Enabling/Disabling buttons; button never enables (visual studio)

Current code:

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim Gold = CInt(TextBox1.Text)
    Dim Silver = CInt(TextBox2.Text) / 100
    Dim Copper = CInt(TextBox3.Text) / 10000
    Dim Result = (Gold + Silver + Copper) * 0.85
    Label1.Text = Result & " Gold"

End Sub

and

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    If (TextBox1.Text + TextBox2.Text + TextBox3.Text = "") Then
        Button1.Enabled = False
    Else
        Button1.Enabled = True
    End If
End Sub

How come whenever I start the program, and I enter numbers into textbox1, textbox2, and textbox3 the button does not get enabled?