[ali.alfoly]

جزاك الله خير
اريد منك تجربة الكود

كود :

Public Class Form1

    Private Sub Form1_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Activated
        Me.TextBox1.Text = "a"
    End Sub

    Private Sub Form1_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.LostFocus
        Me.TextBox1.Text = "b"
    End Sub
End Class