无法将类型为“System.Data.DataTable”的对象强制转换为类型“System.Data.DataSet
dbCmdBuilder   =   new   OleDbCommandBuilder(dbAdapter); 
 DataSet   ds   =   new   DataSet(); 
 ds   =   (System.Data.DataSet)DataGridView实例.DataSource; 
 dbAdapter.Update(ds);   
 提示无法将类型为“System.Data.DataTable”的对象强制转换为类型“System.Data.DataSet”     
 请问该怎样修改上面的代码?
------解决方案--------------------dbCmdBuilder = new OleDbCommandBuilder(dbAdapter); 
 DataSet ds = new DataSet(); 
 ds.Tables.Add((System.Data.DataTable)DataGridView实例.DataSource); 
 dbAdapter.Update(ds); 
------解决方案--------------------ds.Tables.Add( DataGridView实例.DataSource as DataTable ); 
 dbAdapter.Update(ds); 
------解决方案--------------------DataTable dt = DataGridView.DataSoruce as DataTable;   
 daAdapter.Update(dt.DateSet);
------解决方案--------------------哎……这么多牛人……   
 DataSet dataSet; 
 DataTable dataTable = gridView.DataSource as DataTable; 
 if ( dataTable == null ) 
 { 
   dataSet = gridView.DataSource as DataSet; 
   if ( dataSet == null ) 
     throw new NotSupportedException(); 
 }   
 if ( dataSet == null ) 
 { 
   if ( dataTable.DataSet != null ) 
     dataSet = dataTable.DataSet; 
   else 
   { 
     dataSet = new DataSet(); 
     dataSet.Tables.Add( dataTable ); 
   } 
 }   
 dbAdapter.Update( dataSet );
------解决方案--------------------ds.Tables.Add( DataGridView实例.DataSource); 
 dbAdapter.Update(ds);
------解决方案--------------------DataTable dt = DataGridView实例.DataSource as DataTable 
 ds.Tables.Add( dt.Copy() ); 
 dbAdapter.Update(ds);   
------解决方案--------------------DataTable dt = (System.Data.Datatable)DataGridView.DataSoruce  
 ds.Tables.Add( dt.Copy() ); 
 dbAdapter.Update(ds);