Revision as of 10:20, 29 October 2013

Child Table, Grid & Column

What message is send when a DropDown column item is selected (clicked)

When an item from a column dropdown list is selected, the message SAM_AnyEdit is send to the column message actions section.

How to hide the window displayed in the taskbar when a column dropdown list is opened

When you open the dropdown list of a table column, a window is shown on the Windows taskbar.
To get rid of this window use this code under the message actions of the table column

First declare these three WinApi functions in the external functions section

Library name: USER32.DLL
   Function: FindWindowA
      Export Ordinal: 0
      Returns
         Window Handle: HWND
      Parameters
         String: LPCSTR
         String: LPCSTR

   Function: GetWindowLongA
      Export Ordinal: 0
      Returns
         Number: LONG
      Parameters
         Window Handle: HWND
         Number: INT

   Function: SetWindowLongA
      Export Ordinal: 0
      Returns
         Number: LONG
      Parameters
         Window Handle: HWND
         Number: INT
         Number: LONG

Also declare these constants

   Number: GWL_EXSTYLE      = -20
   Number: WS_EX_TOOLWINDOW = 0x80

Here the actual code for removing the window from the taskbar

On SAM_DropDown
   Set hWndDropDown = FindWindowA( "Gupta:DropDown", "" )
   If NOT hWndDropDown
      ! Maybe it is an older TD version, so search for another classname
      Set hWndDropDown = FindWindowA( ":DropDown", "" )
   If hWndDropDown
      If NOT GetWindowLongA( hWndDropDown,GWL_EXSTYLE ) & WS_EX_TOOLWINDOW
         Call SetWindowLongA( hWndDropDown, GWL_EXSTYLE, GetWindowLongA( hWndDropDown,GWL_EXSTYLE ) | WS_EX_TOOLWINDOW )

Here you can download a sample:
WIKI_DropDownColumn_NoWindowInTaskbar.zip

Double Height column headers

It wasn't obvious to me that this could be done but the business analyst really wanted it for her screen design. A coworker remembered how she had done it once: Just embed a newline in the column title and Gupta handles it automgically. Works at design time, just embed ctrl/enter in the column's "Object Title" property, or at run time using SalTblSetColumnTitle()

Call SalTblSetColumnTitle ( tblX.columnN, "Column header part 1 
		column header part 2" )

How to set popup-edit columns to read-only or to disabled state

On columns having cell-type 'Popup edit' there are only two states available:

• Editable Yes
• Editable No

When the column is editable, the text inside the popup edit box can be selected and changed.
When the column is not editable, the popup edit box is not presented when clicking on a cell.

So it is not possible to see the contents of a cell without allowing the user to change the text.

The next solution adds two more options for Popup edit columns:

• Readonly
• Disabled

The trick is to get the window handle of the popup edit box and use it to set it to read-only or disabled states.

Declare these constants

   Number: WM_USER              = 0x0400
   Number: SAM_GetExtEdit       = WM_USER + 119
   Number: EM_SETREADONLY       = 0x00CF

The constant SAM_GetExtEdit is an internal undocumented message to get the edit part of popup edit columns.

The next piece of code shows how to get the window handle of the edit box and set it to read-only or disabled.
Here is a table called tblTest which contains a column col1 having type 'Popup edit':

   Set nPopup = SalSendMsg( tblTest, SAM_GetExtEdit, SalTblQueryColumnID( tblTest.col1 ) - 1, 0 )
   If nPopup > 0
      Set hWndPopUp = SalNumberToWindowHandle( nPopup )
      ! Set it to READ ONLY
      Call SalSendMsg( hWndPopUp, EM_SETREADONLY, TRUE, 0 )
      ! Or set it to disabled
      Call SalDisableWindow( hWndPopUp )

Here you can download a sample:
WIKI_PopupEditColumn_ReadOnly.zip