this time, the code will successfully work as the DataTable is part of the types registered this time.

// Global Context: EvalManager.DefaultContext.RegisterDefaultAliasSafe();

var context = new EvalContext();
context.UnregisterAll();
context.RegisterDefaultAliasUnsafe();

// 1 - You can access the Dictionary object since the type has been registered in the RegisterDefaultAliasSafe
var r1 = context.Execute<int>(@"var dict = new Dictionary<string, object>(); return dict.Count;");

Console.WriteLine("1 - Result: " + r1);

// 1 - You can access the DataTable object with the method `RegisterDefaultAliasUnsafe` unlike the method `RegisterDefaultAliasSafe`
var r2 = context.Execute<int>(@"var dt = new DataTable(); return dt.Rows.Count;");

Console.WriteLine("2 - Result: " + r2);

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To learn more and see what contains this method, see Register Default Alias Safe/Unsafe

RegisterDomainAssemblies

The RegisterDomainAssemblies method registers all types from all assemblies loaded in the current domain. This method is only supported in the .NET Framework.

In this example, we will register all assemblies found and use our method Program.AddDemo. Keep in mind that using this method registers all types from all assemblies found, which for most scenarios is overkill, so we normally recommend only registering types or assemblies that you really need for the compilation.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterDomainAssemblies();
		
		var context = new EvalContext();
		context.RegisterDomainAssemblies();
		
		var r1 = context.Execute<int>("Program.AddDemo(x, y)", new { x = 1, y = 2 });
		Console.WriteLine("1 - Result: " + r1);
	}
	
	public static int AddDemo(int x, int y)
	{
		return x + y;
	}
}

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RegisterExtensionMethod

The RegisterExtensionMethod method registers all extension methods from the types or method list provided.

In this example, we will register an extension method and use it. Then we will check if the extension method was registered with the IsRegisteredExtensionMethod method, unregister it with the method UnregisterExtensionMethod and verify that the method was correctly unregistered.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterExtensionMethods(typeof(Extensions));
		
		var context = new EvalContext();
		context.RegisterExtensionMethod(typeof(Extensions));
		
		var r1 = context.Execute<int>("x.AddDemo(y)", new { x = 1, y = 2 });
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if the extension methods is registered
		var r2 = context.IsRegisteredExtensionMethod(typeof(Extensions));
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister the extension methods
		context.UnregisterExtensionMethod(typeof(Extensions));
		
		// Check if the extension methods have been successfully unregistered
		var r3 = context.IsRegisteredExtensionMethod(typeof(Extensions));
		Console.WriteLine("3 - Result: " + r3);
	}
}

public static class Extensions
{
	public static int AddDemo(this int x, int y)
	{
		return x + y;
	}
}

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RegisterGlobalConstant

The RegisterGlobalConstant method registers a global constant value. The constant value is shared across all evaluations but cannot be modified (not writable).

In this example, we will first register the constant 'x' with the value equal to 1. First, we will execute a simple addition expression that will work. Then, we will try to assign a new value to our constant 'x', which will fail since a constant is not writable. Finally, we will use the IsRegisteredGlobalConstant and UnregisterGlobalConstant methods to show the constant was registered and successfully unregistered.

// Global Context: EvalManager.DefaultContext.RegisterGlobalConstant("x", 1)

var context = new EvalContext();
context.RegisterGlobalConstant("x", 1);

var r1 = context.Execute<int>("x + y", new { y = 2 });
Console.WriteLine("1 - Result: " + r1);

try
{
	// Try to change the constant value
	var fail = context.Execute("x = 2; return x;");
}
catch(Exception ex)
{
	Console.WriteLine("2 - Exception: " + ex.Message);
}

// Check if the constant "x" is registered
var r3 = context.IsRegisteredGlobalConstant("x");
Console.WriteLine("3 - Result: " + r3);

// Unregister the constant "x"
context.UnregisterGlobalConstant("x");

// Check if the constant "x" has been successfully unregistered
var r4 = context.IsRegisteredGlobalConstant("x");
Console.WriteLine("4 - Result: " + r4);

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NOTE: A global constant has the same behavior as creating a constant in the code, such as public const int x = 1;. You can use the constant value, but you cannot change the value. However, like a const you can still add/remove items from a list or change the property values of an entity but not re-assign a new entity itself.

RegisterGlobalVariable

The RegisterGlobalVariable method registers a global variable value. This variable value is shared across all evaluations and can be modified.

In this example, we will register a global variable. In the first expression, we will increment the value of the global variable and return it. In the second expression, we will return the value of the global variable and notice that it's the same value as the previous one since the variable is shared across all expressions. Lastly, we will check using IsRegisteredGlobalVariable and UnregisterGlobalVariable methods that the global variable was successfully registered and unregistered.

// Global Context: EvalManager.DefaultContext.RegisterGlobalVariable("x", 1);

var context = new EvalContext();
context.RegisterGlobalVariable("x", 1);

var r1 = context.Execute<int>("x++; return x"); // return 2
Console.WriteLine("1 - Result: " + r1);

var r2 = context.Execute<int>("return x"); // return 2
Console.WriteLine("2 - Result: " + r2);

// Check if the global variable "x" is registered
var r3 = context.IsRegisteredGlobalVariable("x"); // return true
Console.WriteLine("3 - Result: " + r3);

// Unregister the global variable "x"
context.UnregisterGlobalVariable("x");

// Check if the global variable "x" has been successfully unregistered
var r4 = context.IsRegisteredGlobalVariable("x"); // return false
Console.WriteLine("4 - Result: " + r4);

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NOTE: A global variable has the same behavior as creating a static variable in the code, such as public static int x = 1;. The variable is readable and writable, so when changing the value, all codes accessing this variable also now have the modified value.

RegisterKeyword

The RegisterKeyword method registers a keyword for the specified extension methods. For example, if you register the keyword "isin" for the extension method "IsIn", you can now create an expression such as "x isin list".

In this example, we will first create and register an extension method, then register the keyword "isin" that we can now use to call the IsIn extension methods directly. In the first expression, 2 isin list, we will show an example of how the keyword can be used. Then we will check if the keyword was successfully registered and unregistered with the IsRegisteredKeyword and UnregisterKeyword methods.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterKeyword("isin", "IsIn");
		
		var context = new EvalContext();
		context.RegisterExtensionMethod(typeof(CustomExtensions));;
		context.RegisterKeyword("isin", "IsIn");
		
		var list = new List<int>() { 1, 2, 3 };
		
		var r1 = context.Execute<bool>("2 isin list", new { list });
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if the keyword "isin" is registered
		var r2 = context.IsRegisteredKeyword("isin"); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister the keyword "isin"
		context.UnregisterKeyword("isin");
		
		// Check if the keyword "isin" has been successfully unregistered
		var r3 = context.IsRegisteredKeyword("isin"); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
}

public static class CustomExtensions
{
	public static bool IsIn<T>(this T x, List<T> list)
	{
		return list.Contains(x);
	}
}

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RegisterLocalVariable

The RegisterLocalVariable method registers a local variable value. This variable value is not shared across all evaluations and can be modified. In other words, the value is only modified for the current evaluation and doesn't impact the other evaluations.

In this example, we will register a global variable. In the first expression, we will increment the value of the global variable and return it. In the second expression, we will return the value of the global variable and notice that the value is still 1. That's because, unlike the global variable, the local variable value scope is only for the current expression. Lastly, we will check using IsRegisteredLocalVariable and UnregisterLocalVariable methods that the global variable was successfully registered and unregistered.

// Global Context: EvalManager.DefaultContext.RegisterLocalVariable("x", 1);

var context = new EvalContext();
context.RegisterLocalVariable("x", 1);

var r1 = context.Execute<int>("x++; return x"); // return 2
Console.WriteLine("1 - Result: " + r1);

var r2 = context.Execute<int>("return x"); // return 1
Console.WriteLine("2 - Result: " + r2);

// Check if the local variable "x" is registered
var r3 = context.IsRegisteredLocalVariable("x"); // return true
Console.WriteLine("3 - Result: " + r3);

// Unregister the local variable "x"
context.UnregisterLocalVariable("x");

// Check if the local variable "x" has been successfully unregistered
var r4 = context.IsRegisteredLocalVariable("x"); // return false
Console.WriteLine("4 - Result: " + r4);

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NOTE: A local variable has the same behavior as passing a variable in a parameter to a method. Whenever you change the variable's value in the method, the value used to call the method is not modified. However, if you pass an object such as a List and Add an item, the list used when calling the method is also modified.

RegisterMember

The RegisterMember method registers all instance members from the types or fields list provided. A member is a Property, Field, Method, or Constructor.

In this example, we will first set our context in safe mode with context.SafeMode = true; and unregister all current types with context.UnregisterAll();. We need to set SafeMode = true as; otherwise, members such as methods will be automatically accessible. In the first expression, we will try to access the GetCustomerID method, which will fail since we are in SafeMode, and then we will register the member and try again, which this time will success. To finish, we will use our methods IsRegisteredMember and UnregisterMember to unregister all methods from our Customer type and make sure it has been successfully unregistered.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterMember(typeof(Customer));
		
		var context = new EvalContext();
		context.SafeMode = true;
		context.UnregisterAll();		
		
		var customer = new Customer() { CustomerID = 1 };
		
		try
		{
			var fail = context.Execute<int>("GetCustomerID()", customer);
		}
		catch(Exception ex)
		{
			Console.WriteLine("1 - Exception: " + ex.Message);
		}
		
		context.RegisterMember(typeof(Customer));		
		
		var r2 = context.Execute<int>("GetCustomerID()", customer);
		Console.WriteLine("2 - Result: " + r2);
		
		// Check if all members of the type `Customer` is registered
		var r3 = context.IsRegisteredMember(typeof(Customer)); // return true
		Console.WriteLine("3 - Result: " + r3);
		
		// Unregister all members of the type `Customer`
		context.UnregisterMember(typeof(Customer));
		
		// Check if all members of the type `Customer` has been successfully unregistered
		var r4 = context.IsRegisteredMember(typeof(Customer)); // return false
		Console.WriteLine("4 - Result: " + r4);
	}
	
	public class Customer
	{
		public int CustomerID { get; set; }
		
		public int GetCustomerID()
		{
			return CustomerID;
		}
	}
}

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RegisterNamespace

The RegisterNamespace method registers all types in the specified assembly under the specified namespaces.

In this example, we will register all members of the namespace Z2. In the first expression, we will try to create a new instance of the Z1.Customer1, which will fail since members under the namespace Z1 has not been registered. In the second expression, we will successfully create a new instance of the Z2.Customer2 customer, as we initially registered all members under the Z2 namespace. To complete our example, we will use the methods IsRegisteredNamespace and UnregisterNamespace to check if all members have been registered and unregister members under this namespace.

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterMember(typeof(Customer));
		
		var context = new EvalContext();
		context.RegisterNamespace(typeof(Program).Assembly, "Z2");	
		
		try
		{
			var fail = context.Execute<int>("new Customer1();");
		}
		catch(Exception ex)
		{
			Console.WriteLine("1 - Exception: " + ex.Message);
		}	
		
		var r2 = context.Execute("new Customer2();");
		Console.WriteLine("2 - Result: " + r2);
		
		// Check if all members of the namespace "Z" is registered
		var r3 = context.IsRegisteredNamespace(typeof(Program).Assembly, "Z2"); // return true
		Console.WriteLine("3 - Result: " + r3);
		
		// Unregister all members of the namespace "Z"
		context.UnregisterNamespace(typeof(Program).Assembly, "Z2");
		
		// Check if all members of the namespace "Z" has been successfully unregistered
		var r4 = context.IsRegisteredNamespace(typeof(Program).Assembly, "Z2"); // return false
		Console.WriteLine("4 - Result: " + r4);
	}
}

namespace Z1
{
	public class Customer1
	{
		public int CustomerID { get; set; }
	}
}

namespace Z2
{	
	public class Customer2
	{
		public int CustomerID { get; set; }
	}
}

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RegisterStaticField

The RegisterStaticField method registers all static fields from the types or fields list provided.

In this example, we will register all static fields of the type Program with the method RegisterStaticField and then use it in our expressions. Then we will demonstrate how to use the method IsRegisteredStaticField and UnregisterStaticField to check if all statics fields are currently registered and to unregister them.

using System;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterStaticField(typeof(Program));
		
		var context = new EvalContext();
		context.RegisterStaticField(typeof(Program));		
		
		var r1 = context.Execute<int>("MyStaticField + 100"); // return 101
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if all static fields of the type `Program` is registered
		var r2 = context.IsRegisteredStaticField(typeof(Program)); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister all static fields of the type `Program`
		context.UnregisterStaticField(typeof(Program));
		
		// Check if all static fields of the type `Program` has been successfully unregistered
		var r3 = context.IsRegisteredStaticField(typeof(Program)); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
	
	public static int MyStaticField = 1;
}

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RegisterStaticMember

The RegisterStaticMember method registers all static members from the types or members list provided. A member is a Property, Field or Method.

In this example, we will register all static fields, properties, and methods of the type Program with the method RegisterStaticMember and then use it in our expressions. Then we will demonstrate how to use the method IsRegisteredStaticMember and UnregisterStaticMember to check if all statics members are currently registered and to unregister them.

using System;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterStaticMember(typeof(Program));
		
		var context = new EvalContext();
		context.RegisterStaticMember(typeof(Program));		
		
		var r1 = context.Execute<int>("MyStaticField + MyStaticProperty + MyStaticMethod()"); // return 6
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if all static members of the type `Program` is registered
		var r2 = context.IsRegisteredStaticMember(typeof(Program)); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister all static members of the type `Program`
		context.UnregisterStaticMember(typeof(Program));
		
		// Check if all static members of the type `Program` has been successfully unregistered
		var r3 = context.IsRegisteredStaticMember(typeof(Program)); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
	
	public static int MyStaticField = 1;
	public static int MyStaticProperty { get; set; } = 2;
	public static int MyStaticMethod()
	{
		return 3;
	}
}

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RegisterStaticMethod

The RegisterStaticMethod method registers all static methods from the types or fields list provided.

In this example, we will register all static methods of the type Program with the method RegisterStaticMethod and then use it in our expressions. Then we will demonstrate how to use the method IsRegisteredStaticMethod and UnregisterStaticMethod to check if all statics methods are currently registered and to unregister them.

using System;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterStaticMethod(typeof(Program));
		
		var context = new EvalContext();
		context.RegisterStaticMethod(typeof(Program));		
		
		var r1 = context.Execute<int>("MyStaticMethod() + 100"); // return 103
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if all static methods of the type `Program` is registered
		var r2 = context.IsRegisteredStaticMethod(typeof(Program)); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister all static methods of the type `Program`
		context.UnregisterStaticMethod(typeof(Program));
		
		// Check if all static methods of the type `Program` has been successfully unregistered
		var r3 = context.IsRegisteredStaticMethod(typeof(Program)); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
	
	public static int MyStaticMethod()
	{
		return 3;
	}
}

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RegisterStaticProperty

The RegisterStaticProperty method registers all static properties from the types or properties list provided.

In this example, we will register all static properties of the type Program with the method RegisterStaticProperty and then use it in our expressions. Then we will demonstrate how to use the method IsRegisteredStaticProperty and UnregisterStaticProperty to check if all statics properties are currently registered and to unregister them.

using System;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterStaticProperty(typeof(Program));
		
		var context = new EvalContext();
		context.RegisterStaticProperty(typeof(Program));		
		
		var r1 = context.Execute<int>("MyStaticProperty + 100"); // return 102
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if all static properties of the type `Program` is registered
		var r2 = context.IsRegisteredStaticProperty(typeof(Program)); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister all static properties of the type `Program`
		context.UnregisterStaticProperty(typeof(Program));
		
		// Check if all static properties of the type `Program` has been successfully unregistered
		var r3 = context.IsRegisteredStaticProperty(typeof(Program)); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
	
	public static int MyStaticProperty { get; set; } = 2;
}

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RegisterType

The RegisterType method registers all types provided. The method also registers extension methods from types but doesn't register other static members. For example, if you register the type "Z.MyNamespace.MyClass", you can now create an expression such as "new MyClass()" or any extension methods from this type.

In this example, we will register the type MyClassHelper and the type MyExtensions to register his extension methods. In the first expression, we will use our class and our extension methods with a simple arithmetic operation. Then we will demonstrate how to use the method IsRegisteredType and UnregisterType with our MyClassHelper to validate if the type is currently registered and to unregister it.

using System;
using System.Collections.Generic;
using Z.Expressions;

public class Program
{
	public static void Main()
	{
		// Global Context: EvalManager.DefaultContext.RegisterType(typeof(Helper));
		
		var context = new EvalContext();
		context.RegisterType(typeof(MyClassHelper));
		context.RegisterType(typeof(MyExtensions));
		
		var r1 = context.Execute<int>("new MyClassHelper().MyClassHelperID + 2.AddMe(3)"); // return 6
		Console.WriteLine("1 - Result: " + r1);
		
		// Check if the type `MyClassHelper` is registered
		var r2 = context.IsRegisteredType(typeof(MyClassHelper)); // return true
		Console.WriteLine("2 - Result: " + r2);
		
		// Unregister the type `MyClassHelper`
		context.UnregisterType(typeof(MyClassHelper));
		
		// Check the type `MyClassHelper` has been successfully unregistered
		var r3 = context.IsRegisteredType(typeof(MyClassHelper)); // return false
		Console.WriteLine("3 - Result: " + r3);
	}
	
	public class MyClassHelper
	{
		public int MyClassHelperID { get; set; } = 1;
	}
}

public static class MyExtensions
{	
	public static int AddMe(this int x, int y)
	{
		return x + y;
	}
}

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Last updated: 2025-07-04
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