限制文本框中的数字和字母 - C# [英] Restrict numbers and letters in textbox - C#

问题描述

我想限制可以在文本框中输入的数字和字母.假设我只想允许数字 0-5 和字母 a-d(小写和大写).我已经尝试过使用屏蔽文本框，但它只允许我指定数字、字母(均无限制)或数字和字母一起但按特定顺序指定.最好的情况是:用户尝试输入数字 6，但文本框中没有输入任何内容，对于 a-f 范围之外的字母也是如此.我认为最好使用的事件是 Keypress 事件，但我不知道如何实现限制.

I want to restrict what numbers and letters can be entered into a textbox. Let's say I only want to allow numbers 0-5 and letters a-d (both lower and uppercase). I already tried using a masked text box but it only let me specify numbers only, letters only (both without restriction) or numbers and letters together but in a particular order. Best scenario would be: user tries to enter number 6 and nothing gets entered into the textbox, same for letters outside the range a-f. I think the best event to use would be the Keypress event, but I am at a loss as to how I can achieve the restriction thing.

推荐答案

为您的文本框使用 KeyPress 事件.

Use the KeyPress Event for your textbox.

protected void myTextBox_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs)
{
    e.Handled = !IsValidCharacter(e.KeyChar);
}

private bool IsValidCharacter(char c)
{
    bool isValid = true;

    // put your logic here to define which characters are valid
    return isValid;
}

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