Jul 24

Written by:
7/24/2010 8:23 AM 

I wanted to put a button that would set the current comment to “****” when the button was clicked. I am using View Model (MVVM) and normally you would need to resort to using code behind.

Actually it is simple to do.

Create a column and then Edit the Style

When the Style comes up, Edit the Template

Put a Button in the template

Click on the Button then set the DataContext…

….to the ViewModel that the main page is using.

Drop an Behavior on the Button.

You will then be able to raise any ICommand on the main ViewModel (otherwise the ICommands are “out of scope”)

However, your problem is now the button is using the “scope of the main page” you no longer have access to the row that you are currently on so you can’t pass it as a parameter.

No problem, the “contentPresenter” (the parent of the Button) is STILL bound to the “context of the current row” so you can simply pass it’s DataContext as a Parameter.

So, now the following ICommand will work:

        #region ClearCommand

        public ICommand ClearCommand { get; set; }

        public void Clear(object param)

        {

            // Clear the Comment

            RIAComment objRIAComment = (RIAComment)param;

            objRIAComment.Comment = "****";

        }

 
        private bool CanClear(object param)

        {

            // Do not allow if there is no Current RIAComment

            return (param as RIAComment != null);

        }

        #endregion

Download the code sample here:

http://silverlight.adefwebserver.com/files/RIADataGridButtonInADataGrid.zip