How to set column style properties for the nested tables in the WinForms GridGroupingControl?

Change the column styles

You need to get the TableDescriptors for the parent table, child table, and grandchild table from the WinForms GridGroupingControl and set the needed column properties like BackColor, TextColor, Width, etc. for each table through the GridColumnDescriptor.

//Use the tabledesciptor to set the properties.
//Sets some parent properties.
GridTableDescriptor parentTD = (GridTableDescriptor)engine.TableDescriptor;

//Sets backcolor to the column.
parentTD.Columns["ParentName"].Appearance.AnyCell.BackColor = Color.LightGoldenrodYellow;

//Sets width of the column.
parentTD.Columns["ParentName"].Width = 120;

//Sets some child properties.
GridTableDescriptor childTD = parentTD.Relations["ParentToChild"].ChildTableDescriptor;

//Sets backcolor to the column.
childTD.Columns["Name"].Appearance.AnyCell.BackColor = Color.LightPink;

//Sets width of the column.
childTD.Columns["Name"].Width = 160;

//Sets some grandchild properties.
GridTableDescriptor grandChildTD = childTD.Relations["ChildToGrandChild"].ChildTableDescriptor;

//Sets backcolor to the column.
grandChildTD.Columns["Name"].Appearance.AnyCell.BackColor = Color.Red;

//Sets width of the column.
grandChildTD.Columns["Name"].Width = 190;

'Use the tabledesciptor to set the properties.
'Sets some parent properties.
Dim parentTD As GridTableDescriptor = CType(engine.TableDescriptor, GridTableDescriptor)

'Sets backcolor to the column.
parentTD.Columns("ParentName").Appearance.AnyCell.BackColor = Color.LightGoldenrodYellow

'Sets width of the column.
parentTD.Columns("ParentName").Width = 120

'Sets some child properties.
Dim childTD As GridTableDescriptor = parentTD.Relations("ParentToChild").ChildTableDescriptor

'Sets backcolor to the column.
childTD.Columns("Name").Appearance.AnyCell.BackColor = Color.LightPink

'Sets width of the column.
childTD.Columns("Name").Width = 160

'Sets some grandchild properties.
Dim grandChildTD As GridTableDescriptor = childTD.Relations("ChildToGrandChild").ChildTableDescriptor

'Sets backcolor to the column.
grandChildTD.Columns("Name").Appearance.AnyCell.BackColor = Color.Red

'Sets width of the column.
grandChildTD.Columns("Name").Width = 190