Using the Open File Dialog Window - Page 3
       by kirupa  |  7 August 2007

In the previous page, you learned how to open a single file. In this page, let's learn how to open multiple files.

Opening Multiple Files
You can tailor your Open File dialog window to actually select multiple files if needed. The following code shows you how:

private void WindowLauncher(object sender, RoutedEventArgs e)

{

OpenFileDialog ofd = new OpenFileDialog();

ofd.Multiselect = true;

 

if (ofd.ShowDialog() == true)

{

string[] filePath = ofd.FileNames;

string[] safeFilePath = ofd.SafeFileNames;

}

}

There are only two main changes when you want to select multiple files. The first change is that you need to set your OpenFileDialog object's Multiselect property to true:

ofd.Multiselect = true;

With Multiselect set to true, you are now able to select multiple files. With multiple files, though, you cannot store the data in a single string variable like you did for the single file case earlier. This brings us to our next change where the values returned by your dialog window are stored in an array:

string[] filePath = ofd.FileNames;

string[] safeFilePath = ofd.SafeFileNames;

Notice that both filePath and safeFilePath now store an array of strings. Also, instead of using FileName and SafeFileName to store the full path and file name, you use the plural form - FileNames and SafeFileNames.

Filtering by File Extensions
Another cool Open File dialog window is learning how to filter the files you see based on the file extension. Right now, your application doesn't filter based on any extensions:

[ currently you are not filtering by extensions ]

To filter by file extensions, you use your OpenFileDialog's aptly named Filter property:

private void WindowLauncher(object sender, RoutedEventArgs e)

{

OpenFileDialog ofd = new OpenFileDialog();

ofd.Multiselect = true;

 

ofd.Filter = "Data Sources (*.txt, *.xml)|*.txt*;*.xml|All Files|*.*";

 

if (ofd.ShowDialog() == true)

{

string[] filePath = ofd.FileNames;

string[] safeFilePath = ofd.SafeFileNames;

}

}

When you run your application this time, notice that you can now filter based on Data Sources and All Files:

[ you now filter by Files of type ]

To specify your own filters, you need to provide the filter's description and the extension. The syntax you use to you specify the filter is a little weird, so let's look at the approach I used to specify my Data Sources and All Files filters:

ofd.Filter = "Data Sources (*.txt, *.xml)|*.txt*;*.xml|All Files|*.*";

The basic format is Description 1|*.ext1;*.ext2|Description 2|*.ext1;*.ext2" You separate the description and the extension(s) using the | character. If you are using multiple extensions, you separate each of them using a semicolon, and note that each extension must be preceded by the * wildcard character.

In the next page, let's look at some issues associated with our approach when using Windows Vista.

Onwards to the next page!

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