I have the control placed in DataGrid
like this:
There is also a static method to do this (analogous to using the property in code to set a non-attached property rather than using the DP there).
Grid.SetRow(txtDescription, 1);
You may find this more readable.
Use DependencyObject.SetValue, passing in the DependencyProperty for Grid.Row and the value you want to assign:
this.txtDescription.SetValue(Grid.RowProperty, 1);