public bool SetNewParameterToTypeWall(UIApplication app, DefinitionFile myDefinitionFile)
{
    // Create a new group in the shared parameters file
    DefinitionGroups myGroups = myDefinitionFile.Groups;
    DefinitionGroup myGroup = myGroups.Create("MyParameters");

    // Create a type definition
    ExternalDefinitionCreationOptions option = new ExternalDefinitionCreationOptions("CompanyName", SpecTypeId.String.Text);
    Definition myDefinition_CompanyName = myGroup.Definitions.Create(option);

    // Create a category set and insert category of wall to it
    CategorySet myCategories = app.Application.Create.NewCategorySet();
    // Use BuiltInCategory to get category of wall
    Category myCategory = Category.GetCategory(app.ActiveUIDocument.Document, BuiltInCategory.OST_Walls);

    myCategories.Insert(myCategory);

    //Create an object of TypeBinding according to the Categories
    TypeBinding typeBinding = app.Application.Create.NewTypeBinding(myCategories);

    // Get the BingdingMap of current document.
    BindingMap bindingMap = app.ActiveUIDocument.Document.ParameterBindings;

    // Bind the definitions to the document
    bool typeBindOK = bindingMap.Insert(myDefinition_CompanyName, typeBinding,
      GroupTypeId.Text);
    return typeBindOK;
}

Public Function SetNewParameterToTypeWall(app As UIApplication, myDefinitionFile As DefinitionFile) As Boolean
   ' Create a new group in the shared parameters file
   Dim myGroups As DefinitionGroups = myDefinitionFile.Groups
   Dim myGroup As DefinitionGroup = myGroups.Create("MyParameters")

   ' Create a type definition
   Dim [option] As New ExternalDefinitionCreationOptions("CompanyName", SpecTypeId.String.Text)
   Dim myDefinition_CompanyName As Definition = myGroup.Definitions.Create([option])

   ' Create a category set and insert category of wall to it
   Dim myCategories As CategorySet = app.Application.Create.NewCategorySet()
   ' Use BuiltInCategory to get category of wall
   Dim myCategory As Category = Category.GetCategory(app.ActiveUIDocument.Document, BuiltInCategory.OST_Walls)

   myCategories.Insert(myCategory)

   'Create an object of TypeBinding according to the Categories
   Dim typeBinding As TypeBinding = app.Application.Create.NewTypeBinding(myCategories)

   ' Get the BingdingMap of current document.
   Dim bindingMap As BindingMap = app.ActiveUIDocument.Document.ParameterBindings

      ' Bind the definitions to the document
      Dim typeBindOK As Boolean = bindingMap.Insert(myDefinition_CompanyName, typeBinding, GroupTypeId.Text)
      Return typeBindOK
End Function