限制可以使用“打开文件”对话框选择的文件

Question

I got this C# windows forms application where I load either a XML file or a CSV file for some task operations. I got a Browse button. When I click the Browse button, Open File Dialog box appears and I can navigate to a location on my drive and choose the file and then upload it using an Upload button. If I load a JPG or a ZIP file or any file whose format is anything except CSV or XML, my application crashes. Is there any way of limiting the Open File Dialog box to open only CSV or XMl files alone in C#?

Answer 1

use

openFileDialog.Filter = "CSV files (*.csv)|*.csv|XML files (*.xml)|*.xml";

this way only csv files or xml files are shown. but nevertheless users can also select other filetypes if they type in the complete name - so check the filename that was selected and correct your code accordingly.

Answer 2

You can use the Filter property to let the user choose a certain type of file.

However! This is not a guarantee. A user is still able to input '(star).(star)' in the filename box and show all files. So you should check the resulting file(s) in your code as well.

You can do this with the Path.GetExtension() method.

Answer 3

You can apply a filter in your Open file dialog which only shows .xml and csv files as mentioned above. With path.getextension http://msdn.microsoft.com/en-us/library/system.io.path.getextension.aspx You can check if the user indeed selected a file with the right extension. If a wrong extension is selected, you can prompt to select a different file.

I would strongly recommend to check the file extension before upload. Just check the extension after the user had selected the file. If the wrong files was selected, just don't continue the upload/processing...