[sooriaty03]

وعليكم السلام
أخي الكريم
جرب هذا الكود

كود :

Private Sub TextBox1_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.LostFocus
        TextBox1.Focus()
    End Sub

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        TextBox1.TabIndex = 0
    End Sub