How to disable a textbox and combo box by coding?

Impossible.
If you want to disable a control, you have to use "Enabled" property of a control. And it must be set to false.
Or you can even use "ReadOnly" property, which has to be set to true (to be disabled).

like this ?

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    TextBox1.Enabled = False
    ComboBox1.Enabled = False
End Sub

like this ?

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    TextBox1.Enabled = False
    ComboBox1.Enabled = False
End Sub

Exactly!! thanks!