I am facing similar issue (http://es.infragistics.com/community/forums/t/27341.aspx)

Below are snippet from code:

this.usernameTextBox.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.userManagementDataSet, "users.username", true));

this.systemUsersGrid.DataMember = "users";
this.systemUsersGrid.DataSource = this.userManagementDataSet;

Now, the user creates a new user using the below code :

userManagementDataSet.users.AddusersRow("NU" + _newUserCount, string.Empty, 101, "New", "User", DateTime.Now, string.Empty, string.Empty);

The dataset is updated and same is shown in textbox.

The user after editing user data closes the form

the change is not committed to the db. Saving code:

_sysUsersDa.Update(userManagementDataSet.users)

I tried the below code to try to update grid data:

var userName = usernameTextBox.Text;

systemUsersGrid.Selected.Rows[0].Cells["username"].Value = userName;

systemUsersGrid.UpdateData();

But again nothing is saved

Please suggest