JanetTerra
Aug 2, 2006
Stylebits and Windows Constants
Janet Terra
Recognized Windows Constants
Many of the Windows constants are recognized by Liberty BASIC by preceding that constant with an underscore . As an example, the decimal equivalent of WS_EX_TOOLWINDOW ( MSDN Defines a Tool Window here) is 128 . With the preceding underscore, Liberty BASIC accurately interprets that constant .
Print _WS_EX_TOOLWINDOW ' Prints 128
While it is most convenient to use the Windows constant itself, the numerical equivalent (either the literal or a variable) can be used just as easily in the Stylebits command.
Stylebits 0, 0, _WS_EX_TOOLWINDOW, 0is the same as
Stylebits 0, 0, 128, 0is the same as
exStyle = 128
Stylebits 0, 0, exStyle, 0
This variable must be in decimal (not hexademical) form. If necesssary, use the Liberty BASIC HexDec() function to convert a hexademical value to a decimal value.
valueHex$ = "80" ' Hexademical &80
Print HexDec(valueHex$) ' Prints 128
Caution: Although the Help File suggests Hexadecimal strings can be converted to Decimal numbers using the native HexDec() function with or without the preceding & (ampersand), it appears the use of the preceding & (ampersand) yields inconsistent results.
From the Help File
- HEXDEC( "value" )
- Description:
- This function returns a numeric decimal from a hexadecimal number expressed in a string. Hexadecimal values are represented by digits 0 - F. The hexadecimal number can be preceded by the characters "&H". The hexadecimal string must be enclosed in quote marks.
- Usage:
- print hexdec( "FF" )
- or:
- print hexdec( "&HFF")
However, try this
valueHex$ = "80" ' Hexademical &80
Print HexDec(valueHex$) ' Prints 128
valueHex$ = "&80" ' Hexademical &80
Print HexDec(valueHex$) ' Prints 0
For the purposes of this discussion, any preceding & (ampersand) will be omitted from any hexadecimal strings.
value = _WS_EX_TOOLWINDOW
Print "value = ";value ' Prints 128
valueHex$ = DecHex$(value)
Demo 1: Opening a Tool Window using the Windows Constant in the Stylebits command
' Open a Tool Window
Nomainwin
Stylebits #w, 0, 0, _WS_EX_TOOLWINDOW, 0
Open "Tool Window" for Window as #w
#w, "Trapclose QuitDemo"
Wait
Sub QuitDemo handle$
Close #handle$
End Sub
Demo 2: Opening a Tool Window using the literal decimal value in the Stylebits command
' Open a Tool Window
Nomainwin
Stylebits #w, 0, 0, 128, 0
Open "Tool Window" for Window as #w
#w, "Trapclose QuitDemo"
Wait
Sub QuitDemo handle$
Close #handle$
End Sub
Demo 3: Opening a Tool Window using a variable in the Stylebits command
' Open a Tool Window
Nomainwin
exStyle = 128
Stylebits #w, 0, 0, exStyle, 0
Open "Tool Window" for Window as #w
#w, "Trapclose QuitDemo"
Wait
Sub QuitDemo handle$
Close #handle$
End Sub
Unrecognized Windows Constants
There are well over 55,000 Windows Constants in use. Many, but not all, Windows constants are recognized by Liberty BASIC. WS_EX_LAYERED is one of the unrecognized constants. Due to the very number of entries alone, a comprehensive list of such constants would be near impossible to find. In the case of the unrecognized WS_EX_LAYERED , Google that constant to find the decimal or hexadecimal equivalent. Remember, if the constant value is given as a hexadecimal string , you must convert that hexadecimal string to the equivalent decimal number . The decimal equivalent of WS_EX_LAYERED is 524288 .
It is best to choose a meaningful variable name. In this case, we'll name the variable WS.EX.LAYERED . Liberty BASIC will halt with an error when trying to use an unrecognized Windows constant
Stylebits #w, 0, 0, _WS_EX_LAYERED, 0but will happilly accept either
Stylebits #w, 0, 0, 524288, 0or
WS.EX.LAYERED = 524288
Stylebits #w, 0, 0, WS.EX.LAYERED, 0
Combining Stylebits
Stylebits - Windows shows how to combine two or more Windows constants within the same addbits, removebits, addextendedbits or removeextendedbits of the Stylebits command. Decimal numbers and variables work just as well in combination.
Demo1: Removing the Maximize and Minimize Buttons using Windows Constants in the Stylebits command
Stylebits #w, 0, _WS_MAXIMIZEBOX or _WS_MINIMIZEBOX, 0, 0Demo2: Removing the Maximize and Minimize Buttons using literals and variables in the Stylebits command
Open "No Max/Min Boxes" for Window as #w
#w, "Trapclose QuitDemo"
Wait
Sub QuitDemo handle$
Close #handle$
End
End Sub
WS.MAXIMIZEBOX = 65536
Stylebits #w, 0, 131072 or WS.MAXIMIZEBOX, 0, 0
Open "No Max/Min Boxes" for Window as #w
#w, "Trapclose QuitDemo"
Wait
Sub QuitDemo handle$
Close #handle$
End
End Sub
Beyond Stylebits
Windows constants can be applied in many circumstances. The information here will apply to those circumstances as well.