How to Create Special Effects in a Grid

• Microsoft Visual FoxPro for Windows, versions 3.0, 5.0

SUMMARY

Developers often need to dynamically control attributes of a Grid. A common example of this is a ledger, where the odd rows are presented in one color and the even rows in another color. Visual FoxPro uses the properties that have the prefix 'Dynamic' to achieve this.

MORE INFORMATION

The DynamicBackColor, DynamicForeColor, DynamicFontBold, DynamicFontItalic, DynamicFontStrikeThru, DynamicFontUnderline, DynamicFontName, and DynamicFontSize properties dynamically specify an attribute of a Column object within a grid. As their Dynamic prefix implies, these properties are reevaluated each time the Grid control is refreshed, and do not need to be reset manually.

If the properties listed above apply to all of the columns across a row, the whole row will be affected. Use the SETALL method to modify one property of all of the columns of a row. On the other hand, part of a row will have a different display if the Dynamic property only applies to a limited number of columns. The two examples that follow illustrate the use of the DynamicBackColor property applied to all of the columns and the DynamicFontUnderline property applied to one column in the grid.

Staggered List Example

This example displays even rows in red, and odd rows in blue. It uses the DynamicBackColor property and the SETALL method to modify the colors of the columns.

1. Create a form, and then add SAMPLES\DATA\CUSTOMER to the DataEnvironment (DE).

2. Drag the Customer table by its title bar from the DE to the Form. A grid should automatically be added to the form, and its RecordSource should be set to 'customer'.

3. Place the following code in the Init event-handler of the Grid or the Init of the Form.

         cexpr = "IIF(MOD(RECNO('customer'),2) = 0, RGB(255,0,0), ;
            RGB(0,255,0))"
   
         THIS.SetAll('DynamicBackColor', cExpr, 'Column')
   
      NOTE: This step only works if the records are in natural order. It
      doesn't work if the table is indexed.
   
   

Modifying a Specific Cell Example

This example illustrates how to modify the font of a specific cell using the DynamicFontUnderline property.

1. Repeat Step 1 and Step 2 from the previous example.

2. In the Property Sheet, select Grid, and set the value of ColumnCount to 3.

3. In the Property Sheet select Column1, and then place the following code in the DynamicFontUnderline property.

         IIF(cust_id="ANTON",.T.,.F.)
   

Note that the DynamicColor property takes a character value, whereas the DynamicFontUnderline property accepts a logical value.