CODEWITHSUNDEEP
c#filestreamreader
christian890
christian890

Reputation: 147

C# File.Read Error: File already in Use by other process

i am trying to parse through several Files, while doing so there are some values to ignore and so on. I currently did it with this Code:

double[][] rows = File  
         .ReadLines(filepath)  
         .Select(line => line
            .Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries)  
            .Where(item => !string.Equals("NAN", item, StringComparison.OrdinalIgnoreCase)))   
         .Where(items => items.Any())
         .Select(items => items
           .Select(item => double.Parse(item, CultureInfo.InvariantCulture))  
           .ToArray())
         .ToArray();

But i recently got the Error. After searching in the Internet i found out that 

 using (FileStream stream = File.Open("path to file", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
        {
            using (StreamReader reader = new StreamReader(stream))
            {
                while (!reader.EndOfStream)
                { DO SOMETHING}
            }
        }

Would fix this problem. However i can´t manage to change that Code to my needs. When i try:

      using (FileStream stream = File.Open("path to file", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
        {
            using (StreamReader reader = new StreamReader(stream))
            {
                while (!reader.EndOfStream)
                {
                    reader.ReadLine().Select(line => line
            .Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries)  
            .Where(item => !string.Equals("NAN", item, StringComparison.OrdinalIgnoreCase)))   
         .Where(items => items.Any())
         .Select(items => items
           .Select(item => double.Parse(item, CultureInfo.InvariantCulture))   
           .ToArray())
         .ToArray();
                }
            }
        }

It gives me an error on ".Split" since its not a known definition for a StreamReader... I know this maight be a really silly questions and pretty easy to solve but i can´t manage it to be done some how...

Thanks in Advance

Regards

Upvotes: 1

Views: 1707

Answers (3)

Scrobi
Scrobi

Reputation: 1215

Reader.ReadLine() will return a string. So when you do .Select on this you are projecting this into an IEnumerable<char>. You cannot then do .Split on a char.

You will need to reformat your code to work by reading one line at a time

So something line this:

reader.ReadLine()
      .Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries)
      .Where(item => !string.Equals("NAN", item, StringComparison.OrdinalIgnoreCase))
      .Where(items => items.Any())
      .Select(items => items.Select(item => double.Parse(item.ToString())).ToArray()).ToArray();

Update

To answer your comment I would most probably change the data structure from double[][] to a List<List<double>>

If you want to keep the double[][] you can do something like this.

You can change the code to add to the list while streaming the file:

List<double[]> example = new List<double[]>();

while (!reader.EndOfStream)
{
    example.Add(reader.ReadLine()
      .Split(new char[] { ';' }, StringSplitOptions.RemoveEmptyEntries)
      .Where(item => !string.Equals("NAN", item, StringComparison.OrdinalIgnoreCase))
      .Where(items => items.Any())
      .Select(item => double.Parse(item.ToString(), CultureInfo.InvariantCulture)).ToArray());
}


var returnvalue = example.ToArray();

Note

When making changes like this make sure that the results match the original code.

Upvotes: 1

Nikita V
Nikita V

Reputation: 437

Is it neccessary to use outer "using"? Try this:

    try
    {
        using (var reader = new StreamReader(filename))
        {
            while (!reader.EndOfStream)
            {
                { your split implementation }
            }
        }
    }

    // now you dont need to close a stream because
    // using statement will handle it for you

    catch // appropriate exception handling
    {

    }

Upvotes: 0

fdafadf
fdafadf

Reputation: 819

You need to replace reader.ReadLine() with reader.ReadToEnd().Split(new string[] { Environment.NewLine }, StringSplitOptions.None). Also you can write own your extension method ReadLines for the reader class.

Upvotes: 0

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