// Builds a Hello World Program Graph using System.CodeDom objects
public static CodeCompileUnit BuildHelloWorldGraph()
{            
    // Create a new CodeCompileUnit to contain the program graph
    CodeCompileUnit CompileUnit = new CodeCompileUnit();

    // Declare a new namespace object and name it
    CodeNamespace Samples = new CodeNamespace("Samples");
    // Add the namespace object to the compile unit
    CompileUnit.Namespaces.Add( Samples );

    // Add a new namespace import for the System namespace
    Samples.Imports.Add( new CodeNamespaceImport("System") );            

    // Declare a new type object and name it
    CodeTypeDeclaration Class1 = new CodeTypeDeclaration("Class1");
    // Add the new type to the namespace object's type collection
    Samples.Types.Add(Class1);            

    // Declare a new code entry point method
    CodeEntryPointMethod Start = new CodeEntryPointMethod();
    // Create a new method invoke expression
    CodeMethodInvokeExpression cs1 = new CodeMethodInvokeExpression( 
        // Call the System.Console.WriteLine method
        new CodeTypeReferenceExpression("System.Console"), "WriteLine", 
        // Pass a primitive string parameter to the WriteLine method
        new CodePrimitiveExpression("Hello World!") );
    // Add the new method code statement
    Start.Statements.Add(new CodeExpressionStatement(cs1));        

    // Add the code entry point method to the type's members collection
    Class1.Members.Add( Start );

    return CompileUnit;