Hide Save button, when there are Data Validations Errors in Silverlight

See more:

Silverlight5

Hi I am building a Silverlight page in MVVM pattern, where I am performing validations as below

http://msdn.microsoft.com/en-us/library/dd901590(VS.95).aspx[^]

Now I want to disable Save button when there are Validation erros on page, restricting user to click Save with wrong inputs.

Can any one help me to do this task. Thanks in advance