Purpose: This Windows Desktop application allows the user to enter a height and weight and computes the user$$s body mass index. Program Procedures: The user will enter a height and weight using either the imperial or metric system. Algorithms, Processing, and Conditions: The user first views a Windows application that displays a title, a BMI graphic, a ListBox object to select the imperial or metric system, and labels to enter information for the user$$s height and weight. When the user selects imperial or metric and enters the height and weight, the Compute BMI button can be selected. This button should be disabled until the user enters a value for both the height and weight and selects a system. Hint: There is an event that can be used to execute code when the user tabs out of a control. Do not validate the data in these event procedures, only verify that the value was entered or selected. Call a separate sub procedure in each event procedure to determine if all data has been entered$/$selected and enable the button. A Sub procedure should be called to handle the imperial and metric BMI calculations using the following formulas: BMI $=($Weight in Pounds $/($Height in Inches $*$ Height in Inches$))*703$ BMI $=$ Weight in Kilograms $/($Height in Meters $*$ Height in Meters$)$ Two Function procedures should be called from the Sub procedure in the item above based on the system selected. Each Function procedure will calculate the BMI for the appropriate system and return the Decimal value to the calling procedure. The original sub procedure will display the result. You cannot use variables declared outside of the function procedure. If you need data in the function, you must pass that data to the function as parameters. In other words, do not reference a variable decWeight that is declared outside of the function. If you need that variable's value, you must pass the variable as a parameter to the function.

This is my code

Public Class FrmBMIAPP

Private Const $\_$strImperial As String $=$ "Imperial"

Private Const $\_$strMetric As String $=$ "Metric"

Private Sub FrmBMIAPP$\_$Load$($sender As Object, e As EventArgs$)$ Handles MyBase.Load

lstMesurement.Items.Add$(\_$strImperial$)$

lstMesurement.Items.Add$(\_$strMetric$)$

Threading.Thread.Sleep$(5000)$

btnCalculate.Enabled $=$ False

End Sub

Private Sub ValidateUserInput$()$

btnCalculate.Enabled $=$ IsInputValid$()$

End Sub

Private Function IsInputValid$()$ As Boolean

Dim weightValid As Boolean $=$ Double.TryParse$($txtWeight$.$Text, New Double$())$

Dim heightValid As Boolean $=$ Double.TryParse$($txtHeight$.$Text, New Double$())$

Dim mesurementSelected As Boolean $=$ lstMesurement.SelectedItem IsNot Nothing

Return weightValid AndAlso heightValid AndAlso LstMesurement$\_$SelectedIndexChanged$()$ IsNot Nothing

End Function

Private Function LstMesurement$\_$SelectedIndexChanged$()$ As Object

Throw New NotImplementedException$()$

End Function

Private Sub BtnCalculate$\_$Click$($sender As Object, e As EventArgs$)$ Handles btnCalculate.Click

Try

Dim Weight As Decimal $=$ Decimal.Parse$($txtWeight$.$Text$)$

Dim Height As Decimal $=$ Decimal.Parse$($txtHeight$.$Text$)$

Dim bmi As Decimal

If lstMesurement.SelectedItem.ToString$()=\_$strImperial Then

bmi $=$ CalculateBMIImperial$($CDec$($Weight$),$ CDec$($Height$))$

Else

bmi $=$ CalculateBMIMetric$($CDec$($Weight$),$ CDec$($Height$))$

End If

lblResults.Text $=$ "Your BMI is: $"$ & Math.Round$($bmi$,2).$ToString$()$

Catch ex As Exception

MessageBox.Show$("$Please enter Valid Numeric values for height and weight.", "Invalid Input", MessageBoxButtons.OK$,$ MessageBoxIcon.Error$)$

End Try

End Sub

Private Function CalculateBMIImperial$($ByVal Weight As Decimal, ByVal Height As Decimal$)$ As Decimal

Return $($Weight $/($Height $*$ Height$))*703$

End Function

Private Function CalculateBMIMetric$($ByVal Weight As Decimal, ByVal Height As Decimal$)$ As Decimal

Return Weight $/($Height $*$ Height$)$

End Function

Private Sub TxtHeight$\_$Leave$($sender As Object, e As EventArgs$)$ Handles txtHeight.Leave

ValidateUserInput$()$

End Sub

Private Sub TxtWeight$\_$Leave$($sender As Object, e As EventArgs$)$ Handles txtWeight.Leave

ValidateUserInput$()$

End Sub

Private Sub LstMesurement$\_$SelectedIndexChanged$($sender As Object, e As EventArgs$)$ Handles lstMesurement.SelectedIndexChanged

ValidateUserInput$()$

txtHeight.Text $=""$

txtWeight.Text $=""$

lblResults.Text $=""$

End Sub

Private Sub BtnExit$\_$Click$($sender As Object, e As EventArgs$)$ Handles btnExit.Click

Close$()$

End Sub

End Class

My issue is that my code is not working correctly. When the form runs the user is able to enter the height and weight in the text boxes but when the calculate button is clicked nothing happens. Please help