I have the following code:
private void HighlightSyntax(string syntax)
{
Regex regex = null;
switch (syntax)
{
case ".xml":
regex = new Regex(@"<\/?[^>\/]*>");
break;
}
if (regex != null)
{
Input.BeginUpdate();
// I want to save scrollbar position here and then restore it
// or maybe even disable it from being changed
int lastIndex = Input.SelectionStart;
int lastLength = Input.SelectionLength;
Input.SelectAll();
// gets matches
var matches = regex.Matches(Input.Text).Cast<Match>().ToArray();
if (matches.Length > 0) // divide into tasks and select all matches
{
Color color = Color.ForestGreen;
int wordsPerTask = 500;
int tasksAmount = (matches.Length / wordsPerTask) + 1;
int start = 0;
int end = matches.Length - 1;
Task[] tasks = new Task[tasksAmount];
for (int i = 0; i < tasksAmount; i++)
{ // dividing
start = matches.Length / tasksAmount * i;
end = matches.Length / tasksAmount * (i + 1) - 1;
var start1 = start;
var end1 = end;
tasks[i] = Task.Run(() => { SelectMatchesInArr(matches, start, end, color); } );
}
if (matches.Length - 1 - end > 0)
SelectMatchesInArr(matches, end + 1, matches.Length - 1, color);
Task.WaitAll(tasks);
}
Input.Select(lastIndex, lastLength);
Input.SelectionColor = Color.Black;
// Restore Input.ScrollBarPosition here
Input.EndUpdate();
}
}
// selects matches from start to end Indexes with Color color.
private void SelectMatchesInArr(Match[] matches, int startIndex, int endIndex, Color color)
{
for (int i = startIndex; i <= endIndex; i++)
{
int selectionStart = Input.SelectionStart;
lock (_locker)
{
Input.Select(matches[i].Index, matches[i].Length);
Input.SelectionColor = color;
Input.DeselectAll();
Input.SelectionStart = selectionStart;
Input.SelectionLength = 0;
}
}
}
It highlights syntax in richtexbox, if regex matches anything related to that syntax. It all worked until I decided to divide selecting into multiple tasks.
After dividing the selection into multiple tasks, my scrollbar position is not stable. Well, I want it to be stable, I don't want it to be changed via code. How do I prevent it from being changed if I have multiple tasks manipulating over richtextbox? What should I do in my situation? Also check comments in the code, they are written in order to help you explain what I want to do.
By the way, the BeginUpdate() and EndUpdate() methods are extension methods that have been taken from here: Hans Passant's derived from richtextbox class
