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Wx::TextCtrl

A text control allows text to be displayed and edited. It may be single line or multi-line. The multi-line version can be created with the window style TE_RICH and TE_RICH2, in which case segments of text can have visual styles applied to them: bold, italic, underline, background and foreground colour, and font. Note that if the control may need to contain longer texts – either 32k, or 64k, depending on platform, it must be created with the TE_RICH styles.

TextCtrl uses native text editing components on all platforms, and this means there are some minor inconsistencies, particularly in the treatment of styled text. For more complex rich text editing needs, consider using StyledTextCtrl, or for hypertext display, HtmlWindow

Derived from

Control

Window

EvtHandler

Object

Window styles

TE_PROCESS_ENTER The control will generate the event EVT_COMMAND_TEXT_ENTER (otherwise pressing Enter keyis either processed internally by the control or used for navigation betweendialog controls).
TE_PROCESS_TAB The control will receive EVT_CHAR events for TAB pressed – normally, TAB is used for passing to thenext control in a dialog instead. For the control created with this style,you can still use Ctrl-Enter to pass to the next control from the keyboard.
TE_MULTILINE The text control allows multiple lines.
TE_PASSWORD The text will be echoed as asterisks.
TE_READONLY The text will not be user-editable.
TE_RICH Use rich text control under Win32, thisallows to have more than 64KB of text in the control even under Win9x. Thisstyle is ignored under other platforms.
TE_RICH2 Use rich text control version 2.0 or 3.0under Win32, this style is ignored under other platforms
TE_AUTO_URL Highlight the URLs and generate theTextUrlEvents when mouse events occur over them. This style is only supported for TE_RICH Win32 and multi-line GTK2 text controls.
TE_NOHIDESEL By default, the Windows text controldoesn’t show the selection when it doesn’t have focus – use this style to forceit to always show it. It doesn’t do anything under other platforms.
HSCROLL A horizontal scrollbar will be created andused, so that text won’t be wrapped. No effect under GTK1.
TE_LEFT The text in the control will be left-justified (default).
TE_CENTRE The text in the control will be centered (currently MSW and GTK2 only).
TE_RIGHT The text in the control will be right-justified (currently MSW and GTK2 only).
TE_DONTWRAP Same as HSCROLL style: don’t wrap at all, show horizontal scrollbar instead.
TE_CHARWRAP Wrap the lines too long to be shown entirely at any position (Univ and GTK2 only).
TE_WORDWRAP Wrap the lines too long to be shown entirely at word boundaries (Univ and GTK2 only).
TE_BESTWRAP Wrap the lines at word boundaries or at any other character if there are words longer than the window width (this is the default).
TE_CAPITALIZE On PocketPC and Smartphone, causes the first letter to be capitalized.

See also window styles overview and TextCtrl.new.

Note that alignment styles (TE_LEFT, TE_CENTRE and TE_RIGHT) can be changed dynamically after control creation on MSW and GTK. TE_READONLY, TE_PASSWORD and wrapping styles can be dynamically changed under GTK but not MSW. The other styles can be only set during control creation.

TextCtrl text format

The multiline text controls always store the text as a sequence of lines separated by \n characters, i.e. in the Unix text format even on non-Unix platforms. This allows the user code to ignore the differences between the platforms but at a price: the indices in the control such as those returned by get_insertion_point or get_selection can not be used as indices into the string returned by get_value as they’re going to be slightly off for platforms using \r\n as separator (as Windows does), for example.

Instead, if you need to obtain a substring between the two indices obtained from the control with the help of the functions mentioned above, you should use get_range. And the indices themselves can only be passed to other methods, for example set_insertion_point or set_selection.

To summarize: never use the indices returned by (multiline) TextCtrl as indices into the string it contains, but only as arguments to be passed back to the other TextCtrl methods.

TextCtrl styles

Multi-line text controls support the styles, i.e. provide a possibility to set colours and font for individual characters in it (note that under Windows TE_RICH style is required for style support). To use the styles you can either call set_default_style before inserting the text or call set_style later to change the style of the text already in the control (the first solution is much more efficient).

In either case, if the style doesn’t specify some of the attributes (for example you only want to set the text colour but without changing the font nor the text background), the values of the default style will be used for them. If there is no default style, the attributes of the text control itself are used.

So the following code correctly describes what it does: the second call to set_default_style doesn’t change the text foreground colour (which stays red) while the last one doesn’t change the background colour (which stays grey):

text.set_default_style( Wx::TextAttr.new(Wx::RED) )
text.append_text("Red text\n")
text.set_default_style( Wx::TextAttr.new(nil, Wx::LIGHT_GREY) )
text.append_text("Red on grey text\n")
text.set_default_style( Wx::TextAttr.new(Wx::BLUE) )
text.append_text("Blue on grey text\n")

Constants

The values below are the possible return codes of the hit_test method:

Wx::TE_HT_UNKNOWN = -2  # this means HitTest() is simply not implemented
Wx::TE_HT_BEFORE        # either to the left or upper
Wx::TE_HT_ON_TEXT       # directly on
Wx::TE_HT_BELOW         # below [the last line]
Wx::TE_HT_BEYOND        # after [the end of line]

Event handling

The following commands are processed by default event handlers in TextCtrl: Wx::ID_CUT, Wx::ID_COPY, Wx::ID_PASTE, Wx::ID_UNDO, Wx::ID_REDO. The associated UI update events are also processed automatically, when the control has the focus.

To process input from a text control, use these event handler methods to direct the events to a block that takes a CommandEvent argument.

evt_text(id) { | event | ... } Respond to a EVT_COMMAND_TEXT_UPDATED event,generated when the text changes. Notice that this event will be sentwhen the text controls contents changes – whether this is due to user input orcomes from the program itself (for example, if SetValue() is called); see ChangeValue() fora function which does not send this event.
evt_text_enter(id) { | event | ... } Respond to a EVT_COMMAND_TEXT_ENTER event,generated when enter is pressed in a text control (which must haveTE_PROCESS_ENTER style for this event to be generated).
evt_text_maxlen(id) { | event | ... } User tried to enter more textinto the control than the limit set by set_max_length.

The following event handler works similarly for textctrls created with the TE_AUTO_URL style, but the block will instead receive a TextUrlEvent with additional information about the URL.

evt_text_url(id) { | event | ... } A mouse event occurred over an URL in the text control (MSW and GTK2 only)

Methods

TextCtrl.new

TextCtrl.new(Window parent,  Integer id,  String value = "", 
             Point pos = DEFAULT_POSITION, 
             Size size = DEFAULT_SIZE, 
             Integer style = 0, 
             Validator validator = DEFAULT_VALIDATOR, 
             String name = TextCtrlNameStr)

Constructor, creating and showing a text control.

Parameters

Remarks

The horizontal scrollbar (HSCROLL style flag) will only be created for multi-line text controls. Without a horizontal scrollbar, text lines that don’t fit in the control’s size will be wrapped (but no newline character is inserted). Single line controls don’t have a horizontal scrollbar, the text is automatically scrolled so that the insertion point is always visible.

See also

TextCtrl#create, Validator

TextCtrl#append_text

append_text(String text)

Appends the text to the end of the text control.

After the text is appended, the insertion point will be at the end of the text control. If this behaviour is not desired, the programmer should use get_insertion_point and set_insertion_point.

Note also that this means that appending text will normally auto-scroll a multiline TextCtrl to the end. However, the exact scrolling behaviour may vary by platform and by the presence of styles such as Wx::TE_WORDWRAP and Wx::TE_RICH, as different native controls are being used underneath. Scrolling behaviour can be controlled more precisely by using methods such as get_last_position, show_position, and scroll_lines after calling append_text. For displaying a log of, for example, events, ListCtrl may also be a more suitable alternative.

Parameters

See also

TextCtrl#write_text

TextCtrl#can_copy

Boolean can_copy()

Returns true if the selection can be copied to the clipboard.

TextCtrl#can_cut

Boolean can_cut()

Returns true if the selection can be cut to the clipboard.

TextCtrl#can_paste

Boolean can_paste()

Returns true if the contents of the clipboard can be pasted into the text control. On some platforms (Motif, GTK) this is an approximation and returns true if the control is editable, false otherwise.

TextCtrl#can_redo

Boolean can_redo()

Returns true if there is a redo facility available and the last operation can be redone.

TextCtrl#can_undo

Boolean can_undo()

Returns true if there is an undo facility available and the last operation can be undone.

TextCtrl#clear

clear()

Clears the text in the control.

Note that this function will generate a EVT_COMMAND_TEXT_UPDATED event.

TextCtrl#copy

copy()

Copies the selected text to the clipboard under Motif and MS Windows.

TextCtrl#create

Boolean create(Window parent,  Integer id,  String value = "", 
               Point pos = DEFAULT_POSITION, 
               Size size = DEFAULT_SIZE, 
               Integer style = 0, 
               Validator validator = DEFAULT_VALIDATOR, 
               String name = TextCtrlNameStr)

Creates the text control for two-step construction. Derived classes should call or replace this function. See TextCtrl.new for further details.

TextCtrl#cut

cut()

Copies the selected text to the clipboard and removes the selection.

TextCtrl#discard_edits

discard_edits()

Resets the internal `modified’ flag as if the current edits had been saved.

TextCtrl#emulate_key_press

Boolean emulate_key_press(KeyEvent event)

This functions inserts into the control the character which would have been inserted if the given key event had occurred in the text control. The event object should be the same as the one passed to EVT_KEY_DOWN handler previously by Widgets.

Please note that this function doesn’t currently work correctly for all keys under any platform but MSW.

Return value

true if the event resulted in a change to the control, false otherwise.

TextCtrl#get_default_style

TextAttr get_default_style()

Returns the style currently used for the new text.

See also

set_default_style

TextCtrl#get_insertion_point

Integer get_insertion_point()

Returns the insertion point. This is defined as the zero based index of the character position to the right of the insertion point. For example, if the insertion point is at the end of the text control, it is equal to both get_value()() and get_last_position()().

The following code snippet returns the character at the insertion point or an empty string if the point is at the end of the control.

if textctrl.get_last_position == textctrl.get_insertion_point
    return ''
else
   return textctrl.get_value[ textctrl.get_insertion_point, 1]
end

TextCtrl#get_last_position

TextPos get_last_position()

Returns the zero based index of the last position in the text control, which is equal to the number of characters in the control.

TextCtrl#get_line_length

Integer get_line_length(Integer line_num)

Gets the length of the specified line, not including any trailing newline character(s).

Parameters

Return value

The length of the line, or -1 if line_num was invalid.

TextCtrl#get_line_text

String get_line_text(Integer line_num)

Returns the contents of a given line in the text control, not including any trailing newline character(s).

Parameters

Return value

The contents of the line.

TextCtrl#get_number_of_lines

Integer get_number_of_lines()

Returns the number of lines in the text control buffer.

Remarks

Note that even empty text controls have one line (where the insertion point is), so GetNumberOfLines() never returns $0$.

For GTK using GTK+ 1.2.x and earlier, the number of lines in a multi-line text control is calculated by actually counting newline characters in the buffer, i.e. this function returns the number of logical lines and doesn’t depend on whether any of them are wrapped. For all the other platforms, the number of physical lines in the control is returned.

Also note that you may wish to avoid using functions that work with line numbers if you are working with controls that contain large amounts of text as this function has $O(N)$ complexity for $N$ being the number of lines.

TextCtrl#get_range

String get_range(Integer from,  Integer to)

Returns the string containing the text starting in the positions from and up to to in the control. The positions must have been returned by another TextCtrl method.

Please note that the positions in a multiline TextCtrl do not correspond to the indices in the string returned by get_value because of the different new line representations (CR or CR LF) and so this method should be used to obtain the correct results instead of extracting parts of the entire value. It may also be more efficient, especially if the control contains a lot of data.

TextCtrl#get_selection

[ Integer from, Integer to ] = get_selection()

Gets the current selection span and returns the start (from) and end (to) points as a two-element array. These two values are integer offsets within the TextCtrl’s text. If the returned values are equal, there was no selection.

Note that on some platforms, if the selection was made by click-dragging from right to left, from may be larger than to. In other words, you should not assume that from is earlier in the sequence of characters in the TextCtrl. Using ruby’s sort method should correct this.

Please note that the indices returned may be used with the other Textctrl methods but don’t necessarily represent the correct indices into the string returned by get_value() for all multiline controls under Windows (at least,)

This problem appears to be avoided if the TextCtrl is created with the Wx::TE_RICH2 style, or you can use get_string_selection to get a string containing the selected text.

TextCtrl#get_string_selection

String get_string_selection()

Gets the text currently selected in the control. If there is no selection, the returned string is empty.

TextCtrl#get_style

Boolean get_style(Integer position,  TextAttr style)

Returns the style at this position in the text control. Not all platforms support this function.

Return value

true on success, false if an error occurred – it may also mean that the styles are not supported under this platform.

See also

TextCtrl#set_style, TextAttr

TextCtrl#get_value

String get_value()

Gets the contents of the control. Notice that for a multiline text control, the lines will be separated by (Unix-style) $$n characters, even under Windows where they are separated by a $$r$$n sequence in the native control.

TextCtrl#hit_test

[ Integer result, Integer col, Integer row ] = hit_test(Point pt)

This function finds the character at the specified position expressed in pixels. If the return code is not TE_HT_UNKNOWN the row and column of the character closest to this position are returned in the col and row arguments.

Please note that this function is currently only implemented in Univ, MSW and GTK2 ports. It functionality can be faked on OS X.

See also

position_to_xy, XYToPosition

TextCtrl#is_editable

Boolean is_editable()

Returns true if the controls contents may be edited by user (note that it always can be changed by the program), i.e. if the control hasn’t been put in read-only mode by a previous call to set_editable.

TextCtrl#is_empty

Boolean is_empty()

Returns if the control is currently empty. This is the same as GetValue().empty() but can be much more efficient for the multiline controls containing big amounts of text.

2.7.1

TextCtrl#is_modified

Boolean is_modified()

Returns true if the text has been modified by user. Note that calling set_value doesn’t make the control modified.

See also

mark_dirty

TextCtrl#is_multi_line

Boolean is_multi_line()

Returns true if this is a multi line edit control and false otherwise.

See also

is_single_line

TextCtrl#is_single_line

Boolean is_single_line()

Returns true if this is a single line edit control and false otherwise.

See also

is_multi_line

TextCtrl#load_file

Boolean load_file(String filename,  Integer fileType = TEXT_TYPE_ANY)

Loads and displays the named file, if it exists.

Parameters

Return value

true if successful, false otherwise.

TextCtrl#mark_dirty

mark_dirty()

Mark text as modified (dirty).

See also

is_modified

TextCtrl#on_drop_files

on_drop_files(DropFilesEvent event)

This event handler function implements default drag and drop behaviour, which is to load the first dropped file into the control.

Parameters

Remarks

This is not implemented on non-Windows platforms.

See also

DropFilesEvent

TextCtrl#paste

paste()

Pastes text from the clipboard to the text item.

TextCtrl#position_to_xy

[ Integer x*, Integer *y ] = position_to_xy(pos)

Converts given position to a zero-based column, line number pair. If the position requested is less than 0 or greater than the length of the TextCtrl, the single value nil will be returned.

Parameters

See also

TextCtrl#xy_to_position

TextCtrl#redo

redo()

If there is a redo facility and the last operation can be redone, redoes the last operation. Does nothing if there is no redo facility.

TextCtrl#remove

remove(Integer from,  Integer to)

Removes the text starting at the first given position up to (but not including) the character at the last position.

Parameters

TextCtrl#replace

replace(Integer from,  Integer to,  String value)

Replaces the text starting at the first position up to (but not including) the character at the last position with the given text.

Parameters

TextCtrl#save_file

Boolean save_file(String filename,  Integer fileType = TEXT_TYPE_ANY)

Saves the contents of the control in a text file.

Parameters

Return value

true if the operation was successful, false otherwise.

TextCtrl#set_default_style

Boolean set_default_style(TextAttr style)

Changes the default style to use for the new text which is going to be added to the control using write_text or append_text.

If either of the font, foreground, or background colour is not set in style, the values of the previous default style are used for them. If the previous default style didn’t set them neither, the global font or colours of the text control itself are used as fall back.

However if the style parameter is the default TextAttr, then the default style is just reset (instead of being combined with the new style which wouldn’t change it at all).

Parameters

Return value

true on success, false if an error occurred – may also mean that the styles are not supported under this platform.

See also

get_default_style

TextCtrl#set_editable

set_editable(Boolean editable)

Makes the text item editable or read-only, overriding the TE_READONLY flag.

Parameters

See also

is_editable

TextCtrl#set_insertion_point

set_insertion_point(Integer pos)

Sets the insertion point at the given position.

Parameters

TextCtrl#set_insertion_point_end

set_insertion_point_end()

Sets the insertion point at the end of the text control.

TextCtrl#set_max_length

set_max_length(Integer length)

This function sets the maximum number of characters the user can enter into the control. In other words, it limits the text value length to length.

If length is 0, the previously set max length limit, if any, is discarded and the user may enter as much text as the underlying native text control widget supports (typically at least 32Kb).

If the user tries to enter more characters into the text control when it already is filled up to the maximal length, a EVT_COMMAND_TEXT_MAXLEN event is sent to notify the program about it (giving it the possibility to show an explanatory message, for example) and the extra input is discarded.

Note that under GTK+, this function may only be used with single line text controls.

Compatibility

Only implemented in MSW/GTK starting with Widgets 2.3.2.

TextCtrl#set_modified

set_modified(Boolean modified)

Marks the control as being modified by the user or not.

See also

mark_dirty, discard_edits

TextCtrl#set_selection

set_selection(Integer from,  Integer to)

Selects the text starting at the first position up to (but not including) the character at the last position. If both parameters are equal to -1 all text in the control is selected.

Note that on Windows, by default, if the TextCtrl does not have focus the selection is not shown as highlighted. Therefore the results of calling this method may not be immediately visible. If you wish the selection always to be shown, create the TextCtrl with the style Wx::TE_NOHIDESEL.

Parameters

TextCtrl#set_style

Boolean set_style(Integer start,  Integer end, 
                  TextAttr style)

Changes the style of the given range. If any attribute within style is not set, the corresponding attribute from get_default_style() is used.

Parameters

Return value

true on success, false if an error occurred – it may also mean that the styles are not supported under this platform.

See also

TextCtrl#get_style, TextAttr

TextCtrl#set_value

set_value(String value)

Sets the text value and marks the control as not-modified (which means that is_modified would return false immediately after the call to set_value).

Note that this function will generate a EVT_COMMAND_TEXT_UPDATED event.

This function is deprecated and should not be used in new code. Please use the change_value function instead.

Parameters

TextCtrl#change_value

change_value(String value)

Sets the text value and marks the control as not-modified (which means that is_modified would return false immediately after the call to SetValue).

Note that this function will not generate the EVT_COMMAND_TEXT_UPDATED event. This is the only difference with set_value. See this topic for more information.

2.7.1

Parameters

TextCtrl#show_position

show_position(Integer pos)

Makes the line containing the given position visible.

Parameters

TextCtrl#undo

undo()

If there is an undo facility and the last operation can be undone, undoes the last operation. Does nothing if there is no undo facility.

TextCtrl#write_text

write_text(String text)

Writes the text into the text control at the current insertion position.

Parameters

Remarks

Newlines in the text string are the only control characters allowed, and they will cause appropriate line breaks. See TextCtrl:: and TextCtrl#append_text for more convenient ways of writing to the window.

After the write operation, the insertion point will be at the end of the inserted text, so subsequent write operations will be appended. To append text after the user may have interacted with the control, call TextCtrl#set_insertion_point_end before writing.

TextCtrl#xy_to_position

Integer xy_to_position(Integer x,  Integer y)

Converts the given zero based column and line number to a position.

Parameters

Return value

The position value, or -1 if x or y was invalid.

TextCtrl#<<

TextCtrl << String str
TextCtrl << Integer int
TextCtrl << Float float

Operator for appending to a text control, for example:

textctrl = Wx::TextCtrl.new(parent, -1, '')
textctrl << "Welcome to text control number " << 1 << ".\n"

[This page automatically generated from the Textile source at Wed Sep 09 02:21:27 +0100 2009]