vb.net - 需要 TryParse 的 Visual Basic 程序

Question

我正在尝试使用 VisualBasic 在 VisualStudio 中创建一个更大或更小的程序。我是编码新手，我不确定如何将 TryParase 添加到我的代码中以使其工作。我需要它来验证是否输入了整数并在输入整数以外的内容时显示错误消息。

Private Sub btnCompare_Click(sender As Object, e As EventArgs) Handles btnCompare.Click
        Dim number1 As Double
        Dim number2 As Double

        number1 = Convert.ToDouble(TextBox1.Text)
        number2 = Convert.ToDouble(TextBox2.Text)

        If number1 < number2 Then
            TextBox3.Text = "Value B is greatest"
        End If
        If number1 > number2 Then
            TextBox3.Text = "Value A is greatest"
        End If
        If number1 = number2 Then
            TextBox3.Text = "Value A and B are the same"
        End If
        If TryParse(TextBox1.Text, number1) Then
            TextBox3.Text = "ERROR: User did not enter an Integer"
        End If
    End Sub
End Class

标签： vb.net

Answer 1

Private Sub btnCompare_Click(sender As Object, e As EventArgs) Handles btnCompare.Click
    Dim number1 As Integer
    Dim number2 As Integer

    If Not Integer.TryParse(TextBox1.Text, number1) OrElse
       Not Integer.TryParse(TextBox2.Text, number2) Then
        TextBox3.Text = "ERROR: User did not enter an Integer"            
    ElseIf number1 < number2 Then
        TextBox3.Text = "Value B is greater"
    ElseIf number1 > number2 Then
        TextBox3.Text = "Value A is greater"
    Else
        TextBox3.Text = "Values A and B are the same"
    End If
End Sub

您还会注意到那里还有许多其他改进，例如使用正确的数据类型 ieInteger而不是Double. 我认为从您的错误消息中这是正确的。我还纠正了你缺乏Else陈述的情况。