GUI - 文本框循环中的数字不起作用

Question

Public Class Form1
Public digits As String = "0123456789"
Public userInput As String
Public digitCount As Integer = 0
Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
    userInput = Console.ReadLine()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    For Each i As Char In userInput
        If digits.Contains(i) Then digitCount += 1
    Next
End Sub
Private Sub Label1_Click(sender As Object, e As EventArgs) Handles Label1.Click
End Sub

Private Sub MaskedTextBox1_MaskInputRejected(sender As Object, e As MaskInputRejectedEventArgs) Handles MaskedTextBox1.MaskInputRejected
End Sub

结束类

我的循环应该是什么，因为这个循环不起作用，在我的屏蔽文本框中输入我的数字计数的语法是什么

Answer 1

将循环替换为以下简单语句：

digitCount = userInput.Count(Function(c) Char.IsDigit(c))

注意：需要引用 System.Linq，默认情况下存在。