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CLS Statement Details
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CLS [0 | 1 | 2]
Usage Notes
■ If no object is specified, CLS behavior is determined by its location
in code:
• If CLS is used in a form module, it is a method, and applies to the
default form. See: ◄CLS Method►
• If CLS is in a non-form or code module, it is a statement, and applies
to the entire screen.
■ If CLS is used as a statement (with the arguments 0, 1, or 2) when forms
are showing, Visual Basic generates the error message, "Invalid
when forms are showing."
■ To use the CLS statement with arguments 0, 1, or 2, you must first
unload or hide any visible forms.
See: ◄HIDE Method► ◄UNLOAD Statement►
■ The behavior of a particular CLS statement depends on:
• The CLS statement argument ( 0, 1, 2, or none).
• The current screen mode.
• Whether or not a VIEW statement has been executed that has changed the
graphics viewport from the default of the entire screen.
• Whether or not a VIEW PRINT statement has been executed that has
established a user-defined text viewport.
• Whether or not a KEY ON statement has been executed that has
established the bottom text line as a list of function-key
assignments. The bottom line on the screen may be 25, 30, 43, or 60,
depending on the current screen mode.
■ The following conditions determine how the CLS statement works with
graphics and text viewports:
• Screen mode 0 has only a text viewport. All other screen modes have
both a text and graphics viewport.
• The default graphics viewport is the entire screen.
• The default text viewport is the entire screen, except for the bottom
line of text.
• After a user-defined graphics viewport (or "clipping region") has been
established by executing a VIEW statement, it is reset to the default
by executing any of the following statements:
■ VIEW without arguments
■ CLEAR
■ Any SCREEN statement that changes the screen resolution
See: ◄CLEAR Statement► ◄SCREEN Statement► ◄VIEW Statement►
• After a user-defined text viewport has been established by executing
a VIEW PRINT statement, it is reset to the default by executing any of
the following statements:
■ VIEW PRINT without arguments
■ Any text-oriented statement (such as WIDTH) that changes the number
of text columns or text lines on the screen
See: ◄VIEW PRINT Statement► ◄WIDTH Statement►
• If the KEY ON statement has been executed, CLS statement regenerates
the bottom screen line as the function-key assignment list or as a
line of blank characters.
See: ◄KEY Statement (Assignment)►
■ The following table summarizes how the CLS statement works:
Statement Condition Operations Performed
═════════ ════════════════════ ══════════════════════════════════
CLS 0 Any screen mode or • Clears entire screen of all text
combination of user- and graphics except bottom text
defined viewports line
• Clears graphics viewport
• Regenerates bottom text line
• Returns cursor to home
CLS 1 Graphics screen mode • Clears default graphics viewport
with no user-defined • Does not clear text viewport
graphics viewport • Regenerates bottom text line
• Returns cursor to home
CLS 1 Graphics screen mode • Clears user-defined graphics
with user-defined viewport
graphics viewport • Does not clear text viewport
• Does not regenerate bottom text
line
• Does not return cursor to home
CLS 1 In screen mode 0 No effect
(text mode)
CLS 2 Any screen mode • Clears text viewport
• Does not clear graphics viewport
• Does not regenerate bottom text
line
Note: The bottom line of text will
not be cleared even if included in
the user-defined text viewport.
CLS Graphics-screen mode • Clears default graphics viewport
with no user-defined • Regenerates bottom text line
graphics viewport • Returns cursor to home
CLS Graphics-screen mode • Clears graphics viewport
with user-defined • Does not regenerate bottom text
graphics viewport line
• Does not return cursor to home
CLS In Screen mode 0 • Clears text viewport
(text mode) • Regenerates bottom text line
• Returns cursor to home