public static FormattingTag GetTag(TextPointer start, int startIndex, int length, DependencyProperty formattingProperty, object value)
{
while (start.GetPointerContext(LogicalDirection.Forward) != TextPointerContext.Text)
{
start = start.GetNextContextPosition(LogicalDirection.Forward);
}
TextPointer contentStart = start.GetPositionAtOffset(startIndex);
TextPointer contentEnd = contentStart.GetPositionAtOffset(length);
FormattingTag tag = new FormattingTag(startIndex, length);
tag.StartPosition = contentStart;
tag.EndPosition = contentEnd;
tag.FormattingProperty = formattingProperty;
tag.Value = value;
return(tag);
}
public void ApplyPropertyValue(int startIndex, int length, DependencyProperty formattingProperty, object value)
{
TextRange documentRange = new TextRange(this.Document.ContentStart, this.Document.ContentEnd);
documentRange.ClearAllProperties();
string documentText = documentRange.Text;
if (startIndex < 0 || (startIndex + length) > documentText.Length)
{
return;
}
this.CaretPosition = this.Document.ContentStart;
this.formattingTags.Add(FormattingTag.GetTag(this.Document.ContentStart, startIndex, length, formattingProperty, value));
foreach (var formattingTag in formattingTags)
{
formattingTag.ApplyFormatting();
}
}
