Writing an IME that works correctly with an Edit Control
4/8/2010
When you create an input method editor (IME), or when you port an IME between Windows Mobile Standard and Windows Mobile Classic, you may have to customize the HKEY_LOCAL_MACHINE\SYSTEM\Ime\Settings registry key to get the desired behavior in edit controls. This is particularly likely in use cases such as focus switching, and ensuring that the final character input into a password edit control is included in the composition string.
The HKEY_LOCAL_MACHINE\SYSTEM\Ime\Settings registry key is used to determine the behavior of an IME. The Settings key's value represents the following structure, where the first member is the lowest bit.
struct {
bool m_CompositionStringGetExcluded:1;
bool m_CompositionStringSetExcluded:1;
bool m_DetermineOnLossOfFocus:1;
bool m_CandidateOnKeyUp:1;
bool m_UnderlineCompositionString:1;
bool m_CancelOnBufferFull:1;
};
The following table describes the role of each of the structure's members.
| Value : type | Description |
|---|---|
m_CompositionStringGetExcluded |
Default setting is 1. Indicates whether the composition string (undetermined string) is excluded when the user attempts to get the text from the edit control. |
m_CompositionStringSetExcluded |
Default setting is 1. Determines whether the composition string is excluded when the user attempts to set the text for the edit control. |
m_DetermineOnLossOfFocus |
Default setting is 1. Determines if the the composition string is finalized when thes edit control loses focus. |
m_CandidateOnKeyUp |
Default setting is 1. Specifies whether to show the candidate window on key up. |
m_UnderlineCompositionString |
Default setting is 1. Specifies whether to draw an underline for the composition string. |
m_CancelOnBufferFull |
Default setting is 1. Determines whether to cancel the composition string when the buffer is full. |