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Posted 31 Jul 2007


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File Dialog Filter Builder

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31 Jul 2007CPOL
Helper class for building filter string for Windows file dialogs


The Windows file dialogs provide the Filter property to specify which kinds of files should be shown in the dialog. The syntax is pretty simple, but there is still scope to make a mistake and "create" a bug (with typo for example).

Using the Code

The FileDialogFilterBuilder class uses the FilterInfo structure for every filter item. The FilterInfo structure contains all information about one filter item. Using these two types are pretty simple and intuitive:

// Create builder
FileDialogFilterBuilder filterBuilder = new FileDialogFilterBuilder();
// add filter item for Word documents
filterBuilder.Infos.Add( new FilterInfo( "Word", "doc", "docx", "rtf" ) );
// add filter item for Excel documents
filterBuilder.Infos.Add( new FilterInfo( "Excel", "xls", "xlsx", "csv" ) );

// create filter item for images
FilterInfo infoImages = new FilterInfo( "Images" );
// these extensions will be used by dialog for filtering files
infoImages.Extensions = new string[] 
	{ "bmp", "jpg", "gif", "jpeg", "png", "wmf", "emf", "ico" };
// these extensions will be displayed to user with item
infoImages.VisibleExtensions = new string[] { "bmp", "jpg", "gif" };
// add item to builder
filterBuilder.Infos.Add( infoImages );

// add item with no-filter, with title "All file types"
filterBuilder.AddAllFileTypes( "All file types" );

using ( OpenFileDialog ofd = new OpenFileDialog() ) {
    // method "ToFilterString()" builds the filter string with correct syntax
    ofd.Filter = filterBuilder.ToFilterString();
    ofd.ShowDialog( this );

That's all.


  • 1st August, 2007: Initial post


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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Comments and Discussions

GeneralOrdering and Default Pin
Member 334239818-Aug-09 13:25
Member 334239818-Aug-09 13:25 
GeneralSystem extension description Pin
Chris Richner1-Aug-07 3:06
Chris Richner1-Aug-07 3:06 
GeneralRe: System extension description Pin
Jakub Mller1-Aug-07 3:44
Jakub Mller1-Aug-07 3:44 
It could be useful, but how resolve application name for filter item with *.wmv, *.avi, *.mpeg, when different application will be assigned for every file type?

Geniality is in simplicity.

AnswerRe: System extension description Pin
Chris Richner1-Aug-07 13:26
Chris Richner1-Aug-07 13:26 
GeneralRe: System extension description Pin
Anthony Daly27-Oct-09 10:46
Anthony Daly27-Oct-09 10:46 
Generalspelling mistake Pin
Michael Sync31-Jul-07 23:27
Michael Sync31-Jul-07 23:27 
GeneralRe: spelling mistake Pin
Jakub Mller31-Jul-07 23:45
Jakub Mller31-Jul-07 23:45 

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