Increase columns width in Silverlight DataGrid to fill whole DG width

Question

I have a DataGrid Control which is bound to a SQL Table.

The XAML Code is:

Answer 1

Building on Henrik P's answer, this solution simply straightens out the bug with Width='*' so that you can set any column to be proportional like you can on a grid:

    private void DgSQLDataSizeChanged(object sender, SizeChangedEventArgs e)
    {
        var myDataGrid = (DataGrid)sender;

        // Do not change column size if Visibility State Changed
        if (myDataGrid.RenderSize.Width == 0) return;

        double totalActualWidthOfNonStarColumns = myDataGrid.Columns.Sum(
            c => c.Width.IsStar ? 0 : c.ActualWidth);

        double totalDesiredWidthOfStarColumns = 
            myDataGrid.Columns.Sum(c => c.Width.IsStar ? c.Width.Value : 0);

        if ( totalDesiredWidthOfStarColumns == 0 ) 
            return;  // No star columns

        // Space available to fill ( -18 Standard vScrollbar)
        double spaceAvailable = (myDataGrid.RenderSize.Width - 18) - totalActualWidthOfNonStarColumns;

        double inIncrementsOf = spaceAvailable/totalDesiredWidthOfStarColumns;

        foreach (var column in myDataGrid.Columns)
        {
            if ( !column.Width.IsStar ) continue;

            var width = inIncrementsOf * column.Width.Value;
            column.Width = new DataGridLength(width, DataGridLengthUnitType.Star);
        }
    }

I liked Henrik's answer but needed two columns to fill the extra space, like a grid.