Calculating the progress percentage

Question

How I calculate the percentage of a file that is loading in loop?

For example:

ProcessStartInfo p = new ProcessStartInfo();
Process process = Process.Start(p);
StreamReader sr = process.StandardOutput;
char[] buf = new char[256];
string line = string.Empty;
int count;

while ((count = sr.Read(buf, 0, 256)) > 0)
{
    line += new String(buf, 0, count);
    progressBar.Value = ???
}

`

How I do this? Thanks in advance

Answer 1

You'd need to know the eventual amount of output to expect - otherwise you have no way of giving a proportion of the output which has already been completed.

If you know it's going to be a certain size, you can use:

// *Don't* use string concatenation in a loop
StringBuilder builder = new StringBuilder();
int count;
while ((count = sr.Read(buf, 0, 256)) > 0)
{
    builder.Append(buf, 0, count);
    progressBar.Value = (100 * builder.Length) / totalSize;
}

This assumes a progress bar with a minimum of zero and a maximum of 100 - it also assumes that the overall length is less than int.MaxValue / 100. Another approach is simply to make the progress bar maximum value the overall length, and set the progress bar value to builder.Length.

You'll still need to know the overall length before you start though, otherwise you can't possibly give progress as a proportion.