Designing DataWindow objects for the Web DataWindow

The Web DataWindow supports most DataWindow functionality. This section describes what features to use to take full advantage of the Web DataWindow, and what features to avoid.

Using existing DataWindow objects

Many existing DataWindow objects work in the Web DataWindow. If a DataWindow object uses features that the Web DataWindow does not support, then the features are ignored. You can still use the DataWindow object if the remaining functionality is acceptable for your application. Table 10-1 lists supported and unsupported features.

**Table 10-1: Web DataWindow supported and unsupported features**
DataWindow feature	Supported and unsupported features
Presentation styles	All presentation styles except TreeView are supported. Unsupported presentation styles retrieve data but display nothing. The Grid presentation style is rendered as an HTML table if you use the HTML RenderFormat, and as a result absolute positioning is not supported and the display characteristics differ from those of XML and XHTML Web DataWindows.
Graphs	Graphs can be displayed in a DataWindow in a standalone image file or in an image stream embedded into the Web page. Graph controls inserted into DataWindow objects that use the Grid presentation style do not display. See “Rendering graphs”.
Nested and composite reports	Supported for the XHTML rendering format only.
Supported controls	Supported controls: Column, Computed Field, Graph, Text, Picture, Button, GroupBox, Rectangle. These controls are ignored: OLE Object, OLE Database Blob, RoundRectangle, Oval, InkPicture. For information on: Expressions for computed fields, see “Using expressions”. Images for Picture controls, see “Using Picture controls”. Button controls and supported actions, see “Using Button controls”.
Report controls	Report controls are supported in XHTML Web DataWindows only.
GroupBox controls	GroupBoxes cannot be rendered in Crosstab and Grid style DataWindows. The following GroupBox properties are not supported: moveable, pointer, resizeable, slideleft, slideup, font.charset, font.width.
Line controls	Only horizontal Line controls are supported. The line’s color property is always rendered, and the width property is rendered if the line is solid. Other line styles are displayed as solid lines with the default width. Vertical and slanted lines are ignored.
Rectangle controls	Rectangles cannot be rendered in a Label DataWindow with any rendering format when the layer of the Rectangle is foreground, unless the height of the DataWindow control is set to a fixed value. The following Rectangle properties are not supported: moveable, pointer, resizeable, slideleft, slideup, brush.hatch, pen.style
Retrieving data	Filtering and sorting are supported by setting properties or calling methods on the server control. Sorting can also be specified by using a client control method. See Chapter 12, “Writing Scripts for the Web DataWindow Client Control.” User-specified queries using the QueryMode property are not supported.
Updating data	Same as the DataWindowControl. The DataWindow object must contain editable columns.
Edit styles	All edit styles are supported except InkEdit and EditMask, with the exception of the DDCalendar EditMask. If the DataWindow uses the EditMask edit style, the styles specified are treated as though they were specified as a display format.
DDCalendar EditMask property	The DDCalendar EditMask property option allows for separate selections of the calendar month, year, and date. This option can be set in a check box on the Edit tab of the DataWindow painter Properties view when a Date or DateTime column with the EditMask edit style is selected. It can also be set in code, as in this example for the birth_date column: dwEmp.Modify("birth_date.EditMask.DDCalendar='Yes'") For more information, see “Using a drop-down calendar”.
DropDownDataWindows	A drop-down DataWindow must be in the same PBL as the DataWindow in which it is used. Data for drop-down DataWindows is retrieved on the server. See “Using a drop-down DataWindow”. The dddw.lines property is not supported in Web pages because the browser controls how the DropDownDataWindow displays.
Display formats	Supported, including the use of color.
Validation rules	The expression might be evaluated on the client or the server, depending on the expression. For information, see “Using expressions”.
Property expressions	Evaluated on the server.
Layout	Properties that specify autosizing of height and width or allow the user to resize or move controls, such as SlideLeft and SlideRight, are ignored.
Properties	The following properties are not supported: EditMask.Spin DataWindow object property Sparse (Suppress Repeating Values) DataWindow object property RightToLeft DataWindow control property The Limit property is not supported in multiline edit columns in a Web DataWindow. In JavaScript, the multiline edit column maps to a textarea object, and the limit property maps to a maxlength attribute, which the textarea object does not support.
Tab order	Supported in HTML 4 and later browsers.