How to use complied type in another compile class using CodeDOM?

I'm use CodeDOM to compile class in run time.

First generate Invoice class

string code1 = @"using System;
                            namespace CodeDOM
                            {
                             public class Invoice
                             {
                              public string InvoiceNo{ get; set; }
                              public DateTime Date{ get; set; }
                              public double Value{ get; set; }
                             }
                            }"; 
CSharpCodeProvider provider = new CSharpCodeProvider();
CompilerParameters parameters = new CompilerParameters();          
parameters.GenerateInMemory = true;
parameters.GenerateExecutable = false;
CompilerResults results = provider.CompileAssemblyFromSource(parameters, code1);

After that compile another class.This calss use Invoice class.

string code2 = @"using System;
                             namespace CodeDOM
                            {
                             public class DataInjector
                             {
                              public void Insert( CodeDOM.Invoice obj ){ 

                              }
                             }
                            }";
CSharpCodeProvider provider1 = new CSharpCodeProvider();
CompilerParameters parameters1 = new CompilerParameters();
parameters1.GenerateInMemory = false;
parameters1.GenerateExecutable = false;
CompilerResults results1 = provider1.CompileAssemblyFromSource(parameters1, code2);

Final results1 show error "The type or namespace name 'Invoice' does not exist in the namespace 'CodeDOM' (are you missing an assembly reference?)"

Why we cant use Invoice class?