vb.net - For each textbox loop

Question

I'm trying to make a foreach loop that checks every TextBox in a panel and changes BackColor if its Text is nothing. I've tried the following:

Dim c As TextBox
For Each c In Panel1.Controls
  if c.Text = "" Then
    c.BackColor = Color.LightYellow
  End If
Next

but I'm getting the error:

Unable to cast object of type System.Windows.Forms.Label to type System.windows.forms.textbox

Answer 1

Assuming there are no nested controls:

For Each c As TextBox In Panel1.Controls.OfType(Of TextBox)()
  If c.Text = String.Empty Then c.BackColor = Color.LightYellow
Next