Problem with C# StreamWriter

The following code reads a file (one at a time from an array) into a string, replaces a matched pattern inside the string, then appends it to the file.

I want it to overwrite, instead of append. What am I doing wrong here?

using (FileStream fs = new FileStream(fileList[i], FileMode.Open))
using (StreamReader fileIn = new StreamReader(fs, true))
{
    String file = fileIn.ReadToEnd().ToLower();
    MessageBox.Show(file);


    if (file.Contains(oPath))
    {
        updated++;
        file = file.Replace(oPath, nPath);

        using (StreamWriter replaceString = new StreamWriter(fs, Encoding.Unicode))
        {
      开发者_如何学编程          replaceString.Write(file);
                listBoxResults.Items.Add(fileList[i]);
        }
    }
}

You're writing to the file after reading from it - so the "cursor" in the FileStream is at the end.

Rather than handling the stream yourself, it would be simpler to use:

String file = File.ReadAllText(fileList[i]).ToLower();

... perform replacements etc ...

File.WriteAllText(fileList[i], file);

The second parameter of "StreamWriter" is: "append". So you should try:

StreamWriter replaceString = new StreamWriter(fs, false, Encoding.Unicode)