Check checkbox of selected rows within DataGrid - silverlight-5.0

Question

I have one datagrid, within which first column contains checkbox. What I want to implement is, when I check first row checkbox and then i check fifth row checkbox keeping shift button pressed then application should check all the checkbox of the selected rows (i.e. row first to fifth).
I am using MVVM pattern. I have checkall checkbox at the top of the checkbox column and command is binded to it. CheckAll checkbox working properly. Click on individual checkbox also executes command from the viewmodel which checks-unchecks selected checkbox. ViewModel's property is binded to checkbox.
What I want to do now is very similar what we see in mails (i.e. yahoo,gmail). Checkbox should check-uncheck base on row selection from keyboard using shift-key. Please inform me if I am missing out any required information for describing my issue.

Answer 1

Yup possible.
In your Datagrid that you used there is a property called SELECETIONMODE.
Set this to SelectionMode = EXTENDED,
Next->
Use this kind of code to check all the Checkboxes to true.
It is best to create a class of the data your loading. Makes it clean and easy.
If your using RIA services to load data and bind it to your datagrid your already sorted..:)
Instead of using column numbers i would recommend this highly.
private void refreshDatagrid()
{
ObservableCollection<Cars> c = --Load all your cars----;
this.mydatagrid.ItemsSource = c;
}
---To Check all the boxes
private void checkAllBoxes_Click(object sender, RoutedEventArgs e)
{
if (this.mydatagrid.SelectedItems != null)
{
foreach (Cars c in this.mydatagrid.SelectedItems)
{
if (c.isSelected != true)
{
ula.Approved = true;
}
}
}
}
--Example Object Class
class Cars {
public Cars(){}
public Nullable<bool> isSelected {get;set;}
public string carName {get;set;}
public string LicenseNumber {get;set;}
public string year {get;set;}
public string model {get;set;}
}
Of course finally Create a button in the frontend with Click="checkAllBoxes_Click"
Hope the concept is clear.
Cheers