How to Read and Write to a file at a time.

Question

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Hi all

I am trying to Read and Write the same file at a time but it is showing error like this

The process cannot access the file 'D:\sample2.txt' because it is being used by another process.

C#

using (StreamReader sr = new StreamReader(@"D:\sample1.txt"))
            {
                using (StreamReader srn = new StreamReader(@"D:\sample2.txt"))
                {
                    using (StreamWriter sw = new StreamWriter(@"D:\sample2.txt"))
                    {
                        while (!sr.EndOfStream)
                        {
                            string actualURL = sr.ReadLine();
                            while (!srn.EndOfStream)
                            {
                                string uniqueURL = srn.ReadLine();
                                if (!actualURL.Equals(uniqueURL))
                                {
                                    sw.WriteLine(uniqueURL);
                                }
                            }
                        }
                    }
                }
            }

How to solve this issue???

My Requirement:
In the Sample1 text file some repeated URLs present, i want to take out that repeated URLs.

Sample2 text file does not contain any thing

My approach:
I am checking that this string is present in the Sample2 text file or not
if not present than write in the sample2 text file else not.

But this is showing this type of error

Please help how to solve the problem and please identity if i have done any mistake

Thanks in advance

Posted 30-Jul-12 23:49pm

Mac12334

Add a Solution

5 solutions

Solution 1

You can't open a reader and a writer on the same file!
You can do it by opening a file for read-write access, becasue that can be specified as a nonexclusive lock., but trying to do exactly what you are doing will probably cause big problems: You need to output to a third file, then rename it at the end after deleting the second.

Posted 30-Jul-12 23:57pm

OriginalGriff

Comments

Mac12334 31-Jul-12 6:48am

Thanks for reply

OriginalGriff 31-Jul-12 6:59am

You're welcome

Solution 2

Check this.

http://www.c-sharpcorner.com/UploadFile/dbeniwal321/file-openwrite-method-in-C-Sharp/[^]

Posted 30-Jul-12 23:59pm

Santhosh Kumar Jayaraman

Comments

Mac12334 31-Jul-12 6:48am

Thanks For reply

Solution 3

I think we cannot read and write a page at a time. In this you reads and writes data to sample2.text at a time .This will create error.

Posted 31-Jul-12 0:00am

rejeesh k

Updated 31-Jul-12 0:01am

v2

Comments

Mac12334 31-Jul-12 6:05am

Thanks for reply

Can you please a way to solve this problem??
please

Mac12334 31-Jul-12 6:48am

Thanks for reply

Solution 4

Try this - Insted of opening for write use arraylist to add data. After complete reading done write in file.

ArrayList ar = new ArrayList();

        using (StreamReader sr = new StreamReader(@"D:\sample1.txt"))
        {
            using (StreamReader srn = new StreamReader(@"D:\sample2.txt"))
            {             
                    while (!sr.EndOfStream)
                    {
                        string actualURL = sr.ReadLine();
                        while (!srn.EndOfStream)
                        {
                            string uniqueURL = srn.ReadLine();
                            if (!actualURL.Equals(uniqueURL))
                            {
                                ar.Add(uniqueURL);
                            }
                        }
                    }
              
            }
        }
        using (StreamWriter sw = new StreamWriter(@"D:\sample2.txt"))
        {
            foreach (string temp in ar)
            {
                sw.WriteLine(temp);
            }
        }

Posted 31-Jul-12 0:10am

pradiprenushe

Comments

Mac12334 31-Jul-12 6:48am

Thanks for reply

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bhagirathimfs · Accepted Answer · 2012-07-31T00:52:00

C#

using (StreamReader sr = new StreamReader(@"D:\sample1.txt"))
            {
                while (!sr.EndOfStream)
                {
                    FileStream fileStream = new FileStream(@"D:\sample2.txt", FileMode.Open, FileAccess.ReadWrite, FileShare.Read);
                    using (StreamReader srn = new StreamReader(fileStream))
                    {
                        using (TextWriter sw = new StreamWriter(fileStream))
                        {
                            string actualURL = sr.ReadLine();

                            while (!srn.EndOfStream)
                            {
                                string uniqueURL = srn.ReadLine();
                                if (string.Compare(actualURL,uniqueURL,false) == 0)
                                {
                                    sw.WriteLine(actualURL);
                                }
                            }
                        }
                    }
                }
            }

Try the above code..

OriginalGriff is also write