Question

I am writing a UI application which accept an input from the user –

up to 50,000 entries which he pastes to a Textbox, which I need to convert to List<Uint32> (Distinct)

In the process, I display the Distict list (the output) in the ‘Textbox’.

I am splitting the text and converting it to a Distinct list of Uint32
Then I convert the list to array.

private List<UInt32> ConvertTextToList(string TextBoxText)
{
string[] TextBoxSplitted = TextBoxText.Split(new string[] { Environment.NewLine},StringSplitOptions.RemoveEmptyEntries); //Fast
            var TextBoxSplittedAsList = TextBoxSplitted.ToList<string>(); //Fast
            List<UInt32> lp = TextBoxSplittedAsList.ConvertAll(new Converter<string, UInt32>(element => Convert.ToUInt32(element))); //Fast
            List<UInt32> uintList = lp.Distinct<UInt32>().ToList<UInt32>(); //Fast
            UInt32[] uintListArray = uintList.ToArray(); //Fast

            //Slow part (measured 15 sec on core2duo 2.53GHz)
            StringBuilder builder = new StringBuilder();
            Array.ForEach(uintListArray, x => builder.Append(x));                
            //Done slow part

            SomeTextBox.text = builder.ToString();

            return uintList;
}

First I tried with – ListOfHeliostatsText.Text = string.Join(",", uintListArray);

Which was slower (about 25% slower than using StringBuilder)

I feel my function designed wrong, two many conversions.

Is there anyway to improve the performance of this function ?

EDIT:
My bad,
The slow part is the ListOfHeliostatsText.Text = builder.ToString();

I will continue reading the answers.

Answer 1

You have measured incorrectly. The slow part is not:

StringBuilder builder = new StringBuilder();
Array.ForEach(uintListArray, x => builder.Append(x)); 

The slow part is:

SomeTextBox.Text = builder.ToString();

The problem is that you are feeding one huge line to the text box. If you put each string in its own line….

Array.ForEach(uintListArray, x => builder.AppendLine(x.ToString()));

…you’ll observe roughly a 50-fold speedup.