writing re-call headers

Owned by reinhard reinhard (Unlicensed)
Last updated: Jan 21, 2010Version comment
2 min read

Elements and attributes in the re-call header

As explained in the wxegen.exe overview, a re-call header specifies page-local variables for a re-call page/re-call function. A typical declaration looks like this (printed without the leading comment //):

<WxeFunction>
  <Parameter name="obj" type="Customer" />
  <ReturnValue type="Invoice" />
  <Variable name="fooBar" type="FooBar" />
</WxeFunction>

(The order of nodes is significant here.)

The meaning of this example re-call header roughly corresponds to a C# declaration like

Invoice MyFunc(Customer obj)
{
  FooBar fooBar;
  ...
}

Since angle brackets (<>) must be escaped in XML, a declaration like <ReturnValue type="ObjectList<Customer>" /> is invalid and must be re-phrased as

<ReturnValue type="ObjectList&lt;Customer&gt;" />

or, more readably (and writably):

<ReturnValue type="ObjectList{Customer}" />.

(Note the curly brackets substituting angle brackets. The mechanism is the same as in C#'s DocComments.)

More features exist, but they are rarely used. You can find the xml-schema for WXE-headers in the SVN repository

What follows is a brief discussion of those extra elements.

Understanding WxePageFunction attributes

The attributes of WxePageFunction are optional and override defaults.

attribute

overrides

example

pageType

The ASP.NET-type behind the page

EditPersonForm.cs -> EditPersonForm

aspxFile

The .aspx file with the same base name as the file the declaration is in

EditLocationForm.aspx from EditLocationForm.aspx.cs

functionName

The name of the function class that will be generated. Default is name of the page class + "Function"

EditLocationFormFunction from EditLocationForm

functionBaseType

the name passed to wxegen.exe as /baseFunction parameter

BaseFunction

As path to the aspxFile the path specified in the file mask (first) parameter to wxegen.exe is assumed, as in

 
wxegen UI\*.aspx.cs WxeFunctions.cs /prjfile:PhoneBook.Web.csproj /functionbase:...

note UI*.aspx.cs parameter

uigen.exe builds the project with the assumption that the generated files (specified in wxegen.exe's file mask parameter) shall be stored in a project sub-folder named UI.

In/out parameters for the Parameter element

The optional direction attribute for Parameter can specify whether the parameter is an in or out parameter or both:

<Parameter param1 direction="In" />
<Parameter param2 direction="Out" />
<Parameter param3 direction="InOut" />

The default is In.

Mind the usings, important note for ReSharper users

wxegen.exe copies the using s from the file with the WXE function header to wxefunctions.cs, so that all types can be resolved. However, if a type is used only in a function header, then a tool like ReSharper might deem the using statement covering the type redundant and remove it. Workaround: fully qualified type names for all types.