如何使用字符串以不同的顺序显示名称？

Question

我遇到了分配给我的 Visual Basic 2012 课程的问题。说明如下。到目前为止，我只显示输入的名字，没有别的。如何让它按请求的顺序显示名字和姓氏？

字符串问题：在文本框中输入您的名字和姓氏。取名字并将其显示在一个标签框中，显示姓氏、名字。

文本框条目：Jane Doe

标签框：Doe, Jane

我到目前为止的代码如下。感谢您的帮助！

Private Sub btndisplay_Click(sender As Object, e As EventArgs) Handles btndisplay.Click
    Dim fullname As String
    Dim firstname As String
    Dim indexnum As Integer
    Dim lastname As String

    fullname = fulltextbox.Text

    indexnum = fullname.IndexOf(" ")

    firstname = fullname.Substring(0, indexnum)

    firstlabel.Text = firstname
    fulltextbox.Focus()
End Sub

Private Sub fulltextbox_TextChanged(sender As Object, e As EventArgs)
    firstlabel.Text = String.Empty

    fulltextbox.SelectAll()
End Sub

Private Sub btnexit_Click(sender As Object, e As EventArgs) Handles btnexit.Click
    Me.Close()
End Sub

Answer 1

首先确定空间的位置是正确的：

indexnum = fullname.IndexOf(" ")

现在基于这个索引，你可以将字符串拆分成两个字符串，firstname和lastname：

firstname = fullname.Substring(0, indexnum)
lastname = fullname.Substring(indexnum+1)

您需要使用indexnum+1，而不是indexnum，否则会包含空格字符。

最后，您使用string concatenation operator (&) 再次将它们组合在一起：

firstlabel.Text = lastname & ", " & firstname

---

最终的方法如下所示：

Private Sub btndisplay_Click(sender As Object, e As EventArgs) Handles btndisplay.Click
    Dim fullname As String
    Dim firstname As String
    Dim indexnum As Integer
    Dim lastname As String

    fullname = fulltextbox.Text

    indexnum = fullname.IndexOf(" ")

    firstname = fullname.Substring(0, indexnum)
    lastname = fullname.Substring(indexnum+1)

    firstlabel.Text = lastname & ", " & firstname
    fulltextbox.Focus()
End Sub

Answer 2

请注意，如果您使用中间名首字母，这将不起作用。另外，我会从fulltextbox_TextChanged 中删除fulltextbox.SelectAll()

Private Sub btndisplay_Click(sender As Object, e As EventArgs) Handles btndisplay.Click

    Dim Names() As String = fulltextbox.Text.Split(" "c)

    If Names.Count = 2 Then
        firstlabel.Text = Names(1) + ", " + Names(0)
    ElseIf Names.Count = 0 Then
        MessageBox.Show("Please enter name.")
    Else
        MessageBox.Show("Invalid Nmae entered.")
    End If

    fulltextbox.Text = ""

End Sub