c# - 当我按 TAB 时，未选择下一个文本框

Question

我有一些文本框，我安排了 TabIndexes BUT。当我从textbox1to选项卡时textbox2，我希望选择文本textbox2。我试过了：

if (e.KeyCode == Keys.Tab)
{
   textbox2.SelectAll();
}

但它不起作用。我怎样才能做到这一点 ？

Answer 1

焦点事件上的TextBox.SelectAll()怎么样。

Answer 2

TextBox上有一个名为Enter的事件，在此事件中选择从开始（0）到结束（文本长度）的文本

private void textBox2_Enter(object sender, EventArgs e)
{
    textBox2.SelectionStart = 0;
    textBox2.SelectionLength = textBox2.Text.Length;
    //or also
    //textBox2.SelectAll()
}

Answer 3

在 Windows 窗体和 WPF 中：

 textbox.SelectionStart = 0; textbox.SelectionLength =
 textbox.Text.Length;

在 ASP.Net 中：

textBox.Attributes.Add("onfocus","this.select();");

更多详情请点击这里

Answer 4

当文本框获得焦点时，您应该选择文本。

在 WPF 中，您应该对GotKeyboardFocus事件做出反应。
在 Winforms 中，您应该对GotFocus事件做出反应。

在这两种情况下，要执行的代码都不textbox2.SelectAll();需要检查 tab 键。

Answer 5

我在 Windows Forms 和 vb.net 中遇到了同样的问题（它可能很容易转换为 c#），我通过以下方式解决了它：

1. 将表单 KeyPreview 属性设置为 true。

获取或设置一个值，该值指示在将事件传递给具有焦点的控件之前窗体是否将接收键事件。

这允许您只为表单而不是为每个文本框处理键事件。显然，如果您只有一个文本框，这将不会为您节省任何工作。

2.处理表单KeyUp事件

看起来 KeyDown 和 KeyPressed 事件不会为 Tab 键触发，但出乎意料的是，KeyUp 确实...

我留下我在 KeyUp 事件中使用的代码：

Private Sub MyForm_KeyUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyUp
    // Do nothing if key other than TAB is pressed
    If Not e.KeyCode = Keys.Tab Then Exit Sub

    // Search for the control that currently has the focus
    // As we are only interested in doing something when the focus is in textboxes, we do not even search the focus for other controls
    Dim focused_textbox As TextBox = Nothing
    For Each p As TextBox In GetAllTextBoxes(Me) //GetAllTextBoxes is a function that gets a list with all the textboxes for the form passed as a parameter.
        If p.Focused Then
            focused_textbox = p
            Exit For
        End If
    Next

    // If no textbox has the focus, no actions are required.
    If focused_textbox Is Nothing Then Exit Sub

    // If the textbox with the focus does not have any content, nothing is to be selected....
    If String.IsNullOrEmpty(focused_textbox.Text) Then Exit Sub

    // select all the textbox contents
    focused_textbox.SelectAll()
    /* I've also seen arroun the following sollution, instead of the 'focused_textbox.SelectAll()', but I have not tried it, as SelectAll worked perfect for me
    focused_textbox.SelectionStart = 0
    focused_textbox.SelectionLength = focused_textbox.Text.Length
    */
End Sub

我还给你我的“GetAllTextBoxes”函数，它可能不是最有效的方法，但它确实有效。

Function GetAllTextBoxes(ByVal control_or_form As Object) As List(Of TextBox)
    Dim l As List(Of TextBox) = New List(Of TextBox)

    // Fill control_collection with child controls of the control_or_form 
    Dim control_collection As List(Of Control) = New List(Of Control)
    If TypeOf control_or_form Is Windows.Forms.Form Then
        Dim form As Windows.Forms.Form = CType(control_or_form, Windows.Forms.Form)
        If form.HasChildren Then
            For Each c As Control In form.Controls
                control_collection.Add(c)
            Next
        Else
            Return l
        End If
    ElseIf TypeOf control_or_form Is Windows.Forms.Control Then
        Dim control As Windows.Forms.Control = CType(control_or_form, Windows.Forms.Control)
        If control.HasChildren Then
            For Each c As Control In control.Controls
                control_collection.Add(c)
            Next
        Else
            Return l
        End If
    Else
        Return l
    End If

   // At this point if control_or_form is not a control or a form, or if it has no children, the function had already returned an empty list meaning 'this object has no child textboxes'
   // Now, for all the child controls, store them into the list if they are TextBoxes and, if not, search more TextBoxes within its childs if it has any.
    For Each child_c As Control In control_collection
        If TypeOf child_c Is TextBox Then
            l.Add(child_c)
        End If

        If child_c.HasChildren Then
            l.AddRange(GetAllTextBoxes(child_c)) //Here we see why this function needs to allow input form and control at the same time 
        End If
    Next

    Return l
End Function

希望这可以帮助某人；）

Answer 6

尝试这个：

textbox2.SelectionStart = 0;
textbox2.SelectionLength = textbox2.Text.Length;