private void fontFamilyTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
string text = fontFamilyTextBox.Text;
// Update the current list item.
if (SelectFontFamilyListItem(text) == null)
{
// The text does not exactly match a family name so consider applying auto-complete behavior.
// However, only do so if the following conditions are met:
// (1) The user is typing more text rather than deleting (i.e., the new text length is
// greater than the most recent selection start index), and
// (2) The caret is at the end of the text box.
if (text.Length > _fontFamilyTextBoxSelectionStart &&
fontFamilyTextBox.SelectionStart == text.Length)
{
// Get the current list item, which should be the nearest match for the text.
FontFamilyListItem item = fontFamilyList.Items.CurrentItem as FontFamilyListItem;
if (item != null)
{
// Does the text box text match the beginning of the family name?
string familyDisplayName = item.ToString();
if (string.Compare(text, 0, familyDisplayName, 0, text.Length, true, CultureInfo.CurrentCulture) == 0)
{
// Set the text box text to the complete family name and select the part not typed in.
fontFamilyTextBox.Text = familyDisplayName;
fontFamilyTextBox.SelectionStart = text.Length;
fontFamilyTextBox.SelectionLength = familyDisplayName.Length - text.Length;
}
}
}
}
}
// Update font family list based on selection.
// Return list item if there's an exact match, or null if not.
private FontFamilyListItem SelectFontFamilyListItem(string displayName)
{
FontFamilyListItem listItem = fontFamilyList.SelectedItem as FontFamilyListItem;
if (listItem != null && string.Compare(listItem.ToString(), displayName, true, CultureInfo.CurrentCulture) == 0)
{
// Already selected
return(listItem);
}
else if (SelectListItem(fontFamilyList, displayName))
{
// Exact match found
return(fontFamilyList.SelectedItem as FontFamilyListItem);
}
else
{
// Not in the list
return(null);
}
}
// Handle changes to the SelectedFontFamily property
private void OnSelectedFontFamilyChanged(FontFamily family)
{
// If the family list is not valid do nothing for now.
// We'll be called again after the list is initialized.
if (_familyListValid)
{
// Select the family in the list; this will return null if the family is not in the list.
FontFamilyListItem item = SelectFontFamilyListItem(family);
// Set the text box to the family name, if it isn't already.
string displayName = (item != null) ? item.ToString() : FontFamilyListItem.GetDisplayName(family);
if (string.Compare(fontFamilyTextBox.Text, displayName, true, CultureInfo.CurrentCulture) != 0)
{
fontFamilyTextBox.Text = displayName;
}
// The typeface list is no longer valid; update it in the background to improve responsiveness.
InvalidateTypefaceList();
}
}
