Code Edit

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Introduction

CodeEdit is a light-weight code-editor control and is provided with basic editing functionalities, except, it's supported with syntax coloring, line numbering, auto-complete, and syntax tooltip..

Background

Some software needs to provide its user an interface to input codes/scripts to be processed, like a console window or anything else. The control must be easy to handle by the developer, and easy to use by the user. But, there is no such control that is free to use out there (in my knowledge, cmiiw).

Using the Code

CodeEdit control is developed under Ai.Control namespace, and directly inherit from System.Windows.Forms.Control class. There are several public classes, enum, events, properties, and functions that are provided within CodeEdit control to support its operation:

Classes and enum

• AutoCompleteEventArgs
• LineChangedEventArgs
• SyntaxSetting
• SyntaxSettingCollection
• SyntaxUsage
• SyntaxWord
• SyntaxWordCollection

Events

• LineAdded
• LineChanged
• LineRemoved
• ShowAutoComplete

Properties

• CaretPosition
• IgnoreCase
• LineNumbers
• Lines
• SeparatorChars
• ShowDescription
• Syntaxes
• TabLength
• UseAutoCompleteSupports

Functions

• appendLine
• ensureVisible
• insertLine
• getLine
• getSelected
• getWords
• setLine
• setLineBackColor
• showAutoCompleteWindow

Description

AutoCompleteEventArgs

The AutoCompleteEventArgs class is a class derived from System.EventArgs class that is used to provide data for ShowAutoComplete event. You can decide whether to show the auto-complete window by setting the Show property of this class. You can also provide the list of syntax that will be shown in the auto-complete window by setting the value of CustomSyntaxes property of this class. The Usage property allows you to decide the syntaxes source that will be shown in the auto-complete window.

LineChangedEventArgs

The LineChangedEventArgs class is a class derived from System.EventArgs class that is used to provide data for LineAdded, LineChanged, and LineRemoved event. The LineIndex property provides the index of the line where the line is added, changed, or removed. The OldValue property provides the previous value of the line before its changed or removed, when added, the old value is always empty string. The NewValue property provides the current value of the line after its added or changed, when removed, the new value is always empty string.

SyntaxSetting

The SyntaxSetting class is a class to provide support for syntax coloring and styling.

Events

No.	Name	Arguments
1.	FontStyleChanged	EventArgs
	Occurs when font style property has been changed.
2.	SyntaxColorChanged	EventArgs
	Occurs when syntax color property has been changed.
3.	WordsChanged	EventArgs
	Occurs when syntax words has been changed.

Properties

No.	Name	Type
1.	FontStyle	FontStyle
	Gets or sets the font style used to draw the syntax-words in the CodeEdit control.
2.	Name	string
	Gets or sets the name of the syntax.
3.	SyntaxColor	Color
	Gets or sets the color used to draw the syntax-words in the CodeEdit control.
4.	Words	SyntaxWordCollection
	Gets a collection containing all words in the syntax setting.

Functions

No.	Name	Type
1.	getWordDescription	string
	Description Returns the description of a word given in the SyntaxWord object. Parameters No. Name Type 1. word string   The word as the key to search for the description. 2. ignoreCase bool   Specifies whether case-insensitive should be used when comparing the word.

SyntaxSettingCollection

The SyntaxSettingCollection class is a class inherited from CollectionBase that represent a collection of SyntaxSetting object.

SyntaxUsage

The SyntaxUsage enum specifies the usage of the syntaxes shown in auto complete window.

Values

No.	Name	Description
1.	DefaultOnly	Only syntaxes that have been assigned to the control will be used.
2.	CustomOnly	Only syntaxes provided in AutoCompleteEventArgs object will be used.
3.	Both	Both default and custom syntax will be shown.

SyntaxWord

The SyntaxWord class is a class that is used to provide data for each syntax word and its information.

Properties

No.	Name	Type
1.	Word	string
	Gets or sets the syntax word.
2.	Description	string
	Gets or sets syntax description that will be shown in the syntax tooltip window.

SyntaxWordCollection

The SyntaxWordCollection class is a class inherited from CollectionBase that represent a collection of SyntaxWord object.

Events

No.	Name
1.	LineAdded Description: Occurs when a line has been added. Parameter:  LineChangedEventArgs
2.	LineChanged Description: Occurs when a line has been changed. Parameter: LineChangedEventArgs
3.	LineRemoved Description: Occurs when a line has been removed. Parameter: LineChangedEventArgs
4.	ShowAutoComplete Description: Occurs when auto-complete window will be shown. Parameter: AutoCompleteEventArgs

Properties

No.	Name	Type
1.	CaretPosition	point
	Gets or sets a value indicating current caret position in the editor.
2.	IgnoreCase	bool
	Indicating whether case-insensitive comparison should be used when comparing syntax words. Default value is false.
3.	LineNumbers	bool
	Gets or sets a value indicating the line numbers should be shown. Default value is false.
4.	Lines	string[]
	Gets or sets the lines of text in a code edit control.
5.	SeparatorChars	string
	Gets or sets a value containing characters used as separator between words. Default value is "~!@#$%^&*()+`-={}|[]\:;"'<>?,./ ".
6.	ShowDescription	bool
	Indicating that the description window should be shown when mouse pointer os hovering over a syntax word. Default value is true.
7.	Syntaxes	SyntaxSettingCollection
	Gets a collection of SyntaxSetting objects.
8.	TabLength	int
	Gets or sets the number of spaces to draw the tab character. Default value is 4.
9.	UseAutoCompleteSupports	bool
	Gets or sets a value indicating whether auto complete supports should be used. Default value is true.

Functions

No.	Name	Type
1.	appendLine	void
	Description: Appends a string value to the end of the line array. The string value will be split into lines using return char. Parameters: No. Name Type 1. value string   A string value to be added at the end of the line array.
2.	ensureVisible	void
	Description: Ensures that the caret is visible, when the control is focused. Parameters: No. Name Type -
3.	insertLine	void
	Description: Inserts a string value at the specified index in the array. The string value will be split into lines using return char. Parameters: No. Name Type 1. index int   The index in the array where the value will be inserted. 2. value string   A string value to be inserted in the array at the specified index.
4.	getLine	string
	Description: Gets a string value at a specified index. Parameters: No. Name Type 1. index int   A zero based index indicating the index of the line.
5.	getSelected	string[]
	Description: Returns an array of string that represents current selected lines. Parameters: No. Name Type -
6.	getWords	string[]
	Description: Gets an array of string that represent all words within a line at specified index. Parameters: No. Name Type 1. index int   The index of the line inside the array.
7.	setLine	void
	Description: Sets a line value at a specified index. Parameters : No. Name Type 1. index int   A zero based index indicating the index of the line. 2. value string   The value of the line.
8.	setLineBackColor	void
	Description: Sets the line's background-color. Parameters: No. Name Type 1. index int   A zero based index indicating the index of the line. 2. backcolor Color   The background-color of the line.
9.	showAutoCompleteWindow	string
	Description: Shows auto-complete window on current caret position, using specified syntax-setting collection, and specifies the word to be highlighted. Parameters: No. Name Type 1. ssc SyntaxSettingCollection   A SyntaxSettingCollection object to be shown in the auto-complete window. 2. selectedWord string   A word to highlight in the auto-complete window.

Example

Create a new WinForms Application project, and adds CodeEdit control into Form1, and name it as codeEdit1. Sets the syntax in the form's constructor like this:

public Form1() {
	InitializeComponent();
	Ai.Control.CodeEdit.SyntaxSetting ss = new Ai.Control.CodeEdit.SyntaxSetting();
	ss.Name = "Reserved Word";
	ss.SyntaxColor = Color.Blue;
	ss.Words.Add("public", "The public keyword is an access modifier for types and type members.
    \nPublic access is the most permissive access level.\nThere are no restrictions on accessing 
    public members.");
	ss.Words.Add("this", "The this keyword refers to the current instance of the class and 
    is also used as a modifier of the first parameter of an extension method.");
	ss.Words.Add("base", "The base keyword is used to access members of the base class from 
    within a derived class.");
	ss.Words.Add("true", "Represents the boolean value true.");
	ss.Words.Add("false", "Represents the boolean value false.");
	ss.Words.Add("int", "The int keyword denotes an integral type that stores values 
    according to the size and range shown in the following table.");
	ss.Words.Add("null", "The null keyword is a literal that represents a null reference, 
    one that does not refer to any object. null is the default value of reference-type variables.");
	codeEdit1.Syntaxes.Add(ss);
	ss = new Ai.Control.CodeEdit.SyntaxSetting();
	ss.Name = "Classes";
	ss.SyntaxColor = Color.Teal;
	ss.Words.Add("ControlStyles");
	ss.Words.Add("Color");
	ss.Words.Add("Cursors");
	ss.Words.Add("Font");
	ss.Words.Add("FontStyle");
	ss.Words.Add("StringAlignment");
	codeEdit1.Syntaxes.Add(ss);
	// Add lines to the CodeEdit control.
	codeEdit1.appendLine("public CodeEdit() : base() {");
	codeEdit1.appendLine("\tthis.SetStyle(ControlStyles.AllPaintingInWmPaint, true);");
	codeEdit1.appendLine("\tthis.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);");
	codeEdit1.appendLine("\tthis.SetStyle(ControlStyles.ResizeRedraw, true);");
	codeEdit1.appendLine("\tthis.SetStyle(ControlStyles.Selectable, true);");
	codeEdit1.appendLine("\tthis.SetStyle(ControlStyles.UseTextForAccessibility, true);");
	codeEdit1.appendLine("\tthis.Cursor = Cursors.IBeam;");
	codeEdit1.appendLine("\t_defaultSyntax.SyntaxColor = Color.Black;");
	codeEdit1.appendLine("\tbase.BackColor = Color.White;");
	codeEdit1.appendLine("\tbase.Font = new Font("Consolas", 8, FontStyle.Regular);");
	codeEdit1.appendLine("}");
	// Sets LineNumbers property to true.
	codeEdit1.LineNumbers = true;
	// Sets background color of the line number 3 to yellow.
	codeEdit1.setLineBackColor(3, Color.Yellow);
}

Further Development

There are several abilities needed for further development:

• Code folding, that allows the user to selectively hide and display – "fold" – sections of a currently-edited file as a part of routine edit operations.
• Word wrap, that breaks a long line that exceeds the width of page, into lines such that it will fit in the available width of page.
• Auto indent, that automatically adds indents to a newly created line adjusted to previous line.
• Supports any font family, not only monospaced font family.