c# 动态扩展类型 示例源码

【核心代码】

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

 

class sample

{

        protected Type BuildExtendType(Type sourceType, PropertyInfo[] extenders)
        {
            StringBuilder codeBuilder = new StringBuilder();
            CodeDomProvider comp = new  CSharpCodeProvider();
            CompilerParameters cp = new CompilerParameters();
            codeBuilder.Append("using System;");
            codeBuilder.Append("using Microsoft.JScript;");
            codeBuilder.Append("public class ExtendObject{");
            codeBuilder.Append(PrepareProperties(sourceType.GetProperties()));
            codeBuilder.Append(PrepareMappingProperties(extenders));
            codeBuilder.Append("}");
            cp.ReferencedAssemblies.Contains("System.dll");
            cp.ReferencedAssemblies.Add("Microsoft.JScript.dll");  
            cp.GenerateExecutable = false;
            cp.GenerateInMemory = true;
            string code = codeBuilder.ToString();
            CompilerResults cr = comp.CompileAssemblyFromSource(cp, code);
            if (cr.Errors.HasErrors)
            {
                string description = string.Empty;
                foreach (CompilerError e in cr.Errors)
                {
                    description  = e.ErrorText;
                }
                throw new Exception(description);
            }
            else
            {
                Assembly a = cr.CompiledAssembly;
                return a.GetType("ExtendObject");
            }
        }

        protected string PrepareProperties(PropertyInfo[] ps)
        {
            StringBuilder sProperties = new StringBuilder();
            foreach (PropertyInfo p in ps)
            {
                sProperties.Append("protected ");
                sProperties.Append(p.PropertyType.FullName);
                sProperties.Append(" ");
                sProperties.Append("_"   p.Name);
                sProperties.Append(";");

                sProperties.Append("public ");
                sProperties.Append(p.PropertyType.FullName);
                sProperties.Append(" ");
                sProperties.Append(p.Name);
                sProperties.Append("{get{return "   "_"   p.Name   ";}set{"   "_"   p.Name   "= value;}}");
            }
            return sProperties.ToString();            
          }

          protected string PrepareMappingProperties(PropertyInfo[] ps)
        {
            //Samples: ITAB_BILL_TEMP_NAME
            StringBuilder sProperties = new StringBuilder();
            foreach (PropertyInfo p in ps)
            {
                sProperties.Append("protected ");
                sProperties.Append(p.PropertyType.FullName);
                sProperties.Append(" ");
                sProperties.Append("_"   p.DeclaringType.Name.Substring(11)   "_"   p.Name);
                sProperties.Append(";");

                sProperties.Append("public ");
                sProperties.Append(p.PropertyType.FullName);
                sProperties.Append(" ");
                sProperties.Append(p.DeclaringType.Name.Substring(11)   "_"   p.Name);
                sProperties.Append("{get{return "   "_"   p.DeclaringType.Name.Substring(11)   "_"   p.Name   ";}set{"   "_"   p.DeclaringType.Name.Substring(11)   "_"   p.Name   " = value;}}");
            }
            return sProperties.ToString();
        }

}