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Working with Files
5:53Learn how to use classes in the System.IO namespace to find and retrieve directory and file information.
We'll be using Visual Studio
2015 Community Edition to
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build a console application.
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Be sure to follow along and
pause the video, or
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slow me down if you need to catch up.
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Now, let's create a project.
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So we'll go to File>New>Project.
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And in the templates here,
I'll choose Console Application.
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Since we wanna analyze soccer
statistics in this application,
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we can name it Soccer Stats.
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I'm gonna show you some useful tools
that we'll need when working with
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files on the file system.
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We're going to need to add
the System.IO namespace,
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because we'll be working
with IO operations.
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Using system.io his namespace contains
a lot of the classes will be working with.
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First let's create a text file
in our project, right-click and
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add item, then I'll choose
general category over here, and
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Text File and we can name it data.text.
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Eventually we're going to use
this file in our application but
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will need to change
a property on it though so
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that it will be copied to the output
directory when we compile our program.
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Right-click and choose properties.
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It's down here.
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Copy to Output Directory, and
I'll change that to Copy if newer.
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This will copy our text file to the output
directory when we build or deploy but
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only if it's changed.
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Let's build, and we'll see if the file
is put into the output directory.
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I'm going to copy this file path here.
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And we can go check out our text file.
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CTRL+C to copy.
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And I've got an Explorer
window right here.
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Paste it into the address bar and
there's our file.
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Let's explore some of the stuff
we can do with the file system.
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The directory class, directory is
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a static class in the system.IO namespace
that gives us some static methods for
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traversing directories or
folders on your system.
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It's got a bunch of static methods for
us to create files or
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list files in a directory.
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Let's see what we've got
here in IntelliSense.
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All right, we've got CreateDirectory,
see if it exists.
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EnumerateFiles that'll list files.
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Hm, this one looks useful,
GetCurrentDirectory.
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It gets the current working
directory of the application.
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Let's call that and
we'll assign it to a string.
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Called currentDirectory,
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And we need to call
the method in semi-colon.
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We'll set a break point at the end
of our main method here so
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we can see what the value
of the directory string is.
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We'll run it with F5.
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And I can hover over it to see the value.
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So, there's a couple of
things we should note here.
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There are two backslashes that
are separating each directory segment.
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In a string, the backslash is a special
character that's used in escape sequences.
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We'll get into the different string
escape sequences a little later on
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in this course.
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For now, though,
in this string each set of two backslashes
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represents a single
backslash in the file path.
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And since our app is
running in debug mode,
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executable is compiled into the bin
debug folder under our solution folder.
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Let's go ahead and stop debugging.
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There's another class called
DirectoryInfo that we can
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use when working with directories.
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We can instantiate a DirectoryInfo object,
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directory, and new DirectoryInfo, and
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we'll pass it the string
of the current directory.
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The DirectoryInfo object
now gives us methods for
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working with the directory itself or
the files it contains.
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Let's go check out the MSDN documentation
on the class by hitting F1 while
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the cursor is on DirectoryInfo.
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Well, we've got some
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typical file system properties like
creation time and last right time.
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Let's check out the methods.
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We can use the get files method to return
a file list from the current directory.
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Let's do that in our console application.
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So I'll do a Var files equals
directory dot get files.
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Then we can do a loop to iterate over
the files and print out the names for
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each var file in files.
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Open and close curly brace and
Console.WriteLine and
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we'll print out the file name.
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Let's run it with F5.
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There's our text file we created,
data.txt.
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We can also give this
method a search pattern,
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In the GetFiles method we can
use an asterisk as a wildcard.
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So, to get all the text files we can
pass a string asterisk dot text.
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Let's see what it gives us now
we only get our text file.
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