Version: 1.10.2.1
Build terminal emulation capabilities into your application with VT and Telnet controls.

VT ActiveX Control (Terminal Emulation)

The VT control is used to process and display data received from a host application using VT escape sequences. Use the VT control to easily display or screen-scrape received data. Features:

  • Advanced screen scraping capability.
  • Support for graphic characters.
  • Supports multinational byte encoding to display international character sets (displays Unicode characters).
  • Configurable scroll-back buffer.
  • Superior printing capabilities.
  • Built-in support for Key mapping.
  • Includes a custom VT font.
  • Includes support for VT320, VT220, VT100, VT52.
  • Numerous sample projects included.

Looking for the .NET version of this control?

 

Development Environment

The VT control can be used in many development environments including:

  • Visual Studio .NET (.NET Framework)
  • Visual Basic (VB)
  • Visual C++ (VC++)
  • FoxPro
  • PowerBuilder
  • Delphi
  • C++ Builder
  • ASP
  • Office 97/2000

Interface Members

The following are the public members of the VT control:

 

Public Properties
AnswerBack Returns or sets a string expression to be sent by the control whenever an ENQ is received.
AutoPrint Returns or sets a value that determines whether each line sent to the screen is also sent to the default system printer.
AutoRepeat Returns or sets a value that determines whether depressed keys generate more than one character.
AutoResize When the Rows, Cols, Font, ColWidth, RowHeight, or StatusLine property changes, the dimensions of the window may change to accommodate the display screen.
AutoWrap Returns or sets a value that indicates whether display text stops at the last column or wraps to the next line when a line contains more data than can fit on one row.
BackColor Returns or sets the background color of the control.
Bell Returns or sets a value that determines whether an audio bell is enabled.
BlinkingIntensity Returns or sets the "brightness" of blinking text.
BoldColor Returns or sets the color of bold text.
BufferRows Returns or sets the number of rows stored in the scrollback buffer. The default value is 72.
Cols Returns or sets the number of columns used for the display screen.
ColWidth Returns the width of a column according to the measurement units used by the container.
CursorCol Returns or sets the column position of the cursor.
CursorKeys Returns or sets a value that determines whether the cursor keys send ANSI cursor control sequences (up, down, left, right) or application control sequences.
CursorRow Returns or sets the row position of the cursor.
CursorStyle Returns or sets a value that determines whether the cursor style is a block cursor or an underline cursor.
DefaultPrinter Controls whether the system default printer or a user-selected printer is used.
DisableF1toF5 When set to True, function keys F1, F2, F3, F4 and F5 are disabled (control and shift-modified keys still work as advertised).
Enabled Returns or sets a value that determines the ability of the VT Control to retrieve external events, capture focus for the control, and display the cursor.
Font Returns or sets the font used in the display of the control. The default value is 11-point VT220_ascii font.
ForeColor Returns or sets the foreground color used for text. The default value is black.
hWnd Returns the handle to the window of the VT Control. The window handle is needed for specialized message handling or Windows API calls.
Inverted Returns or sets a value that determines whether the foreground and background colors are switched.
Keypad Returns or sets a value that determines whether the keypad sends ASCII characters or escape sequences.
NationalCharSet Returns or sets the national character set for use in VT220 7-bit or VT320 7-bit emulation modes to display special characters that normally require 8-bit emulation mode.
NewLine Returns or sets the end-of-line character sequence to either a single CR or CR/LF combination.
NormalIntensity Returns or sets the "brightness" of normal text.
PrinterController Returns or sets a value that determines if to stop the display of text and only send data to the default system printer.
PrintPassthrough Returns or sets a value that determines if printing bypasses the normal printer drivers and prints directly to the printer port.
RowHeight Returns the height of a single character (or line) according to the measurement units used by the container.
Rows Returns or sets the number of rows being used for the display screen.
ScrollType Returns or sets a value that determines whether to use jump scrolling or smooth scrolling in the display screen.
SelLength Returns or sets the length of the number of characters selected.
SelStart Returns or sets the starting index of the characters currently selected.
StatusLine Returns or sets a value that indicates whether a 25th line is displayed as a status line when in VT320 7-bit or 8-bit mode.
Tabs Returns or sets a list of comma-delimited tab positions.
TermType Returns or sets the terminal type to emulate.
Text Returns the characters contained in the scroll-back buffer and display screen.
Public Methods
About Show the About Box.
Clear Clears the scrollback buffer and all rows in the display screen.
Display Displays a text string or byte array and interprets all escape sequences.
EnsureVisible Moves the display to ensure the specified row is visible.
PrintCursorLine Sends a copy of the line the cursor is currently on to the default system printer.
PrintScreen Sends a copy of the current display screen to the default system printer.
PrintCursorLine Sends a copy of the line the cursor is currently on to the default system printer.
PrintScreen Sends a copy of the current display screen to the default system printer.
PrintSelected Prints the currently selected text.
Public Events
Click Fires when the user presses or releases a mouse button when the mouse pointer is on the VT Control window and the Enabled property is set to True. Use this event to determine the states of the mouse buttons, virtual Shift key, and virtual Control key when a mouse button is depressed or released.
KeyDown Fires when the user depresses a key, the Enabled property is set to True, and the VT Control has focus. You can set KeyCode to 0 (the KeyPress event will NOT be called) and send your own substitution string to the host (this is how you can map individual keys to any arbitrary character sequence).
KeyPress Fires when the user depresses a key, the Enabled property is set to True, and the VT Control has focus. This event indicates what data may be sent to the host. The KeyDown event can be used for any key substitutions and fires prior to the KeyPress Event.
NewLine Fires when the cursor in the VT display changes rows. This event is useful for capturing data to a disk file or other destination.
Resize Fires when the width or height of the VT Control changes. When the AutoResize property is True, this can occur when the Rows, Cols, Font, ColWidth, RowHeight or StatusLine property changes. It may be convenient to resize the size of the parent form when this event fires.
   

Code Example

How easy is the VT ActiveX component to use? Check out the following VB example below, which demonstrates displaying a text string.

Private Function CSI(s As String) As String
   CSI = Chr(27) & "[" & s 'CSI = Esc [
End Function

Private Sub Form_Load()
   On Error GoTo OnError ' use intrinsic error handling
   Vt1.TermType = vt320_7 'Set terminal type to VT320 7-bit emulation
   Vt1.Display CSI("4m") 'Underline Mode
   Vt1.Display "This text is underlined and displayed on screen"
   Exit Sub
OnError: ' Any error jumps here
   Debug.Print "Error #" + CStr(Err.Number) + ": " + Err.Description
End Sub