AlphaBlend – where does it come from?

Based on our experience, if a Windows CE (Windows Compact 7) device fails to draw transparent controls, it is because it is missing AlphaBlend function from its WIN API. AlphaBlend function is present in coredll.dll. During the build of the OS image the OS designer can choose, whether AlphaBlend function will be present or will not be present in the OS by setting / not-setting the SYSGEN_GDI_ALPHABLEND variable.

According to our present experience, if SYSGEN_GDI_ALPHABLEND is not set and hence AlphaBlend function is not present in the OS a SystemMissingMethodException is thrown by CLR. iPack controls catch the exception and AUTOMATICALLY switch to using AlphaBlend function located in BeeMobile.Common.dll. If BeeMobile.Common.dll is not present, the controls will throw an exception (and won’t catch it this time) to inform the developer, that the BeeMobile.Common.dll was not found.
The developer has no control over this mechanism and he cannot explicitly choose the controls to use AlphaBlend function from BeeMobile.Common.dll.