我正在使用.NET Framework 4.0使用VB开发VS 2010
我有combobox。它有一些项目，显示得很好。这里有点奇怪：
如果我点击combobox上的下拉箭头并点击我想要的项目，则会调用SelectedIndexChanged - 很好。
如果我在combobox的文本区域内单击并开始键入我想要的内容并按向上（或向下）键完成，则调用SelectedIndexChanged - 也很好。
如果我点击combobox上的下拉箭头并开始输入我想要的内容并按ENTER键完成，则不会调用SelectedIndexChanged - 问题。
在最后一种情况下，ENTER会导致不同的事件吗？我已尝试使用TextChanged和TextUpdate事件，但这些事件似乎不起作用：
Private Sub cmbStatus_TextChanged(sender As System.Object, e As System.EventArgs) Handles cmbStatus.TextChanged
If e.Equals(Keys.Enter) Then
Call SomeMethod()
End If
我应该使用e.Equals(Keys.Enter)以外的其他内容吗？
我还应该寻找其他事件吗？
修改
ComboBox中的项目示例如下：
---> this is the most common type ---> there are a few with '/' ---> there are a few with '(' and ')' 基本上，每个列表的类型是“## - SOME TEXT”。
答案 0 :(得分：6)
免责声明：这是用C＃编写的 - 如果您需要将其翻译成VB，请告诉我。
private void comboBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
//It's important to also check that the Combo Box is displaying its Drop Down. If
//you want this to execute even when it is not displayed, remove the check for
//comboBox1.DroppedDown.
if (e.KeyCode == Keys.Enter && comboBox1.DroppedDown &&
!string.IsNullOrEmpty(comboBox1.Text))
{
int index;
//Attempt to locate the string typed in by the user. An index of -1
//means it was not found.
if ((index = comboBox1.FindStringExact(comboBox1.Text)) != -1)
{
//Update the SelectedIndex.
comboBox1.SelectedIndex = index;
}
}
}
有趣的是，docs表示在处理用户所做的选择更改时，我们应该使用SelectionChangeCommitted事件而不是SelectedIndexChanged事件。在这种情况下有必要这样做，因为SelectedIndexChanged事件使用我的方法触发两次。
修改
要防止用户输入整个字符串，请使用Adi答案中的建议：转到组合框的属性并将AutoCompleteMode设置为SuggestAppend和AutoCompleteSource到ListItems - 我在创建答案时实际使用了这些设置，因此它应该适合你。
答案 1 :(得分：4)
Private Sub ComboBox1_KeyUp(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyUp
If e.KeyCode = Keys.Enter Then
MessageBox.Show(ComboBox1.SelectedText)
Call SomeMethod()
End If
End Sub
答案 2 :(得分：4)
Option Strict On
Public Class Form1
Friend WithEvents ComboBox1 As New ComboBox With {.Parent = Me}
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
ComboBox1.Items.AddRange({"hello", "tes1ted", "word", "item", "tes2ted"})
ComboBox1.Text = ComboBox1.Items(0).ToString
End Sub
Private Sub ComboBox1_KeyUp(ByVal sender As Object, ByVal e As KeyEventArgs) Handles ComboBox1.KeyUp
'You can put this in the keydown event, or adapt it a small bit and put it in the keypress event
'putting it in the textchanged event is problematic and not recommended.
Dim OriginalText As String = ComboBox1.Text
If e.KeyCode = Keys.Enter Then
If ComboBox1.SelectionLength > 0 Then
ComboBox1.Text = ComboBox1.Text
ComboBox1.SelectionLength = 0
ComboBox1.SelectionStart = ComboBox1.Text.Length
End If
End If
If Not IsTextKey(e.KeyCode) Then Exit Sub
Dim Filter As String = ComboBox1.Text & "*"
If Filter.Length = 1 Then Exit Sub
For I = 0 To ComboBox1.Items.Count - 1
If LCase(ComboBox1.Items(I).ToString) Like LCase(Filter) Then
ComboBox1.SelectedItem = ComboBox1.Items(I)
ComboBox1.Select(OriginalText.Length, (ComboBox1.Text.Length - OriginalText.Length))
Exit Sub
End If
Next
End Sub
Function IsTextKey(ByVal Key As Integer) As Boolean
Select Case True
Case Key = Keys.Up : Return False
Case Key = Keys.Down : Return False
Case Key = Keys.Left : Return False
Case Key = Keys.Right : Return False
Case Key = Keys.Back : Return False
Case Key = Keys.Delete : Return False
Case Key = Keys.LWin : Return False
Case Key = Keys.RWin : Return False
'add whatever I missed
'return false if the key either removes text from the textbox
'or does not produce a character
Case Else
'return true if the key produces a visible character(including space)
Return True
End Select
End Function
End Class
答案 3 :(得分：3)
我认为您应该将AutoCompleteMode设置为 SuggestAppend ，将AutoCompleteSource设置为 ListItems 。这样，如果您输入的内容与ComboBox中加载的项目一致，通过写下来并找到该项目，当按下 Enter 时，SelectedIndexChanged将被触发（即使找不到匹配项 - 列表中的第一个将被选中）
我已准备好something向你指出这一点。
此致
Adi Konstantin
答案 4 :(得分：2)
订阅KeyPressed活动：
Private Sub yourComboBox_KeyPressed(sender As System.Object, e As System.KeyPressedEventArgs) Handles yourComboBox.KeyPressed
If e.KeyChar.Equals((char)Keys.Enter) Then
Call SomeMethod()
End If
答案 5 :(得分：2)
这将有助于解决您的问题
Private Sub ComboBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyDown
If e.KeyCode = Keys.Enter Then
MsgBox("hello")'call some functions
End If
End Sub
答案 6 :(得分：2)
如果这对你有用，你能告诉我吗？
Private Sub ComboBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles ComboBox1.KeyPress
If e.KeyChar = Chr(13) Then
ComboBox1_SelectedIndexChanged(sender, e)
End If
End Sub
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
MsgBox(ComboBox1.Text)
'Your code here
End Sub
答案 7 :(得分：2)
当组合框下拉式设置为简单时，自动完成设置为追加，从我的列表项中获取，我遇到了类似的问题。我的解决方法是在每个textchanged事件上都有一个字符串变量保存组合框文本。这样，当按下ENTER时，您可以检索已删除的文本并将其重新分配给组合框文本。
＆＃39;全球声明
'Global declaraion
dim selected_text as string = ""
Private Sub combobox_textchanged(sender As Object, e As EventArgs) Handles combobox.TextChanged
If combobox.Text IsNot Nothing And combobox.Text <> "" Then
selected_text = combobox.Text
End If
End Sub
Private Sub combobox_keydown(sender As Object, e As KeyEventArgs) Handles combobox.KeyDown
If e.KeyCode = Keys.Enter Then
combobox.Text = selected_text
'put logic here
End If
End Sub
上面有一些很好的答案，但我喜欢我不需要整理所有的命令键和箭头等。
答案 8 :(得分：0)
在PreviewKeyDown事件上手动关闭列表：
Private Sub cmbStatus_PreviewKeyDown(sender As ComboBox, e As PreviewKeyDownEventArgs) Handles cmbStatus.PreviewKeyDown
If e.KeyCode = Keys.Enter Then sender.DroppedDown = False
End Sub