从目标字符串 VB.NET 中随机选择

Question

我是怎么做到的

Source_Source.Text（富文本框）：

src="test.com"akalsjdjalksdv src="another.com"asdbnmslkbjcxv asdas as danms d amsn asdasd src="cold.com"asdas as dasd amnbs dma d sdf kjhds f src="find.com" asd kja sdasjhk d asdsrc="other.com" a jksdh asksjd hasdjh src="found.com"

如果我想得到随机 src=" " 怎么办，例如，如果我点击 butten 将显示 message = src="test.com" ，如果我再次点击按钮将显示另一个随机，例如 src="another.com" ，

我目前的代码只选择第一个字符串 which = src="test.com" ，我想随机选择 src="[random test / cold / other / found / find]"

例如，我的下一次点击可以显示src="find.com" 的消息，例如。

我的代码：

 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim sSource As String = Source_Source.Text 'String that is being searched
    Dim sDelimStart As String = Search_1.Text 'First delimiting word
    Dim sDelimEnd As String = Search_2.Text  'Second delimiting word
    Dim nIndexStart As Integer = sSource.IndexOf(sDelimStart) 'Find the first occurrence of f1
    Dim nIndexEnd As Integer = sSource.IndexOf(sDelimEnd, nIndexStart + sDelimStart.Length + 1) 'Find the first occurrence of f2

    If nIndexStart > -1 AndAlso nIndexEnd > -1 Then '-1 means the word was not found.
        Dim res As String = Strings.Mid(sSource, nIndexStart + sDelimStart.Length + 1, nIndexEnd - nIndexStart - sDelimStart.Length) 'Crop the text between
         MessageBox.Show(res) 'Display
    Else
        MessageBox.Show("One or both of the delimiting words were not found!")
    End If
End Sub

Answer 1

Private Function RndUrl() As String
    Dim UrlStr() As String = {"whatever.com", "whatever2.com"}
    Return Rand.Next(0, UrlStr.Length) '"Rand" Declared at Class scope as Random
End Function

用法：

    TextBox1.Text = "src=""" & RndUrl() & ""

Answer 2

如果我正确理解您的问题，您是在寻找字符串中的某个短语吗？如果是这样，请查看 String.Contains() 方法。 例如：

If Source_Source.Text.Contains(Search_1.Text) Then
    ' Do you're logic here if found
    Source_Source.Text.SubString(0, 5) ' Or where ever that part of the string is that you want.
End If