Reading large text files with streams in C#

Question

I\'ve got the lovely task of working out how to handle large files being loaded into our application\'s script editor (it\'s like VBA for our internal product for quick macr

Answer 1

Have a look at the following code snippet. You have mentioned Most files will be 30-40 MB. This claims to read 180 MB in 1.4 seconds on an Intel Quad Core:

private int _bufferSize = 16384;

private void ReadFile(string filename)
{
    StringBuilder stringBuilder = new StringBuilder();
    FileStream fileStream = new FileStream(filename, FileMode.Open, FileAccess.Read);

    using (StreamReader streamReader = new StreamReader(fileStream))
    {
        char[] fileContents = new char[_bufferSize];
        int charsRead = streamReader.Read(fileContents, 0, _bufferSize);

        // Can't do much with 0 bytes
        if (charsRead == 0)
            throw new Exception("File is 0 bytes");

        while (charsRead > 0)
        {
            stringBuilder.Append(fileContents);
            charsRead = streamReader.Read(fileContents, 0, _bufferSize);
        }
    }
}

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