MVVM - how to override Binding to SaveCommand?

[Rob Ainscough]

I'm trying to figure out how to "intercept" the SaveCommand for RadRibbonBackstageItem and respond to the event in my MVVM code.

 

<telerik:RadRichTextBoxRibbonUI IsMinimized="True"  Grid.Row="0" Grid.Column="0" BackstageClippingElement="{Binding ElementName=gridRadRtbParent}" DataContext="{Binding Commands, ElementName=ManageLettersRadRTB}" CollapseThresholdSize="50,50" Title="Letter" TitleBarVisibility="Collapsed" QuickAccessToolBarPosition="BelowRibbon" ApplicationButtonContent="File">

    <telerik:RadRichTextBoxRibbonUI.Resources>
        <telerik:FontFamiliesProvider x:Key="FontFamiliesProvider" />
    </telerik:RadRichTextBoxRibbonUI.Resources>

    <!-- Menu - File -->
    <telerik:RadRichTextBoxRibbonUI.Backstage>
        <telerik:RadRibbonBackstage >
            <telerik:RadRibbonBackstageItem Header="New" Icon="/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/new.png" IsSelectable="false" telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding NewDocumentCommand}" />
            <telerik:RadRibbonBackstageItem Header="Open" Icon="/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/open.png" IsSelectable="false" telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding OpenDocumentCommand}" />
            <telerik:RadRibbonBackstageItem x:Name="FileSave"  Header="Save" Icon="/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/save.png" IsSelectable="false" telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding SaveCommand}" >

I tried to use SL5 interactivity but in order to make that work I had remove 

"DataContext="{Binding Commands, ElementName=ManageLettersRadRTB}"

from RadRichTextBoxRibbonUI which basically disables all the built in functionality ... not what I want.

 My goal is to respond with my own code when File - Save (which are RadRibbonBackstageItem) is selected from the RadRichTextBoxRibbonUI and not use the default controls Save process.

Is this possible?  If so, could you provide any hints/sample.

Cheers, Rob.

 

[Petya]

Hi Rob,

The easiest way to intercept the save command is by subscribing to the CommandExecuting/CommandExecuted events of RadRichTextBox, but this is not a very MVVM-friendly solution.

The other alternative is to create custom command(s) and set the data context of the backstage (or specific backstage item) to your view model. I'm sending you a simple example with sample implementation for the save command. It also shows how to create a DependencyProperty of type RadRichTextBox and pass it to the custom command.

In the sample I've set the data context of the backstage item to my view model, which may be a bit inconvenient if you plan on creating many custom commands, but is the only solution I could give.

<telerik:RadRibbonBackstageItem Header="Open" Icon="/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/open.png" IsSelectable="false" telerik:RadRichTextBoxRibbonUI.RichTextCommand="{Binding OpenDocumentCommand}"/>
<telerik:RadRibbonBackstageItem Header="Save" Icon="/Telerik.Windows.Controls.RichTextBoxUI;component/Images/MSOffice/16/save.png" IsSelectable="false" DataContext="{Binding ElementName=Commands}" Command="{Binding MySaveCommand}"/>

I hope this helps.

Regards,
Petya
Telerik

[Scott]

Is there an alternative to the event handlers that follows the MVVM design pattern in newer versions since this post?  Not supporting an MVVM model makes it very difficult to hack this into an MVVM application without replacing all the commands entirely.

[Tanya]

Hello Scott,

The mechanism for the commands hasn't been changed and the approach provided by Petya is still valid. You can store the commands of RadRichTextBox in the view model and change only the one that you need. While I understand that this is not the best option that could be offered, changing the way the commands work might affect many of the users of the control which is something that we strive to avoid.

Regards,
Tanya
Progress Telerik