// Boolean flag used to determine when a character other than a number is entered.
private bool nonNumberEntered = false;
// Handle the KeyDown event to determine the type of character entered into the control.
private void textBox1_KeyDown(object sender, System.Windows.Forms.KeyEventArgs e)
{
// Initialize the flag to false.
nonNumberEntered = false;
// Determine whether the keystroke is a number from the top of the keyboard.
if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
{
// Determine whether the keystroke is a number from the keypad.
if (e.KeyCode < Keys.NumPad0 || e.KeyCode > Keys.NumPad9)
{
// Determine whether the keystroke is a backspace.
if(e.KeyCode != Keys.Back)
{
// A non-numerical keystroke was pressed.
// Set the flag to true and evaluate in KeyPress event.
nonNumberEntered = true;
}
}
}
//If shift key was pressed, it's not a number.
if (Control.ModifierKeys == Keys.Shift) {
nonNumberEntered = true;
}
}
// This event occurs after the KeyDown event and can be used to prevent
// characters from entering the control.
private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
// Check for the flag being set in the KeyDown event.
if (nonNumberEntered == true)
{
// Stop the character from being entered into the control since it is non-numerical.
e.Handled = true;
}
}
private void maskedTextBox1_KeyPress(object sender, KeyPressEventArgs e)
{
Char pressedKey = e.KeyChar;
if (Char.IsLetter(pressedKey) || Char.IsSeparator(pressedKey) || Char.IsPunctuation(pressedKey))
{
// Allow input.
e.Handled = false
}
else
// Stop the character from being entered into the control since not a letter, nor punctuation, nor a space.
e.Handled = true;
}
}
请注意,此代码段还允许您处理标点和分隔符键 .
0
此代码将区分字母字符键和非字母键:
private void maskedTextBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (Regex.IsMatch(e.KeyChar.ToString(), @"\p{L}"))
{
// this is a letter
}
else
{
// this is NOT a letter
}
}
// allow alphabetic characters, dots, commas, semicolon, colon
// and whitespace characters
if (Regex.IsMatch(e.KeyChar.ToString(), @"[\p{L}\.,;:\s]"))
3
// This is to allow only numbers.
// This Event Trigger, When key press event occures ,and it only allows the Number and Controls.,
private void txtEmpExp_KeyPress(object sender, KeyPressEventArgs e)
{
if(Char.IsControl(e.KeyChar)!=true&&Char.IsNumber(e.KeyChar)==false)
{
e.Handled = true;
}
}
//At key press event it will allows only the Characters and Controls.
private void txtEmpLocation_KeyPress(object sender, KeyPressEventArgs e)
{
if (Char.IsControl(e.KeyChar) != true && Char.IsNumber(e.KeyChar) == true)
{
e.Handled = true;
}
}
6
//添加文本框选择它并转到事件&在事件列表中双击“按键”事件 .
if (!char.IsLetter(e.KeyChar))
{
MessageBox.Show("Enter only characters");
}
}
7 回答
试试this代码
从MSDN(此代码显示如何处理KeyDown事件以检查输入的字符 . 在此示例中,它仅检查数字输入 . 您可以修改它以使其适用于字母输入而不是数字):
在每个可以想象的编程论坛上,这个问题可能已被提出并回答了一百万次 . 所提供的每个答案都具有与所述要求不同的区别 .
由于您使用的是
MaskedTextBox
,因此您可以使用其他验证功能,而不需要处理按键 . 您只需将Mask属性设置为"L"(需要字符)或"?"(可选字符) . 为了向用户显示输入不可接受的反馈,您可以使用BeepOnError
属性或添加工具提示以显示错误消息 . 应该在MaskedInputRejected
事件处理程序中实现此反馈机制 .MaskedTextBox
控件提供ValidatingType
属性来检查传递Mask的要求的输入,但可能不是正确的数据类型 . 在此类型验证后引发TypeValidationCompleted
事件,您可以处理它以确定结果 .如果您仍然需要处理按键事件,请继续阅读......!
在我的情况下,我建议的方法是,不是处理
KeyDown
事件(表面上你不需要高级键处理功能)或使用正则表达式匹配输入(坦率地说,矫枉过正),我只是使用内置的属性Char结构 .请注意,此代码段还允许您处理标点和分隔符键 .
此代码将区分字母字符键和非字母键:
更新:请注意,上述正则表达式模式将仅匹配字母字符,因此不允许使用空格,逗号,点等 . 为了允许更多种类的字符,您需要将它们添加到模式中:
//添加文本框选择它并转到事件&在事件列表中双击“按键”事件 .
这对我有用:)