DataGrid - Show Message When No Data Entered By User

I am trying to show message when user didn't enter any data in datagrid and click on save button it should display message please enter the required fields but I am using this code for this purpose.

For Each cell As DataGridViewCell In DataGridView1.Rows(DataGridView1.RowCount - 1).Cells
If cell.Value Is Nothing OrElse cell.Value.ToString = String.Empty Then
MessageBox.Show("Please Enter the Required Field(s)!", "ITPCHR", MessageBoxButtons.OK, MessageBoxIcon.Stop)
Exit Sub
[Code] .....

When I click on save button without entering data it give me message please enter the required fields but when I enter the data in datagrid it didn't save data and gives same message please enter the required fields.