show message box for those textboxes which are empty

Question

I've some textboxes in my win form. On submit button I want to check if all the textboxes are filled or not. I want to show message for only those textboxes which are empty.

For eg.

First Name >> txtbox_FirstName

Last Name >> txtbox_LastName

Middle Name >> txtbox_MiddleName

Address >> txtbox_Address

Class >> txtbox_Class

private void btnSubmit_Click(object sender, EventArgs e)

{

if (txtbox_FirstName.Text == "" || txtbox_LastName.Text == "" || txtbox_MiddleName.Text == "" || txtbox_Address.Text == "" || txtbox_Class.Text == "")

{

MessageBox.Show( MessageBoxButtons.OK, MessageBoxIcon.Information);

// focus on the empty text boxes

}

In the message box I want to say to the user, please fill the text box which is empty.

Suppose, if the user has not fill txtbox_LastName, the message should be "please enter Last Name"

if the user has not fill txtbox_FirstName and txtbox_Class, the message should be "please enter First Name and Class".

And also focus on the first empty text box.

How can I do that?