Share via

LineDisplay.DisplayText Method (String)

  • Article

2/27/2008

Displays the specified string of characters.

Namespace: Microsoft.PointOfService
Assembly: Microsoft.PointOfService (in microsoft.pointofservice.dll)

Syntax

'Declaration
Public MustOverride Sub DisplayText ( _
    data As String _
)

public abstract void DisplayText (
    string data
)

public:
virtual void DisplayText (
    String^ data
) abstract

public abstract void DisplayText (
    String data
)

public abstract function DisplayText (
    data : String
)

Parameters

  • data
    The string of characters to display.

Remarks

The characters in data is processed beginning at the location that is specified by the CursorRow and CursorColumn property settings, and continue in succeeding columns.

Character processing continues to the next row when the end of a window row is reached. If the end of the window is reached with additional characters to be processed, then the window is scrolled upward by one row and the bottom row is set to blanks. If the CursorUpdate property is set to true, then CursorRow and CursorColumn are updated to point to the character following the last character of data.

Notice that scrolling does not occur when the last character of data is put at the end of a row. In this case, when CursorUpdate is true, then CursorRow is set to the row that contains the last character, and CursorColumn is set to the Columns setting (that is, to one more than the final character of the row). This stipulation guarantees that the display does not scroll when a character is written into its last position. Instead, the window does not scroll until another character is written.

The operation of DisplayText and DisplayTextAt varies for each mode:

  • Immediate mode (The MarqueeType property = None and the InterCharacterWait property = 0): Updates the window and viewport immediately.

  • Teletype mode (MarqueeType = None and InterCharacterWait not = 0): The data is queued. Queued data requests are processed in order, typically by another thread within the service object, updating the window and viewport by by using a wait time in milliseconds of the InterCharacterWait property after each character is sent to the viewport.

  • Marquee Init mode (MarqueeType = Init): Updates the window, but does not change the viewport.

  • Marquee On mode (MarqueeType not = Init): Illegal.

Special character values within data are as follows:

Value

Meaning

Carriage Return (13 Decimal)

Change the next character’s output position to the beginning of the current row.

Newline / Line Feed (10 Decimal)

Change the next character’s output position to the beginning of the next row. Scroll the window if the current row is the last row of the window.

DisplayText may cause a PosControlException to be thrown with the following ErrorCode.

Value

Meaning

Illegal

The display is in Marquee On mode, and DisplayText cannot be called when the device is in that mode.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread-safe. Any instance members are not guaranteed to be thread-safe.

See Also

Reference

LineDisplay Class
LineDisplay Members
Microsoft.PointOfService Namespace
LineDisplay.ClearText Method
DisplayTextAt
DisplayTextAt
InterCharacterWait