當我按Tab鍵未選擇下一個文本框

Question

我有一些文本框，我安排了TabIndexes但是。當我從textbox1到textbox2 TAB，我想textbox2中的文本被選中。我嘗試過：

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

但它不起作用。我怎樣才能做到這一點 ？

Answer 1

試試這個：

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

Answer 2

如何對焦點事件或事情TextBox.SelectAll()。

Answer 3

有一個名爲事件輸入文本框上，在這種情況下選擇begining（0）結束（文字lenght）文本

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

Answer 4

你應該選擇文本時，文本框得到了焦點。

在WPF中，您應該對GotKeyboardFocus事件做出反應。
在Winforms中，您應該對GotFocus事件做出反應。

在這兩種情況下，要執行的代碼只是textbox2.SelectAll();而不檢查製表符。

Answer 5

在Windows窗體和WPF：

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

在ASP.Net：

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

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Answer 6

我在Windows窗體和同樣的問題，vb.net （它可能很容易轉換爲C＃），我通過以下方式解決它：

1.將窗體KeyPreview屬性設置爲true。

獲取或設置一個值，該值指示表單在事件傳遞給具有焦點的控件之前是否接收關鍵事件。

這允許您僅針對表單而不是針對每個文本框處理關鍵事件。顯然，如果你只有一個文本框，這將節省你的工作。

2.處理窗體KeyUp事件

它看起來像KeyDown和則KeyPressed事件不火Tab鍵，但意外的是，KEYUP呢......

我離開你了代碼我在KeyUp事件中使用：

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 

我也給你我的「GetAllTextBoxes」功能，它可能可能不是最有效的方式，但它的工作原理。

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 

希望這有助於別人;）