// Calculates and applies the minimum width necessary to accommodate the tabs in the
// specified tab control
private void adjustColumnMinWidth()
{
if (AssociatedObject == null || TabControl == null || Column < 0 ||
Column >= AssociatedObject.ColumnDefinitions.Count ||
TabControl.Items.Count == 0)
{
return;
}
ColumnDefinition cDef = AssociatedObject.ColumnDefinitions[Column];
// Difference between column width and tab control width. This difference needs to be
// preserved when calculating the new column width.
double tabControlMargin = cDef.ActualWidth - TabControl.ActualWidth;
double aggregateTabWidths = 0;
double tabPanelMargin = 0;
// Calculate width for each tab
for (int i = 0; i < TabControl.Items.Count; i++)
{
TabItem tab = TabControl.Items[i] as TabItem;
if (tab == null)
{
return; // Unexpected object type - bail out
}
double threshholdWidth = double.IsNaN(tab.MinWidth) ? 0 : tab.MinWidth;
if (tab.ActualWidth > threshholdWidth)
{
// Aggregate tab width and margin
aggregateTabWidths += tab.ActualWidth + tab.Margin.Left + tab.Margin.Right;
if (i == 0)
{
// Get the margin of the panel containing the tabs. Note that this is the only
// dimension on an element external to the tabs that is taken into account, so
// if the TabControl's template has been modified to include other elements, this
// measurement will not be sufficient.
TabPanel tabPanel = tab.FindAncestorOfType <TabPanel>();
if (tabPanel != null)
{
tabPanelMargin += tabPanel.Margin.Left + tabPanel.Margin.Right;
}
}
}
else
{
return; // nothing to measure - bail out
}
}
// Apply calculated widths as column min width. The constant 2 is applied as this is necessary
// to prevent wrapping, but walking the visual tree and measuring could not account for these
// 2 pixels
cDef.MinWidth = tabControlMargin + tabPanelMargin + aggregateTabWidths + 2;
}