StreamWriter truncating text while writing to a text file

Question

I have a huge content in a string variable and I want to write that content to a text file using stream writer. But the stream writer is truncating the text and not writing the whole content to file. Why?

using (StreamWriter sw = new StreamWriter(completeFilePath))
{
    sw.Write(txt);
}

Answer 1

After Write, use Flush method to clear buffer.

sw.Write(Html);
sw.Flush();

Answer 2

If the size is too large,

    using (StreamWriter sw = new StreamWriter(completeFilePath))
{
    sw.Write(txt);
    //just to make sure the stream writer flushes the command
    sw.Flush();
}

If the size isn't that large, I suggest to use File.WriteAllText method

//no need to Open or Close anything
File.WriteAllText(Path, txt);