vb.net 如何过滤我的组合框
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How to filter my combobox
提问by HymanSparrow
I have managed to filter my combobox so it filters and displays the correct records ie when A is typed all A records show, B is typed all B records show and so on. However it would it be possible to have a message box to display when no records is found in the combobox?
我设法过滤了我的组合框，以便它过滤并显示正确的记录，即当输入 A 时所有 A 记录显示，B 输入所有 B 记录显示等等。但是，是否可以在组合框中找不到记录时显示消息框？
The coding i have so far is :-
我到目前为止的编码是：-
Private Sub cmblogged_KeyPress(sender As Object, e As KeyPressEventArgs) Handles cmblogged.KeyPress
If Char.IsControl(e.KeyChar) Then Return
With Me.cmblogged
Dim ToFind As String = .Text.Substring(0, .SelectionStart) & e.KeyChar
Dim Index As Integer = .FindStringExact(ToFind)
If Index = -1 Then Index = .FindString(ToFind)
If Index = -1 Then Return
.SelectedIndex = Index
.SelectionStart = ToFind.Length
.SelectionLength = .Text.Length - .SelectionStart
e.Handled = True
End With
End Sub
回答by varocarbas
Achieving what you want with your code is straightforward, just convert If Index = -1 Then Returninto:
用你的代码实现你想要的很简单，只需转换If Index = -1 Then Return为：
If Index = -1 Then
MessageBox.Show("Not Found.")
Return
End If
In any case, note that there is an in-built functionality in ComboBoxperforming the same action which your code does right now: AutoCompleteModedifferent than Noneand AutoCompleteSourceset to ListItems. Logically, you can evolve your code to perform much more complex actions (what I guess that is the case), but I preferred to highlight this issue just in case.
在任何情况下，请注意，在ComboBox执行您的代码现在所做的相同操作时，有一个内置功能：AutoCompleteMode不同于None并AutoCompleteSource设置为ListItems。从逻辑上讲，您可以改进代码以执行更复杂的操作（我猜是这种情况），但我更愿意强调这个问题以防万一。
