Silverlight DataGrid and Binding columns

Question

I have a silverlight datagrid control and columns autogenerate property is set to false. I am using MVVM and wants to bind the columns collection.

The data which i get is from xml. Something similar to sample code

http://blogs.msdn.com/b/deepak_verma/archive/2008/07/19/dynamic-creation-binding-of-silverlight-datagrid.aspx

Now by passing the datagrid control from xmal file to the modelview I can get the expected behavior but with that way , i am adding columns in the datagrid control.

Is there any way, so that I can bind the columns collection with the datagrid control so that no need to pass the control to view model.

-Rajesh

Answer 1

Sounds like a strange implementation of MVVM you have there. Your ViewModel should be completely independent of the View. If you want to create dynamic columns on the grid then why not expose a relevant property collection on the ViewModel, and iterate through it in a relevant method on the View code behind eg

//Used with an Infragistics XamWebGrid control
private void BuildGrid() {
    foreach (var dataItem in **ViewModel**.MyDataCollection)
    {
        var myCol = new TemplateColumn
        {
          HeaderText = dataItem.ItemNm,
          Key = dataItem.PrimaryKey
        };

        MyGrid.Columns.Add(myCol);
    }
}

You really shouldn't be passing controls from the View over to the ViewModel. The ViewModel should have no knowledge of any controls on the View.