The error is probably in the
label5.Text = i.ToString();
label5.Update();
just to make a test I've written something like:
for (int i = 0; i < int.MaxValue; i++)
{
label1.Text = i.ToString();
label1.Update();
}
The app freezes around 16000-18000 (Windows 7 Pro SP1 x64, the app running both x86 and x64).
What probably happens is that by running your long operation in the main thread of the app, you stall the message queue of the window, and at a certain point it freezes. You can see that this is the problem by adding a
Application.DoEvents();
instead of the
label5.Update();
But even this is a false solution. The correct solution is moving the copying on another thread and updating the control every x milliseconds, using the Invoke method (because you are on a secondary thread),
For example:
public void Copy(string source, string dest)
{
const int updateMilliseconds = 100;
int index = 0;
int i = 0;
StreamWriter writefile = null;
try
{
using (StreamReader readfile = new StreamReader(source))
{
writefile = new StreamWriter(dest + index);
// Initial value "back in time". Forces initial update
int milliseconds = unchecked(Environment.TickCount - updateMilliseconds);
string content;
while ((content = readfile.ReadLine()) != null)
{
writefile.Write(content);
writefile.Write("\r\n"); // Splitted to remove a string concatenation
i++;
if (i % 1000000 == 0)
{
index++;
writefile.Dispose();
writefile = new StreamWriter(dest + index);
// Force update
milliseconds = unchecked(milliseconds - updateMilliseconds);
}
int milliseconds2 = Environment.TickCount;
int diff = unchecked(milliseconds2 - milliseconds);
if (diff >= updateMilliseconds)
{
milliseconds = milliseconds2;
Invoke((Action)(() => label5.Text = string.Format("File {0}, line {1}", index, i)));
}
}
}
}
finally
{
if (writefile != null)
{
writefile.Dispose();
}
}
// Last update
Invoke((Action)(() => label5.Text = string.Format("File {0}, line {1} Finished", index, i)));
}
and call it with:
var thread = new Thread(() => Copy(@"C:\Temp\lst.txt", @"C:\Temp\output"));
thread.Start();
Note how it will write the label5 every 100 milliseconds, plus once at the beginning (by setting the initial value of milliseconds "back in time"), each time the output file is changed (by setting the value of milliseconds "back in time") and after having disposed everything.
An even more correct example can be written by using the BackgroundWorker class, that exists explicitly for this scenario. It has an event, ProgressChanged, that can be subscribed to update the window.
Something like this:
private void button1_Click(object sender, EventArgs e)
{
BackgroundWorker backgroundWorker = new BackgroundWorker();
backgroundWorker.WorkerReportsProgress = true;
backgroundWorker.ProgressChanged += backgroundWorker_ProgressChanged;
backgroundWorker.RunWorkerCompleted += backgroundWorker_RunWorkerCompleted;
backgroundWorker.DoWork += backgroundWorker_DoWork;
backgroundWorker.RunWorkerAsync(new string[] { @"C:\Temp\lst.txt", @"C:\Temp\output" });
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
string[] arguments = (string[])e.Argument;
string source = arguments[0];
string dest = arguments[1];
const int updateMilliseconds = 100;
int index = 0;
int i = 0;
StreamWriter writefile = null;
try
{
using (StreamReader readfile = new StreamReader(source))
{
writefile = new StreamWriter(dest + index);
// Initial value "back in time". Forces initial update
int milliseconds = unchecked(Environment.TickCount - updateMilliseconds);
string content;
while ((content = readfile.ReadLine()) != null)
{
writefile.Write(content);
writefile.Write("\r\n"); // Splitted to remove a string concatenation
i++;
if (i % 1000000 == 0)
{
index++;
writefile.Dispose();
writefile = new StreamWriter(dest + index);
// Force update
milliseconds = unchecked(milliseconds - updateMilliseconds);
}
int milliseconds2 = Environment.TickCount;
int diff = unchecked(milliseconds2 - milliseconds);
if (diff >= updateMilliseconds)
{
milliseconds = milliseconds2;
worker.ReportProgress(0, new int[] { index, i });
}
}
}
}
finally
{
if (writefile != null)
{
writefile.Dispose();
}
}
// For the RunWorkerCompleted
e.Result = new int[] { index, i };
}
void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
int[] state = (int[])e.UserState;
label5.Text = string.Format("File {0}, line {1}", state[0], state[1]);
}
void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
int[] state = (int[])e.Result;
label5.Text = string.Format("File {0}, line {1} Finished", state[0], state[1]);
}
