Use the FormatColumn event to display a string different than the CellCaption property. The FormatColumn event is fired only if the FireFormatColumn property of the Column is True. The FormatColumn event lets the user to provide the cell's caption before it is displayed on the control's list. For instance, the FormatColumn event is useful when the column cells contains prices( numbers ), and you want to display that column formatted as currency, like $50 instead 50. Also, you can use the FormatColumn event to display item's index in the column, or to display the result of some operations based on the cells in the item ( totals, currency conversion and so on ).

The following VB samples use the FormatCurrency function, to display a number as a currency. The FormatCurrency VB function returns an expression formatted as a currency value using the currency symbol defined in the system control panel.

ComboBox1.Columns("Freight").FireFormatColumn = True
ComboBox1.Columns("Freight").HeaderBold = True
ComboBox1.Columns("Freight").Alignment = RightAlignment

Private Sub ComboBox1_FormatColumn(ByVal Item As EXCOMBOBOXLibCtl.HITEM, ByVal ColIndex As Long, Value As Variant)

     Value = FormatCurrency(Value, 2) ' The FormatCurrency is a VB function

End Sub

if the sample looks like following:

ComboBox1.Columns("Freight").FireFormatColumn = False
ComboBox1.Columns("Freight").HeaderBold = True
ComboBox1.Columns("Freight").Alignment = RightAlignment

For instance, you can use the FormatColumn event to display "Yes" or "No" caption for a boolean column. The following VB sample shows how to do it:

Private Sub ComboBox1_FormatColumn(ByVal Item As EXCOMBOBOXLibCtl.HITEM, ByVal ColIndex As Long, Value As Variant)
    Value = IIf(Value < 50, "Yes", "No")
End Sub

The following VB sample displays the result of adding ( concatenating ) of two cells:

Private Sub ComboBox1_FormatColumn(ByVal Item As EXCOMBOBOXLibCtl.HITEM, ByVal ColIndex As Long, Value As Variant)
    With ComboBox1.Items
        Value = .CellCaption(Item, 0) + .CellCaption(Item, 1)
    End With
End Sub

The following C++ sample displays a date column using a format like "Saturday, January 31, 2004":

void OnFormatColumnComboBox1(long Item, long ColIndex, VARIANT FAR* Value) 
{
	COleDateTime date( *Value );
	COleVariant vtNewValue( date.Format( _T("%A, %B %d, %Y") ) );
	VariantCopy( Value, vtNewValue );
}

The following VB.NET sample displays a date column using LongDate format:

Private Sub AxComboBox1_FormatColumn(ByVal sender As Object, ByVal e As AxEXCOMBOBOXLib._IComboBoxEvents_FormatColumnEvent) Handles AxComboBox1.FormatColumn
    e.value = DateTime.Parse(e.value).ToLongDateString()
End Sub

The following C# sample displays a date column using LongDate format:

private void axComboBox1_FormatColumn(object sender, AxEXCOMBOBOXLib._IComboBoxEvents_FormatColumnEvent e)
{
	e.value = DateTime.Parse(e.value.ToString()).ToLongDateString();
}

The following VFP sample displays the item's index using the FormatColumn event:

*** ActiveX Control Event ***
LPARAMETERS item, colindex, value

with thisform.ComboBox1.Items
	.DefaultItem = item
	value = .ItemToIndex(0)
endwith

before running the sample please make sure that the :

application.AutoYield = .f.

is called during the Form.Init event.

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