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@Rudde
Created October 7, 2020 09:55
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Let you have a moving progressbar in a C# console app.
public class ProgressBar : IDisposable, IProgress<double>
{
private const int blockCount = 10;
private readonly TimeSpan animationInterval = TimeSpan.FromSeconds(1.0 / 8);
private const string animation = @"|/-\";
private readonly Timer timer;
private double currentProgress = 0;
private string currentText = string.Empty;
private bool disposed = false;
private int animationIndex = 0;
public ProgressBar()
{
timer = new Timer(TimerHandler);
// A progress bar is only for temporary display in a console window.
// If the console output is redirected to a file, draw nothing.
// Otherwise, we'll end up with a lot of garbage in the target file.
if (!Console.IsOutputRedirected)
{
ResetTimer();
}
}
public void Report(double value)
{
// Make sure value is in [0..1] range
value = Math.Max(0, Math.Min(1, value));
Interlocked.Exchange(ref currentProgress, value);
}
private void TimerHandler(object state)
{
lock (timer)
{
if (disposed) return;
int progressBlockCount = (int)(currentProgress * blockCount);
int percent = (int)(currentProgress * 100);
string text = string.Format("[{0}{1}] {2,3}% {3}",
new string('#', progressBlockCount), new string('-', blockCount - progressBlockCount),
percent,
animation[animationIndex++ % animation.Length]);
UpdateText(text);
ResetTimer();
}
}
private void UpdateText(string text)
{
// Get length of common portion
int commonPrefixLength = 0;
int commonLength = Math.Min(currentText.Length, text.Length);
while (commonPrefixLength < commonLength && text[commonPrefixLength] == currentText[commonPrefixLength])
{
commonPrefixLength++;
}
// Backtrack to the first differing character
StringBuilder outputBuilder = new StringBuilder();
outputBuilder.Append('\b', currentText.Length - commonPrefixLength);
// Output new suffix
outputBuilder.Append(text.Substring(commonPrefixLength));
// If the new text is shorter than the old one: delete overlapping characters
int overlapCount = currentText.Length - text.Length;
if (overlapCount > 0)
{
outputBuilder.Append(' ', overlapCount);
outputBuilder.Append('\b', overlapCount);
}
Console.Write(outputBuilder);
currentText = text;
}
private void ResetTimer()
{
timer.Change(animationInterval, TimeSpan.FromMilliseconds(-1));
}
public void Dispose()
{
lock (timer)
{
disposed = true;
UpdateText(string.Empty);
}
}
}
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