StreamWriter只写第一行

Question

I have a C# .NET 3.5 Windows Form program with this method:

    private void toLog(string sLog)
    {
        richTextBox1.Text += DateTime.Now.ToString("T") + ": " + sLog + "\n";
        richTextBox1.Update();
        richTextBox1.Refresh();
        using (StreamWriter writer = new StreamWriter("log.txt", true))
        {
            writer.WriteLine(DateTime.Now.ToString("T") + ": " + sLog);
            writer.Flush();
            writer.Dispose();
        }

    }

The idea is that I can submit log entries with it and it will write the entry to both the richtextbox and the log file.

Here's the thing... the streamwriter only writes the first time the method is called! The richtextbox updates great. Flush() and Dispose() were something I tried later out of desperation, but I guess the using block should handle that.

Any ideas? Thanks!

Answer 1

I think problem could be in StreamWriter("log.txt", : path could be changed inside your app, so you'd better to use full path here.
Example:

string dir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
string log = Path.Combine(dir, "log.txt");
using (StreamWriter writer = new StreamWriter(log, true))

Answer 2

I know I'm late to the party, but this helped me with a similar situation and maybe it'll help someone else.

I was having the same problem where the streamwriter was only writing the first line in the file and nothing else. I was able to fix it by using a FileStream:

using (FileStream fileStream = File.Open("log.txt", FileMode.Open))
{
    using (StreamWriter streamWriter= new StreamWriter(fileStream))
    { 
        writer.WriteLine(DateTime.Now.ToString("T") + ": " + sLog);
    }
}

Answer 3

You can use the example below:

using (StreamWriter writer = File.AppendText("log.txt")) 
{
    writer.WriteLine(DateTime.Now.ToString("T") + ": " + sLog);
}   

The Flush and Dispose are not necessary to use at the end of the using block, because the will be implicity called.