Hi,
If you have used same DataTable for two control still you can manage two to have act independently. Check the following code here where I have used same DataTable object "dTSource" for two control,one DataGridView and another Combobox control. I sorted one column of Grid while keeping the combox value intact. I used a DataView object for the purpose.
DataTable dTSource = CreateDataTable();
DataView dView = new DataView(dTSource);
dataGridView1.DataSource = dTSource.DefaultView;
comboBox1.DataSource = dView;
comboBox1.DisplayMember = "ID";
comboBox1.ValueMember = "ID";
What I did was created a new DataView object while is having the initial un-sorted view of data and is bound to ComboBox control.
The default view of the datatable is bound to GridView object.
Hope that is helpfull to you,