如何禁用文本框内的某些字符串？

Question

我按照以下代码所做的操作显示文本框内的所有数据都被禁用。

Private Sub chkSTC_CheckedChanged(sender As Object, e As System.EventArgs) Handles chkSTC.CheckedChanged 
     Select Case chkSTC.Checked 
      Case True 
       txtCargoDescription.Enabled = False 

      Case False 
       txtCargoDescription.Enabled = True 

     End Select 
    End Sub 

End Class 

如何从文本框中仅禁用某个字符串，即"1 X 40 HQ STC"。我应该添加什么？

请参考此图片：

谢谢先进！

Answer 1

您只能禁用控件。您不能禁用控件中的字符串。您可以做的最好的事情是编写事件处理程序（例如OnChange），如果它将导致字符串被修改，则会取消该事件。但更常见的解决方案是将字符串放在单独的控件中。

Answer 2

您不能禁用文本框内的字符串，但可以防止用户在该字符串内进行更改。例如，如果用户试图添加一个字符，请删除或在该字符串内进行任何更改，不要让它们发生。

我这样做：

Private Sub TextBox1_KeyUp(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyUp 
    'see if any change is made between the first 13 characters (13 characters because "1 X 40 HQ STC" had 13 chars) 
    If sender.selectionstart <= 14 Then 

     'see if a character is deleted (tried to press backspace or delete key) 
     If e.KeyCode = 8 Or e.KeyCode = 46 Then 
      'replace the first 12 characters with our orignal text 
      TextBox1.Text = TextBox1.Text.Replace(TextBox1.Text.Substring(0, 12), "1 X 40 HQ STC") 
      'if left or right key is pressed 
     ElseIf e.KeyCode = Keys.Left Or e.KeyCode = Keys.Right Then 
      'do nothing 
     ElseIf e.KeyCode = Keys.Enter Then 
      TextBox1.Text = TextBox1.Text.Replace(TextBox1.Text.Substring(0, 15), "1 X 40 HQ STC") 
     Else 
      'it means other text is added, remove 14 characters and put our original string 
      TextBox1.Text = TextBox1.Text.Replace(TextBox1.Text.Substring(0, 14), "1 X 40 HQ STC") 
     End If 
     'set the cursor to 15th character, i.e. next line 
     sender.selectionstart = 15 

    End If 
End Sub 

Answer 3

写入数据验证程序，取消“1×40 HQ STC”，这样只希望可以显示的字符串。