EditTable Cookbook - Trapping the ENTER key

A recent question on the Revelation Forum asked how to detect an ENTER keypress when using an EditTable as this is not exposed by the standard OpenInsight CHAR event (ENTER is one of the keys that the EditTable normally considers to be "reserved" like TAB and the Arrow keys).

Despite this limitation it is actually possible to detect an ENTER keypress with WM_KEYDOWN window message and the WINMSG event but ONLY if the EditTable is set to "Protected", i.e.

To trap the ENTER key we first need to tell OpenInsight that we want to be notified of any WM_KEYDOWN window messages that are sent to the EditTable by using the OpenInsight QUALIFY_EVENT message. This is normally done in the form's CREATE event:

0001     $insert winAPI_WindowMessage_Equates 0002     $insert logical 0003      0004     call send_Message( @window : ".TABLE_1", "QUALIFY_EVENT", | 0005                        WM_KEYDOWN$, TRUE$ ) 0006     

Once we've done this we can write a WINMSG event handler for the EditTable that responds to the VK_RETURN keycode:

0001  /* 0002     Example WINMSG event handler to trap the Enter key (VK_RETURN$) 0003     while processing the WM_KEYDOWN$ window message. 0004         0005        hwnd    → handle of the EditTable 0006        message → Message number - should be WM_KEYDOWN$ 0007        wParam  → Virtual Keycode - we are looking for VK_RETURN$ 0008        lParam  → Keydown flags - see MSDN for more info! 0009         0010  */ 0011      0012     $insert winAPI_WindowMessage_Equates 0013     $insert winAPI_VirtualKey_Equates 0014     $insert logical 0015      0016     begin case 0017        case ( message = WM_KEYDOWN$ ) 0018         0019           begin case 0020              case ( wParam = VK_RETURN$ ) 0021                 // Write your code to handle the event here 0022                 call msg( @window, "Enter key pressed!" ) 0023                  0024           end case 0025            0026     end case 0027      0028  return TRUE$

(Note in these examples we are using some insert records from our WinAPI Library that you can find here)

Captain C

Where Can I find the equates winAPI_WindowMessage_Equates and winAPIVirtualKey_Equates? It is not in my sysprocs.

Thanks

Hello Anonymous,

They can be found the in the WinAPI library (mentioned at the end of the article :) here:

http://sprezzblog.blogspot.com/2010/06/sprezzatura-windows-api-library.html

It's a standard RDK - if you install it you'll find the inserts mentioned above and a whole load of other useful ones too.