VB重量计算器中的语法

Question

我正在编写一个非常简单的体重计算器代码-用户输入体重和身高，我计算该身高的标准体重，然后代码根据if / elseif块中的标准将该体重与体重范围进行比较。

可以正确返回标准重量，但是无论高度与重量之比如何，代码始终返回“正常重量”。 我是VB的新手，所以我的直觉是这是一个相对简单的语法问题。

  Dim dbHeight, dbWeight, dbStWeight As Double
    dbHeight = CDbl(tbxHeight.Text)
    dbWeight = CDbl(tbxWeight.Text)
    dbStWeight = (dbHeight * 30.48 - 105) / 0.454
    lblFeedback.Text = ("Your standard weight is " & dbStWeight)

    If (dbStWeight * 0.9 <= dbWeight <= dbStWeight * 1.1) Then
        lblResult.Text = ("Normal Weight")

    ElseIf (dbStWeight * 1.1 < dbWeight <= dbStWeight * 1.2) Then
        lblResult.Text = ("Over Weight")

    ElseIf (dbStWeight * 0.8 <= dbWeight < dbStWeight * 0.9) Then
        lblResult.Text = ("Under Weight")

    ElseIf (dbWeight > dbStWeight * 1.2) Then
        lblResult.Text = ("Very overweight")

    ElseIf (dbWeight < dbStWeight * 0.8) Then
        lblResult.Text = ("Very underweight")

    End If
    lblFeedback.Refresh()
    lblResult.Refresh()

Answer 1

 Private Sub btOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btOK.Click

    Dim dbHeight, dbWeight, dbStWeight As Double
    dbHeight = CDbl(tbxHeight.Text)
    dbWeight = CDbl(tbxWeight.Text)
    dbStWeight = (dbHeight * 30.48 - 105) / 0.454
    StWeight.Text = ("Your standard weight is " & dbStWeight)

    If (dbStWeight * 0.9 <= dbWeight) AndAlso (dbWeight <= dbStWeight * 1.1) Then
        Result.Text = ("Normal Weight")

    ElseIf (dbStWeight * 1.1 <= dbWeight) AndAlso (dbWeight <= dbStWeight * 1.2) Then
        Result.Text = ("Overweight")

    ElseIf (dbStWeight <= dbWeight) AndAlso (dbWeight < dbStWeight * 0.9) Then
        Result.Text = ("Underweight")

    ElseIf (dbWeight > dbStWeight * 1.2) Then
        Result.Text = ("Very overweight")

    ElseIf (dbWeight < dbStWeight * 0.8) Then
        Result.Text = ("Very underweight")

    End If

End Sub