Tools Windows Vol. 3 Preview – Navigation View

Customizing maximum items to be displayed in NavigationView DropDown

A breadcrumb, or breadcrumb trail, is a navigation technique utilized in user interfaces. It enables end- users to keep track of their location within programs or documents. Breadcrumbs provide a trail to get back to the starting/entry point of a folder. Essential Tools provides the NavigationView control that uses the breadcrumbs technique to keep track of locations and folders.

NavigationView now supports setting a maximum number of items to be displayed, and has the ability to prevent a pop-up window when a drop-down is clicked, which will allow you to play with the NavigationView.

The maximum number of items to be displayed in the navigation drop-down can now be controlled by registering the new BarPopUp event of NavigationView; EventArgs holds information about the current bar that is being clicked and information about the number of items to be displayed, which has a default value of 21, as with the Vista-style breadcrumb.

BarPopUp

BarPopUp is a cancellable event; hence, the pop-up window of a drop-down can be cancelled either totally or based on the currently clicked bar, which allows users to selectively block the drop-down as well. This also allows the user to determine the maximum number of items to be displayed for each and every bar item.

Below are the EventArgs of interest:

• Cancel: Cancels the pop up if true.
• CurrentBar: Holds the information about the clicked bar.
• MaximumItemsToDisplay: Determines the number of items to be displayed for the current bar item.

API added:

BarPopUp (event)

Example Use Case:

C#

this.navigationView1.BarPopup += new EventHandler(navigationView1_BarPopup);
void navigationView1_BarPopup(object sender, Syncfusion.Windows.Forms.Tools.BarPopupEventArgs e)
     {
         if (e.CurrentBar.Text.Equals("BlockedFolder"))
                e.Cancel = true;
            if(e.CurrentBar.Text.Equals("Program Files"))
                e.MaximumItemsToDisplay = 13;
            else
                e.MaximumItemsToDisplay = 5;
}

VB

Me.navigationView1.BarPopup += New EventHandler(Of Syncfusion.Windows.Forms.Tools.BarPopupEventArgs)(AddressOf navigationView1_BarPopup)
Private Sub navigationView1_BarPopup(ByVal sender As Object, ByVal e As Syncfusion.Windows.Forms.Tools.BarPopupEventArgs)
            If e.CurrentBar.Text.Equals("BlockedFolder") Then
                e.Cancel = True
            End If
            If e.CurrentBar.Text.Equals("Program Files") Then
                e.MaximumItemsToDisplay = 13
            Else
                e.MaximumItemsToDisplay = 5
            End If
End Sub