Why this DataBinding does not work?

Question

I really don't know why this doesn't update the database, Anyone can help me?

 SetMasteraAdapter(clsLabWork.LabWorkMaster, "LabTestMaster"); 
dtaMaster.UpdateCommand = new SqlCommandBuilder(dtaMaster).GetUpdateCommand(); 
txtLabNo.DataBindings.Add(new Binding("Text", dtsMaster, "LabTestMaster.LabNo")); 
txtSaleMan.DataBindings.Add(new Binding("Text",dtsMaster, "LabTestMaster.SaleMan")); 
txtSaleMan.Text  = "Jack"; 
dtaMaster.Update(dtsMaster, "LabTestMaster");