如何使用字符串以不同顺序显示名称？

Question

我遇到了我分配给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。我怎样才能让它显示所请求的序列中的名字和姓氏？

String问题：在文本框中输入您的名字和姓氏。取名称并将其显示在显示姓氏，名字的标签框中。

文本框输入：李四

标签框：DOE，简

我到目前为止的代码如下。谢谢你的帮助！

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

你是在正确的轨道上，首先确定在空间位于：

indexnum = fullname.IndexOf(" ") 

现在基于该指标，可以将字符串分割成两个字符串，firstname和lastname：

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

您需要使用indexnum+1而不是indexnum，否则您将包含间距字符。

最后，你组在一起再次使用string concatenation operator (&)：

firstlabel.Text = lastname & ", " & firstname 

---

的最后一个方法因而看起来像：

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

注意，这也不会，如果你的使用中工作缩写。此外，我会从删除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