What is the CodeDOM
The CodeDOM is an API that gives you the ability to create a programming structure of
namespaces, objects, and programming constructs by adding items to different collections.
All CodeDOM programs start out with the creation of a
ICodeGenerator for the target
language. The following code shows the creation of the
ICodeGenerator for C#.
ICodeGenerator cg =new CSharpCodeProvider().CreateGenerator();
...
CSharpCodeProvider cdp = new CSharpCodeProvider();
cg = cdp.CreateGenerator();
C#
The
ICodeGenerator is used to generate the actual code once a CodeDOM tree is built. To begin building your tree, you need to start with a
CodeNamespace object. This object
will contain any types and import directives. With the
CodeNamespace object you can
begin the tree. For the following sample, several
CodeNamespaceImport objects
are used to generate import directives for commonly used namespaces. The sample also
needs to generate a class construct so by using a
CodeTypeDeclaration and setting the
IsClass property to true. The following code demonstrates these concepts.
CodeNamespace cnamespace = new CodeNamespace("Microsoft.Samples");
cnamespace.Imports.Add (new CodeNamespaceImport ("System") );
...
CodeTypeDeclaration co = new CodeTypeDeclaration (typeName +"List");
co.IsClass = true;
cnamespace.Types.Add (co);
C#
At the end of the previous example, the class type definition is added
to the
Types collection of the
CodeNamespace object. This is how a CodeDOM
tree is built. Starting with a
CodeNamespace object and working down through classes
to class members. Class members in turn contain different types of code statements
and expressions. Once the entire tree is built, the entire source tree can be written
with a call to
GenerateCodeFromNamespace, a method on
ICodeGenerator.
The method is being passed the
CodeNamespace object and a
TextWriter.
baseCompiler.GenerateCodeFromNamespace (cnamespace, w, null);
C#
The following sample demonstrates the techniques described above by generating
the code for a strongly typed List. It also contains additional information and code
for generating code statements and expressions that were left out of the above documentation
for brevity.