Detect changes made to WindowsForms controls, C#

I need to detect the changes that were made to the form, either in TextBox, Datagridviewor other controls.

Here I leave a small example as a test code (GoogleDrive link)IdentificarCambios.zip

This works perfectly for me , but I think there should be a more optimal and practical method. I know that it Datasetcontains a method called HasChangesbut I don't know how to use it to get the result I want.

Here I start the explanation:

Here we see this form as you can see Boton Salvarit is disabled, because it is the original data initially loaded. If I make a change in any of these cells: Hora Entrada, Hora Salida, Cantidadafter the event is fired a call CellEndEditis invoked which works as follows:Funciónverificar_cambios

Initially when the data is loaded I have two datasetof which I copy the original dataset to the second dataset so that they contain the same data, then in the function Verificar_cambiosI perform the validation of whether the value found in it dataset originalis the same as that found in the otro datasetif is the same the botón Salvaris not enabled, otherwise the botón Salvaris enabled.

As you can see in the second image I have changed the value of the celdato 5function 10was invoked and enabled the botón salvar. But if usuariohe puts its value back into 5the function again deshabilitathe botón salvar. I don't know how to achieve that with HasChanges.

EDITED

Code Snippet:

When you load the data:

dataset_cambios = dataset_datos.Copy();

Check Changes function:

private void verificar_cambios()
{
     string cantidad = string.Empty cantidad_cambios = string.Empty;
     for (int fila = 0; fila < dataset_datos.Tables[0].Rows.Count; fila++)
     {
          if (dataset_datos.Tables[0].Rows[fila]["cantidad"].ToString() == string.Empty)
              cantidad = string.Empty;
          else
              cantidad = dataset_datos.Tables[0].Rows[fila]["cantidad"].ToString().Trim();

          if (dataset_cambios.Tables[0].Rows[fila]["cantidad"].ToString() == string.Empty)
              cantidad_cambios = string.Empty;
          else
          cantidad_cambios = dataset_cambios.Tables[0].Rows[fila]["cantidad"].ToString().Trim();

         //Verificando si la variable del dataset original es diferente a la del dataset guardado inicialmente. 
         if (cantidad.Equals(cantidad_cambios))
         {
             //No hay cambios
             btn_salvar.Enabled = false;
         }
         else
         {
             //Si hay cambios
             btn_salvar.Enabled = true;
             break;
         }
     }
  } 

So how do I optimize this method, or create a more efficient one?

Note: I have not placed all the code of the project so as not to enlarge the publication so much.

Visual Studio 2010 and the .NET Framework 4