Check out example codes for "c# create dll runtime". It will help you in understanding the concepts better.

Code Example 1

using System.CodeDom.Compiler;
using System.Diagnostics;
using Microsoft.CSharp;

CSharpCodeProvider codeProvider = new CSharpCodeProvider();
ICodeCompiler icc = codeProvider.CreateCompiler();
System.CodeDom.Compiler.CompilerParameters parameters = new CompilerParameters();
parameters.GenerateExecutable = false;
parameters.OutputAssembly = "AutoGen.dll";
CompilerResults results = icc.CompileAssemblyFromSource(parameters, yourCodeAsString);

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