Navigating in a textfile with StreamReader?

[Jaga]

Hi,

how can I read the same passage in a textfile several times?

I'm writing a little textgenerator. It reads lines from a file, replaces
the variables, and writes it in an other file. Some lines I have to read
several times and write them with other values.

What is wrong with this code:
using (StreamWriter swr = new StreamWriter(outPath))
{
using (StreamReader srd = new StreamReader(inPath,
System.Text.Encoding.Default, false))
{
long offset;
string line;
while ((line = srd.ReadLine()) != null)
{
switch (line)
{
case "XY...":
//mark the position
offset = srd.BaseStream.Position;
break;
case "YZ...":
if (...)
{
//jump back to the position
srd.BaseStream.Position = offset;
srd.DiscardBufferData();
}
break;
}
...
}
}
}

thanks

Jaga

 

[Jon Skeet [C# MVP]]

how can I read the same passage in a textfile several times?

I'm writing a little textgenerator. It reads lines from a file, replaces
the variables, and writes it in an other file. Some lines I have to read
several times and write them with other values.

What is wrong with this code:

<snip>

You're using the base stream's position to calculate where to "seek"
to, which may well be inaccurate because more will have been buffered.

Unfortunately if you don't *really* know where you want to seek to, the
seeking part (setting the position and then discarding the buffered
data) won't help much.

I can't immediately think of an easy way round this problem.

 

[Ignacio Machin \( .NET/ C# MVP \)]

Hi Jaga,

If you are reading on a by line basis you could read all the lines in a
memory structure, like an ArrayList for example and then have a pointer to
the current processing line, in this way when you finish with the current
line all you have to do is increment it. , in this way you can place marks
as they will be indexes in the ArrayList .

Hope this help,

 

[Jaga]

Hi Ignacio,

I wish, I could solve the problem by StreamReader itself, but it is a really
good idea, I try it.

thanks,
Jaga


PS: A read command of the StreamReader updates not the property "Position"
of the BaseStream, but it updates an internal Field "charPos". Do anybody
knows why Microsoft dosn't make it public?