使用C#验证文本框 [英] validate a textbox using C#

问题描述

大家晚上好............
我只需要一个代码来验证文本框，该文本框不得超过200个字符.

谁能上前

Good evening to everyone............
I just need a code to validate a textbox that should not allow more than 200 characters.

Can anyone step forward

推荐答案

你好，

将其MaxLenght设置为200

Hello,

Set it''s MaxLenght to 200

处理TectChanged事件，然后执行以下操作:

Handle the TectChanged event, and do something like this:

TextBox ctrl = sender as TextBox;
if (ctrl.Length > 200)
{
    ctrl.Text = ctrl.Text.Substring(0,200);
}
labelCtrl.Text = string.Format("{0} of 200 characters", ctrl.Text.Length);

另一种解决方案是使用Control中的.Validating事件.然后，您可以使用ErrorProvider-Control向用户显示他在做什么错.

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating.aspx [ ^ ]

Another solution would be to use the .Validating event from the Control. You can than use a ErrorProvider-Control to show the user what he is doing wrong.

http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating.aspx[^]

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