Implementing Model-View-Presenter in ASP.NET

/* Originaly found the code here 
 * A tool for dynamic compile and run of C# or VB.NET code
 * http://www.codeproject.com/dotnet/DynamicCompileAndRun.asp
 * By dstang2000. 
 */

using System;
using System.IO;
using System.Text;
using System.Collections;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Data;

using System.Reflection;
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using Microsoft.VisualBasic;

namespace SubSonic.CodeGenerator
{
	public class CompileEngine
	{
		public CompileEngine( string code )
		{
			this.SourceCode = code;
		}

		public CompileEngine( string code, ICodeLanguage language, string entry )
		{
			this.SourceCode = code;
			this.Language = language;
			this.EntryPoint = entry;
		}

		public void Run()
		{
			ClearErrMsgs();
            //Utilities.Utility.WriteTrace("Building Assembly");
            Assembly assembly = CreateAssembly(SourceCode);

            if (assembly == null) {
                Utilities.Utility.WriteTrace("Assembly is NULL - that means there's an error. Serving up Exception...");

                //get the error message and throw an Exception
                string sMessage = "Error generating template code: this happens because the rendering code (not that of the template) " + Environment.NewLine +
                " has encountered an error. Most likely it has to do with a Primary Key - make sure one is defined for this table." + Environment.NewLine +
                " Other possibilities revolve around reserved words and naming... Here's some more detail:" + Environment.NewLine +
                this.errMsg.ToString();

                throw new Exception(sMessage);

            } else {
                Utilities.Utility.WriteTrace("Compiling Assembly Code... Good to Go...");
                CallEntry(assembly, EntryPoint);

            }


		}

		public string OutputText;

		//Holds the main source code that will be dynamically compiled and executed
		internal string SourceCode = string.Empty;
		
		//Holds the method name that will act as the assembly entry point
		internal string EntryPoint = "Main";

		//A list of all assemblies that are referenced by the created assembly
		internal ArrayList References = new ArrayList();
	
		//A flag the determines if console window should remain open until user clicks enter
		//internal bool WaitForUserAction = true;

		//Flag that determines which languae to use
		internal ICodeLanguage Language = new CSharpCodeLanguage();

		// compile the source, and create assembly in memory
		// this method code is mainly from jconwell, 
		// see http://www.codeproject.com/dotnet/DotNetScript.asp
		private Assembly CreateAssembly(string strRealSourceCode)
		{
            if (strRealSourceCode.Length == 0)
			{
				LogErrMsgs("Error:  There was no CS script code to compile");
				return null;
			}

			//Create an instance whichever code provider that is needed
			CodeDomProvider codeProvider = Language.CreateCodeProvider();

		    //create the language specific code compiler
			//ICodeCompiler compiler = codeProvider.CreateCompiler();
            
			//add compiler parameters
			CompilerParameters compilerParams = new CompilerParameters();
			compilerParams.CompilerOptions = "/target:library"; // you can add /optimize
			compilerParams.GenerateExecutable = false;
			compilerParams.GenerateInMemory = true;			
			compilerParams.IncludeDebugInformation = true;

			// add some basic references
			compilerParams.ReferencedAssemblies.Add( "mscorlib.dll");

            compilerParams.ReferencedAssemblies.AddRange((string[])References.ToArray(typeof(string)));
			//add any aditional references needed
            //foreach (string refAssembly in References)
            //{
            //    try
            //    {
            //        string trimchar = Environment.NewLine;
            //        string trimmedref = refAssembly.Trim(trimchar.ToCharArray());
            //        trimmedref = trimmedref.Trim();
            //        if(trimmedref.Length > 0)
            //            compilerParams.ReferencedAssemblies.Add(trimmedref);
            //    }
            //    catch { }
            //}

			//actually compile the code

			CompilerResults results = codeProvider.CompileAssemblyFromSource(compilerParams, strRealSourceCode);

			//Do we have any compiler errors
			if (results.Errors.Count > 0)
			{
				foreach (CompilerError error in results.Errors)
					LogErrMsgs("Compile Error:  " + error.ErrorText );

				return null;
			}

			//get a hold of the actual assembly that was generated
			Assembly generatedAssembly = results.CompiledAssembly;

			//return the assembly
			return generatedAssembly;
		}

		// invoke the entry method
		// this method code is mainly from jconwell, 
		// see http://www.codeproject.com/dotnet/DotNetScript.asp
		private void CallEntry(Assembly assembly, string entryPoint)
		{
			try
			{
				//Use reflection to call the static Main function
				Module[] mods = assembly.GetModules(false);
				Type[] types = mods[0].GetTypes();

				foreach (Type type in types)
				{
					MethodInfo mi = type.GetMethod(entryPoint, 
							BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static);  
					if (mi != null)
					{
						if( mi.GetParameters().Length == 1 )  
						{
							if( mi.GetParameters()[0].ParameterType.IsArray )
							{
								string [] par = new string[1]; // if Main has string [] arguments
								 mi.Invoke(null, par);
							}
						}
						else
						{
							OutputText = (string)mi.Invoke(null, null);
						}
						return;
					}

				}

				
			}
			catch
			{
				//LogErrMsgs("Error:  An exception occurred", ex);	
                //throw ex;
                //if there's an error here, it's not a bad template - that would
                //be caught above. It's because the template, as designed, won't work
                //there's generally only one cause - NO PRIMARY KEY
                Utilities.Utility.WriteTrace("!!!!!!!!!! No primary key defined for this table - ####### ABORTED #######");

                //swallow it
                
			}
		}

		internal StringBuilder errMsg = new StringBuilder();
		internal void LogErrMsgs(string customMsg)
		{
			LogErrMsgs(customMsg, null);
		}

		internal void LogErrMsgs(string customMsg, Exception ex)
		{
			//put the error message into builder
            errMsg.Append("\r\n").Append(customMsg).Append(Environment.NewLine);

			//get all the exceptions and add their error messages
			while (ex != null)
			{
				errMsg.Append("\t").Append(ex.Message).Append(Environment.NewLine);	
				ex = ex.InnerException;
			}
		}

		internal void ClearErrMsgs()
		{
			errMsg.Remove( 0, errMsg.Length );
		}
	}
}