检测文本框中的数字键 - VB.NET
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Detect Numeric Keys in Textbox - VB.NET
提问by Muhammad Saqib
I want to detect numeric keys of numpad in textbox keypress event, Actually I just want to allow user to enter numbers from numpad not from alphanumeric pad.
我想在文本框按键事件中检测数字键盘的数字键，实际上我只想允许用户从数字键盘而不是字母数字键盘输入数字。
If the numbers are not coming from numpad of the keyboard, event should be cancel.
如果数字不是来自键盘的小键盘，则应取消事件。
Is there any way except GetAsyncKeyState()to achieve this task?
除了GetAsyncKeyState()完成这个任务，还有什么办法吗？
Currently I'm trying this codes.
目前我正在尝试这些代码。
If e.KeyChar = Chr(49) Then '48 to 57 are the char codes for "0 to 9" of alphanumeric keypad.
e.Handled = True
End I
The use GetAsyncKeyState()is my last priority because it can decrease the performance of my application.
使用GetAsyncKeyState()是我最后的优先事项，因为它会降低我的应用程序的性能。
回答by Panagiotis Kanavos
There are two ways to check this
有两种方法可以检查这个
To check for specific keys instead of characters, use the KeyCodeproperty of the KeyDown/KeyUp events for values between Keys.NumPad0to Keys.NumPad9. KeyPress doesn't provide this property.
If (e.KeyCode >= Keys.NumPad0 and e.KeyCode <= Keys.NumPad9) Then ...If you want to check whether a character is a numeric digit, you can use Char.IsDigitto check whether a character is a numeric digit. You can write:
If Char.IsDigit(e.KeyChar) Then ....
要检查特定键而不是字符，请使用KeyDown/KeyUp 事件的KeyCode属性获取Keys.NumPad0到 Keys.NumPad9之间的值。KeyPress 不提供此属性。
If (e.KeyCode >= Keys.NumPad0 and e.KeyCode <= Keys.NumPad9) Then ...如果要检查字符是否为数字，可以使用Char.IsDigit来检查字符是否为数字。你可以写：
If Char.IsDigit(e.KeyChar) Then ....
回答by Vivek S.
Keypad 0-9 is Keycode 96 to 105
键盘 0-9 是 Keycode 96 到 105
KEY CODE
------------------
numpad 0 96
numpad 1 97
numpad 2 98
numpad 3 99
numpad 4 100
numpad 5 101
numpad 6 102
numpad 7 103
numpad 8 104
numpad 9 105
