Hi Adi,
In your slave combox column, you can set the style.DisplayMember to be the name of the column in the slave table that you want to see displayed in the grid, and set style.ValueMember to be the name of the column in the slave table that has values that match the values originally displayed in the grid column.
[c#]
this.gridDataBoundGrid1.DataSource = ds.Tables["Orders"]; //Primary key table.
this.gridDataBoundGrid1.Binder.InternalColumns["EmployeeID"].StyleInfo.DataSource = ds.Tables["Employees"]; //Slave key table.
this.gridDataBoundGrid1.Binder.InternalColumns["EmployeeID"].StyleInfo.DisplayMember = "FirstName"; //display the name in a primary key table for Slave key column.
this.gridDataBoundGrid1.Binder.InternalColumns["EmployeeID"].StyleInfo.ValueMember = "EmployeeID"; //slave key column name in a primary key table.
this.gridDataBoundGrid1.Binder.InternalColumns["EmployeeID"].StyleInfo.CellType = "ComboBox"; //Make it as a comobo box cell.
Sample :
http://websamples.syncfusion.com/samples/Grid.Windows/DataBoundForiegnKey_180c4462/main.htmBest regards,
Haneef