How Do I Add Numbers Together From A Listbox

Option Strict On

Public Class fmResurface
    Public Const dblWoodFlooring As Double = 5D
    Public Const dblCarpetFlooring As Double = 3D ' This class variable doesnt change and is available througout app'
    Dim dbldefaultWoodcost As Double
    Dim dbldefaultcarpetcost As Double
    Private Sub Label1_Click(sender As Object, e As EventArgs) Handles lblOutput.Click

    End Sub

    Private Sub Label1_Click_1(sender As Object, e As EventArgs) Handles lblOutputNumberRooms.Click

    End Sub

    Private Sub GroupBox1_Enter(sender As Object, e As EventArgs) Handles GBFloorType.Enter

    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        dbldefaultcarpetcost = dblCarpetFlooring
        dbldefaultWoodcost = dblWoodFlooring

    End Sub

    Private Sub Label1_Click_2(sender As Object, e As EventArgs) Handles Label1.Click

    End Sub

    Private Sub btnEnter_Click(sender As Object, e As EventArgs) Handles btnEnter.Click
        Dim strFirstName As String
        Dim strLastName As String
        Dim strRoomName As String
        Dim dblRoomWidth As Double = 0D
        Dim dblRoomLength As Double = 0D
        Dim dbltotalcost As Double = 0D
        Dim dblRoomsize As Double = 0D

        strFirstName = txtFirstName.Text
        strLastName = txtLastName.Text
        strRoomName = txtRoomName.Text
        lblOutput.Text = "Hello, " + txtFirstName.Text + ",the" + txtLastName.Text + " home estimate:"
        lblOutputNumberRooms.Text = "Total Number of Rooms:" + lbRoomName.Items.Count.ToString()
        For x = 0 To lbRoomName.Items.Count - 1
            dblRoomsize = dblRoomsize + (Val(lbRoomWidth.Items(x)) * Val(lbRoomLength.Items(x)))
        Next
        If RBCarpet.Checked = False And RBWoodFloor.Checked = False Then MessageBox.Show("Click Carpet or Wood Floors First!")
        If Not strFirstName <> "" And strLastName <> "" And dblRoomLength.ToString <> "" And strRoomName <> "" And dblRoomWidth.ToString <> "" Then
            MessageBox.Show("Enter data into boxes!")

            If dbldefaultcarpetcost = dblCarpetFlooring Then
                lbRoomName.Items.Add(txtRoomName.Text)
                lbRoomLength.Items.Add(txtRoomLength.Text)
                lbRoomWidth.Items.Add(txtRoomWidth.Text)
                lbTotalCost.Items.Add(dblRoomsize * dbldefaultcarpetcost)
                dbltotalcost = dblRoomsize * dbldefaultcarpetcost

            End If
        Else
            If dbldefaultWoodcost = dblWoodFlooring Then
                lbRoomName.Items.Add(txtRoomName.Text)
                lbRoomLength.Items.Add(txtRoomLength.Text)
                lbRoomWidth.Items.Add(txtRoomWidth.Text)
                lbTotalCost.Items.Add(dblRoomsize * dbldefaultWoodcost)
                dbltotalcost = dblRoomsize * dbldefaultWoodcost
            End If
        End If



        lblOutputSquareFootage.Text = " Total square footage: " + dblRoomsize.ToString("0.0")
        lblOutputCostResurface.Text = "Total cost to resurface: " + dbltotalcost.ToString("C")
    End Sub

    Private Sub lbTotalCost_SelectedIndexChanged(sender As Object, e As EventArgs) Handles lbTotalCost.SelectedIndexChanged

    End Sub

    Private Sub RBWoodFloor_CheckedChanged(sender As Object, e As EventArgs) Handles RBWoodFloor.CheckedChanged
        If RBWoodFloor.Checked Then pccarpet.Image = My.Resources.floor

    End Sub

    Private Sub RBCarpet_CheckedChanged(sender As Object, e As EventArgs) Handles RBCarpet.CheckedChanged
        If RBCarpet.Checked Then pccarpet.Image = My.Resources.nice


    End Sub

    Private Sub pccarpet_Click(sender As Object, e As EventArgs) Handles pccarpet.Click



    End Sub

    Private Sub lbRoomName_SelectedIndexChanged(sender As Object, e As EventArgs) Handles lbRoomName.SelectedIndexChanged

    End Sub

    Private Sub txtFirstName_TextChanged(sender As Object, e As EventArgs) Handles txtFirstName.TextChanged

    End Sub
End Class