如何在文本框中只允许4位数 [英] How to allow only 4 digit in a textbox

问题描述

大家好



我在触摸屏环境中工作，我有一个屏幕，我有数字按钮0-9，我正在输入密码4位数。



我更改了该文本框的MaxLength属性。

当我使用键盘输入该文本框的值时，它工作正常意味着它不允许我输入超过4位数，但当我使用数字按钮进入时，它允许我输入更多然后4.



请告诉我是什么问题。





谢谢

解决方案

< blockquote>您可以尝试使用 MaskedTextBox Class [ ^ ]

可能更容易控制输入。

 <   asp：TextBox     ID   =  txtdigit    runat   =  server    MaxLength   =  4 >  < span class =code-keyword><   / asp：TextBox  >  
 <   asp：RegularExpressionValidator     ID   =  RegularExpressionValidator1    ControlToValidate   =  txtdigit    ValidationExpression   =  ^ [0-9] + 

runat = server ErrorMessage = 请仅输入数值。 > < / asp：RegularExpressionValidator >

Hi all

I am working in a touch screen environment where I am having one screen where i have number buttons 0-9 using which i am entering PIN number of 4 digit.

I changed the MaxLength property of that text box.
when i m entering the value to that text box using keyboard, it's working fine means it is not allowing me to enter more then 4 digits,but when i m entering using the number buttons, it is allowing me to enter more then 4.

Please tell me what is the problem.


Thank you

解决方案

You could try to use the MaskedTextBox Class[^]
It might make it easier to control the input.

<asp:TextBox ID="txtdigit" runat="server" MaxLength="4"></asp:TextBox>
    <asp:RegularExpressionValidator ID="RegularExpressionValidator1" ControlToValidate="txtdigit" ValidationExpression="^[0-9]+

" runat="server" ErrorMessage="Please enter only numeric value."></asp:RegularExpressionValidator>

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