如何响应WPF的ComboBox的输入事件？

[m_halfman]

没有TextChanged事件。
TextInput事件不响应。
KeyUp事件只响应第一次输入。

[光宇广贞]

哈哈……
终于碰上一个用WPF的了。

我告诉你一个最方便的方法。

你可以重写combobox的controltemplate

你用xamlpad查一下就知道

在combobox的视觉树里面，会有textbox，你响应它的textchanged事件就好了。

[修改一下昵称]

up

[insuya]

通过Combobox的视觉树找到TextBox就可以了哇，TextBox的Name是PART_EditableTextBox

[m_halfman]

视觉树怎么用？具体的写法有没有……

[光宇广贞]

如果你装了VS的话，那么在microsoft sdks\windows\v6.0下面你可以找到这个xamlpad程序，
用这个来查看视觉树。

重写controltemplate可以看MSDN，很全。

combobox里面textbox 的name是PART_EditableTextBox

[kissyou886]

可以试试OnPreviewTextInput事件，没有时间亲自试，帮顶

[冰与火的交融]

我是要靠这样搞定的：（vb.net）

#Region "TextChanged"
Private Sub UserName_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs) Handles UserName.KeyUp
UserNameTextChanged()
End Sub
Private Sub UserName_LostFocus(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles UserName.LostFocus
UserNameTextChanged()
End Sub
Private Sub UserName_PreviewTextInput(ByVal sender As Object, ByVal e As System.Windows.Input.TextCompositionEventArgs) Handles UserName.PreviewTextInput
UserNameTextChanged()
End Sub
Private Sub UserNameTextChanged()
If UserName.Text Is Nothing Then
Else
If UserName.Text.Trim = String.Empty Then
ButtonRemove.Visibility = Windows.Visibility.Hidden
Else
For Each Item In UserName.Items
If Item = UserName.Text.Trim Then
ButtonRemove.Visibility = Windows.Visibility.Visible
Else
ButtonRemove.Visibility = Windows.Visibility.Hidden
End If
Next
End If
End If
End Sub
#End Region

[冰与火的交融]

我是要靠这样搞定的：（vb.net）

#Region "TextChanged"
    Private Sub UserName_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs) Handles UserName.KeyUp
        UserNameTextChanged()
    End Sub
    Private Sub UserName_LostFocus(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles UserName.LostFocus
        UserNameTextChanged()
    End Sub
    Private Sub UserName_PreviewTextInput(ByVal sender As Object, ByVal e As System.Windows.Input.TextCompositionEventArgs) Handles UserName.PreviewTextInput
        UserNameTextChanged()
    End Sub
    Private Sub UserNameTextChanged()
        If UserName.Text Is Nothing Then
        Else
            If UserName.Text.Trim = String.Empty Then
                ButtonRemove.Visibility = Windows.Visibility.Hidden
            Else
                For Each Item In UserName.Items
                    If Item = UserName.Text.Trim Then
                        ButtonRemove.Visibility = Windows.Visibility.Visible
                    Else
                        ButtonRemove.Visibility = Windows.Visibility.Hidden
                    End If
                Next
            End If
        End If
    End Sub
#End Region

[capcom923]

我找到方法了：
第一种：如http://liuqi740924.blog.163.com/blog/static/803471542010834316688/
大哥所说

第二种：通过楼上的楼上的楼上的……所说的VisualTree，具体使用系统内置的VisualTreeHelper类

例如你想找this.cbStandards的TextBox控件，可如下索取
((TextBox)VisualTreeHelper.GetChild( (DependencyObject)(VisualTreeHelper.GetParent( (DependencyObject)this.cbStandards)),1))
你可以给这个东东加事件。