数据更新问题，我在前台更新了数据，但在后台没有更改。。。！！！！！！！！

数据更新问题，我在前台更新了数据，但在后台没有更改。。。！！！！！！！！
private void btnSave_Click(object sender, System.EventArgs e)
{

try
{

// End the Current edit. if you do not do this, when the user makes a
// change and then clicks the Save button prior to stepping to another
// records, the changes will not be propagated.

this.BindingContext[dtEmployeeInfo].EndCurrentEdit();

// Update the database with the changes made to the local resident DataSet.

da.Update(this.dtEmployeeInfo);



MessageBox.Show("Database successfully updated.",
"Custom Formatting Handler Demo", MessageBoxButtons.OK,
MessageBoxIcon.Information);

}
catch(Exception exp)
{

MessageBox.Show("There was an error when attempting to update " +
"the database: " + exp.Message,
this.Text, MessageBoxButtons.OK,
MessageBoxIcon.Error);
}

}