Execute code lines from a text file in C#

Question

I have a text file looks like:

AssembleComponent Motor = new AssembleComponent;
AssembleComponent Shaft = new AssembleComponent;
......

Motor.cost = 100;
Motor.quantity = 100;
Shaft.cost = 10;
Shaft.quantity = 100;
......

I wish to execute these code lines in C#, so that I will have these Motor.cost, Motor.quantity, Shaft.cost, Shaft.quantity variables stored in the memory for later calculation.

What can I do to achieve this?

Answer 1

Store it as XML instead

<?xml version="1.0" encoding="UTF-8"?>
<Components>
    <Component name="Motor" cost="100" quantity="100" />
    <Component name="Shaft" cost="10" quantity="100" />
</Components>

Assuming that you have this definition

public class AssembleComponent
{
    public decimal Cost { get; set; }
    public int Quantity { get; set; }
}

Load it like this

var components = new Dictionary<string, AssembleComponent>();
XDocument doc = XDocument.Load(@"C:\Users\Oli\Desktop\components.xml");
foreach (XElement el in doc.Root.Descendants()) {
    string name = el.Attribute("name").Value;
    decimal cost = Decimal.Parse(el.Attribute("cost").Value);
    int quantity = Int32.Parse(el.Attribute("quantity").Value);
    components.Add(name, new AssembleComponent{ 
                             Cost = cost, Quantity = quantity
                         });
}

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You can then access the components like this

AssembleComponent motor = components["Motor"];
AssembleComponent shaft = components["Shaft"];

Note: Creating the variable names dynamically by calling the compiler at runtime is not very useful since you need to know them at compile-time (or design-time if you prefer) to do something useful with them. Therefore, I added the components to a dictionary. This is a good way of creating "variables" dynamically.

Answer 2

You can use Microsoft.CSharp.CSharpCodeProvider to compile code on-the-fly.

Specifically, take a look at CompileAssemblyFromFile .

Answer 3

If it's just about data don't use a flat textfile but XML-instead.

You can deserialize the XML in to objects and perform the necessary actions on them.

Answer 4

Here's some code that I've used in the past, that does most of what you want though you may need to adapt it to your specific needs. In a nutshell, it does the following:

• Create a temporary namespace and a public static method in that namespace.
• Compile the code to an in-memory assembly.
• Extract the compiled method and turn it into a delegate.
• Execute the delegate.

At that point it's like executing a normal static method, so when you say you want the results in memory for later use, you'd have to figure out how that would work.

public void CompileAndExecute(string CodeBody)
{
    // Create the compile unit
    CodeCompileUnit ccu = CreateCode(CodeBody);

    // Compile the code 
    CompilerParameters comp_params = new CompilerParameters();
    comp_params.GenerateExecutable = false;
    comp_params.GenerateInMemory = true;
    comp_params.TreatWarningsAsErrors = true;
    comp_results = code_provider.CompileAssemblyFromDom(comp_params, ccu);

    // CHECK COMPILATION RESULTS
    if (!comp_results.Errors.HasErrors)
    {
        Type output_class_type = comp_results.CompiledAssembly.GetType("TestNamespace.TestClass");

        if (output_class_type != null)    
        {    
            MethodInfo compiled_method = output_class_type.GetMethod("TestMethod", BindingFlags.Static | BindingFlags.Public);    
            if (compiled_method != null)    
            {    
                Delgate created_delegate = Delegate.CreateDelegate(typeof(System.Windows.Forms.MethodInvoker), compiled_method);
                if (created_delegate != null)
                {
                    // Run the code
                    created_delegate.DynamicInvoke();
                }
            }
        }
    }
    else
    {
        foreach (CompilerError error in comp_results.Errors)
        {
            // report the error
        }
    }
}

public CodeCompileUnit CreateCode(string CodeBody)
{
    CodeNamespace code_namespace = new CodeNamespace("TestNamespace");

    // add the class to the namespace, add using statements
    CodeTypeDeclaration code_class = new CodeTypeDeclaration("TestClass");
    code_namespace.Types.Add(code_class);
    code_namespace.Imports.Add(new CodeNamespaceImport("System"));

    // set function details
    CodeMemberMethod method = new CodeMemberMethod();
    method.Attributes = MemberAttributes.Public | MemberAttributes.Static;
    method.ReturnType = new CodeTypeReference(typeof(void));
    method.Name = "TestMethod";

    // add the user typed code
    method.Statements.Add(new CodeSnippetExpression(CodeBody));

    // add the method to the class
    code_class.Members.Add(method);

    // create a CodeCompileUnit to pass to our compiler
    CodeCompileUnit ccu = new CodeCompileUnit();
    ccu.Namespaces.Add(code_namespace);

    return ccu;
}

Answer 5

You have two main options:

1. Expand the text until it becomes valid C# code, compile it and execute it
2. Parse it and execute it yourself (ie interpret it).

Answer 6

This can be done following these steps: CodeGeneration => InMemory Compilation to Exe ==> Execution .

You can design the construct similar to this:

public bool RunMain(string code)
{
    const string CODE_NAMESPACE = "CompileOnFly";
    const string CODE_CLASS = "Program";
    const string CODE_METHOD = "Main";

    try
    {
        var code_namespace = new CodeNamespace(CODE_NAMESPACE);

        // add the class to the namespace, add using statements
        var  code_class = new CodeTypeDeclaration(CODE_CLASS);
        code_namespace.Types.Add(code_class);
        code_namespace.Imports.Add(new CodeNamespaceImport("System"));

        // set function details
        var method = new CodeMemberMethod();
        method.Attributes = MemberAttributes.Public | MemberAttributes.Static;
        method.ReturnType = new CodeTypeReference(typeof(void));
        method.Name = CODE_METHOD;

        // add the user typed code
        method.Statements.Add(new CodeSnippetExpression(code));

        // add the method to the class
        code_class.Members.Add(method);

        // create a CodeCompileUnit to pass to our compiler
        CodeCompileUnit code_compileUnit = new CodeCompileUnit();
        code_compileUnit.Namespaces.Add(code_namespace);


        var compilerParameters = new CompilerParameters();
        compilerParameters.ReferencedAssemblies.Add("system.dll");
        compilerParameters.GenerateExecutable = true;
        compilerParameters.GenerateInMemory = true;
        compilerParameters.TreatWarningsAsErrors = true;

        var code_provider = CodeDomProvider.CreateProvider("CSharp");
        var comp_results = code_provider.CompileAssemblyFromDom(compilerParameters, code_compileUnit);

        if (comp_results.Errors.HasErrors)
        {
            StringBuilder sb = new StringBuilder();
            foreach (CompilerError error in comp_results.Errors)
            {
                sb.AppendLine(String.Format("Error ({0}): {1}", error.ErrorNumber, error.ErrorText));
            }

                   
            throw new InvalidOperationException(sb.ToString());
        }

        //Get assembly, type and the Main method:
        Assembly assembly = comp_results.CompiledAssembly;
        Type program = assembly.GetType($"{CODE_NAMESPACE}.{CODE_CLASS}");
        MethodInfo main = program.GetMethod(CODE_METHOD);

        //runtit
        main.Invoke(null, null);
        return true;

    }
    catch(Exception compileException)
    {
        Console.Write(compileException.ToString());
        return false;
    }
} 

In the code above we are actually creating a simple console Program.Main() as

namespace CompileOnFly
{
    internal class Program
    {
       static void Main()
        {
            //<your code here>  
        }
    }
}

in memory then compiling it as executable in Memory and executing it. But the Main() body //<your code here> is added dynamically with the parameter code to the method.

So If you have a script in the text file script.txt as this:

Console.Write("Write your name: ");
var name = Console.ReadLine();
Console.WriteLine("Happy new year 2023 " + name);

You can simply read all the text and send it as parameter to it:

 var code = File.ReadAllText(@"script.txt");
 RunMain(code);

To run the statements in the script.txt file.

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