I'm facing problems troubleshooting my vb.net code

I'm trying to update data in my excel database but it keeps giving me an error "Cannot covert from string "" to integer". I guess there is something wrong with it as I am not good with vb.net. I'm using an excel database. Only the first combox1 part is working without any error.

 Dim AreaCode As String
    Dim x As Integer
    MsgBox("Do you want to update the records?")
    If ComboBox1.SelectedIndex.Equals(0) Then
        Try
            AreaCode = ACTextBox.Text
            DataGridView.Rows.Item(x).Cells(0).Value = ACTextBox.Text
        Catch ex As Exception
            MsgBox(ex.Message.ToString)
        End Try
    End If

    Dim MetropolitanArea As String
    If ComboBox1.SelectedIndex.Equals(1) Then
        Try
            MetropolitanArea = MATextBox.Text
            DataGridView.Rows.Item(x).Cells(1).Value = ACTextBox.Text
        Catch ex As Exception
            MsgBox(ex.Message.ToString)
        End Try
    End If

    Dim AnnualFixedArea As Integer
    If ComboBox1.SelectedIndex.Equals(2) Then
        Try
            AnnualFixedArea = AFCTextBox.Text
            DataGridView.Rows.Item(x).Cells(2).Value = AFCTextBox.Text
        Catch ex As Exception
        End Try
    End If

    Dim WagePerHour As String
    If ComboBox1.SelectedIndex.Equals(3) Then
        Try
            WagePerHour = TextBoxWPH.Text
            DataGridView.Rows.Item(x).Cells(3).Value = TextBoxWPH.Text
        Catch ex As Exception
            MsgBox(ex.Message.ToString)
        End Try
    End If
End Sub