How to Improve File Dialogs' Performance

Environment

Product Version	Product	Author
2020.2.512	File Dialogs for WinForms	Desislava Yordanova

Description

All file dialogs are loading all directories and sub-directories of the predefined InitialDirectory and also all folders and their sub-folders that are visible on the MainNavigationTreeView on the left side. When a directory is loaded, the file dialogs are creating a DirectoryInfoWrapper object which subscribes for the Created, Changed, Renamed and Deleted events for this directory. This is the most time-consuming operation when loading the dialogs.

Solution

A possible solution is to create custom dialogs, which are not tracking the Created, Changed, Renamed and Deleted file and folder events. Thus, the performance can be improved with 30-50%.

You can also skip a directory from being loaded in the file dialogs by canceling the DirectoryRequesting event. Another hint to improve the loading time is to set the ShowNetworkLocations property to false. Its value indicates whether the dialog shows network computers in the navigation tree.

Additionally, when all directories are being traversed multiple exceptions like UnauthorizedAccessException, can occur. They are also consuming large amounts of time. You can track them by subscribing to the ExceptionRaised event of the dialog.

Improve Performance

• C#
• VB.NET

    public class MyOpenFolderDialog : RadOpenFolderDialog
    {
        protected override FileDialogFormBase CreateFileDialogForm()
        {
            return new MyOpenFolderDialogForm();
        }
    }

    public class MyOpenFolderDialogForm : RadOpenFolderDialogForm
    {
        protected override DialogResult ShowDialogCore(IWin32Window owner = null, bool addWatcher = true)
        {
            addWatcher = false;
            return base.ShowDialogCore(owner, addWatcher);
        }
    }

    public class MyOpenFileDialog : RadOpenFileDialog
    {
        protected override FileDialogFormBase CreateFileDialogForm()
        {
            return new MyOpenFileDialogForm();
        }
    }

    public class MyOpenFileDialogForm : RadOpenFileDialogForm
    {
        protected override DialogResult ShowDialogCore(IWin32Window owner = null/* TODO Change to default(_) if this is not a reference type */, bool addWatcher = true)
        {
            addWatcher = false;
            return base.ShowDialogCore(owner, addWatcher);
        }
    }

    Public Class MyOpenFolderDialog
        Inherits RadOpenFolderDialog
        Protected Overrides Function CreateFileDialogForm() As FileDialogFormBase
            Return New MyOpenFolderDialogForm()
        End Function
    End Class

    Public Class MyOpenFolderDialogForm
        Inherits RadOpenFolderDialogForm
        Protected Overrides Function ShowDialogCore(Optional ByVal owner As IWin32Window = Nothing, Optional ByVal addWatcher As Boolean = True) As DialogResult
            addWatcher = False
            Return MyBase.ShowDialogCore(owner, addWatcher)
        End Function
    End Class

    Public Class MyOpenFileDialog
        Inherits RadOpenFileDialog

        Protected Overrides Function CreateFileDialogForm() As FileDialogFormBase
            Return New MyOpenFileDialogForm()
        End Function
    End Class

    Public Class MyOpenFileDialogForm
        Inherits RadOpenFileDialogForm

        Protected Overrides Function ShowDialogCore(Optional ByVal owner As IWin32Window = Nothing, Optional ByVal addWatcher As Boolean = True) As DialogResult
            addWatcher = False
            Return MyBase.ShowDialogCore(owner, addWatcher)
        End Function
    End Class