Question

当我尝试添加integer.tryparse来处理无效输入以及消息读取＆＃34;无效输入＆＃34;时，似乎无法使我的代码正常工作。例如，如果数字是字母而不是数字。以下是我到目前为止的情况：

Public Class Form1

    Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
        Answer.Text = ""
    End Sub

    Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
        Dim iNum, iSum As Double
        Dim isPrime As Boolean = False
        iNum = Integer.Parse(TextBox1.Text)
        For i = 2 To Math.Sqrt(iNum) Step 1
            iSum = iNum Mod i
            If (iSum = 0) Then
                isPrime = True
                Exit For
            End If
        Next
        If isPrime Then
            Answer.Text = "Is Not Prime"
        Else
            Answer.Text = "Is Prime"
        End If
    End Sub


End Class

Answer 1

这应该这样做：

Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
    Dim iNum, iSum As Double
    Dim isPrime As Boolean = False
    If Not Integer.TryParse(TextBox1.Text, iNum)
        Answer.Text = "invalid input"
    Else
        For i = 2 To Math.Sqrt(iNum) Step 1
            iSum = iNum Mod i
            If (iSum = 0) Then
                isPrime = True
                Exit For
            End If
        Next
        If isPrime Then
            Answer.Text = "Is Not Prime"
        Else
            Answer.Text = "Is Prime"
        End If
    End If
End Sub

VB。素数检查器。输入无效

1 个答案: