read/write a file at same time

 

Check if the below code is helpful

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FileStream fs = new FileStream(@"C:\Forums\FileReformat\tc.txt", FileMode.Open, FileAccess.ReadWrite);

StreamReader sr = new StreamReader(fs);

StreamWriter sw = new StreamWriter(fs);

sr.BaseStream.Seek(0, SeekOrigin.Begin);

Console.WriteLine(sr.ReadToEnd());

sw.WriteLine("this is test write line1");

sw.Flush();

sr.BaseStream.Seek(0, SeekOrigin.Begin);

Console.WriteLine(sr.ReadToEnd());

sw.WriteLine("this is test write line2");

sw.Flush();

sr.BaseStream.Seek(0, SeekOrigin.Begin);

Console.WriteLine(sr.ReadToEnd());

Console.Read();

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and here is the output

__________

InitialText

InitialText

this is test write line1

InitialText

this is test write line1
this is test write line2

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but i have to do that

if i open the file read and  close then  again open for write, lost too much time

in my case i am reading from a port and writing data to file

and same time i have to use that file also for something else.

 

do you know any method about this?

technically, it's not possible to do it at the exact same time because you have the file open while you are writing to it, so you can't open it to read it.  you must close the file after writing to it before you can read from it(or vice versa).