我有一个windows窗体应用程序与一个文本框控件,我想只接受整数值。在过去,我通过重载KeyPress事件并删除不符合规范的字符来进行这种验证。我已经看了MaskedTextBox控件,但我想一个更通用的解决方案,可以与也许正则表达式,或依赖于其他控件的值。
理想情况下,按下非数字字符要么不产生结果,要么立即向用户提供关于无效字符的反馈。
我有一个windows窗体应用程序与一个文本框控件,我想只接受整数值。在过去,我通过重载KeyPress事件并删除不符合规范的字符来进行这种验证。我已经看了MaskedTextBox控件,但我想一个更通用的解决方案,可以与也许正则表达式,或依赖于其他控件的值。
理想情况下,按下非数字字符要么不产生结果,要么立即向用户提供关于无效字符的反馈。
当前回答
这是我的方法:
using linq (easy to modify filter) copy/paste proof code keeps caret position when you press a forbidden character accepts left zeroes and any size numbers private void numeroCuenta_TextChanged(object sender, EventArgs e) { string org = numeroCuenta.Text; string formated = string.Concat(org.Where(c => (c >= '0' && c <= '9'))); if (formated != org) { int s = numeroCuenta.SelectionStart; if (s > 0 && formated.Length > s && org[s - 1] != formated[s - 1]) s--; numeroCuenta.Text = formated; numeroCuenta.SelectionStart = s; } }
其他回答
你可以使用TextChanged/ Keypress事件,使用正则表达式过滤数字,并采取一些行动。
这里有30多个答案,很多答案都是有用的。但我想分享system。windows。forms。textbox和system。windows。controls。textbox的通用形式。
在System.Windows.Controls.TextBox中没有可用的按键事件。 这个答案是为那些想用同样的逻辑实现System.Windows.Forms.TextBox和System.Windows.Controls.TextBox的人准备的。
这是NumberTextBox代码。对于System.Windows.Controls.TextBox,使用注释行代替之前的行。
public class NumberTextBox : System.Windows.Forms.TextBox
//public class NumberTextBox : System.Windows.Controls.TextBox
{
private double _maxValue;
private double _minValue;
private bool _flag;
private string _previousValue;
public NumberTextBox()
{
this.TextAlign = HorizontalAlignment.Right;
//TextAlignment = TextAlignment.Right;
KeyDown += TextBox_KeyDown;
TextChanged += TextBox_TextChanged;
_minValue = double.MinValue;
_maxValue = double.MaxValue;
}
private void TextBox_KeyDown(object sender, KeyEventArgs e)
{
_previousValue = this.Text;
_flag = this.SelectedText.Length > 0;
}
private void TextBox_TextChanged(object sender, EventArgs e)
//private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
var text = this.Text;
if (text.Length < 1) return;
var cursorPosition = SelectionStart == 0 ? SelectionStart : SelectionStart - 1;
var insertedChar = text[cursorPosition];
if (IsInvalidInput(insertedChar, cursorPosition, text))
{
HandleText(text, cursorPosition);
}
ValidateRange(text, cursorPosition);
}
private bool IsInvalidInput(char insertedChar, int cursorPosition, string text)
{
return !char.IsDigit(insertedChar) && insertedChar != '.' && insertedChar != '-' ||
insertedChar == '-' && cursorPosition != 0 ||
text.Count(x => x == '.') > 1 ||
text.Count(x => x == '-') > 1;
}
private void HandleText(string text, int cursorPosition)
{
this.Text = _flag ? _previousValue : text.Remove(cursorPosition, 1);
this.SelectionStart = cursorPosition;
this.SelectionLength = 0;
}
private void ValidateRange(string text, int cursorPosition)
{
try
{
if (text == "." || _minValue < 0 && text == "-") return;
var doubleValue = Convert.ToDouble(text);
if (doubleValue > _maxValue || doubleValue < _minValue)
{
HandleText(text, cursorPosition);
}
}
catch (Exception)
{
HandleText(text, cursorPosition);
}
}
protected void SetProperties(double minValue = double.MinValue, double maxValue = double.MaxValue)
{
_minValue = minValue;
_maxValue = maxValue;
}
}
PositiveNumberTextBox代码:
public class PositiveNumberTextBox : NumberTextBox
{
public PositiveNumberTextBox()
{
SetProperties(0);
}
}
FractionNumberTextBox代码:
public class FractionNumberTextBox : NumberTextBox
{
public FractionNumberTextBox()
{
SetProperties(0, 0.999999);
}
}
看一下WinForm中的输入处理
我已经发布了我的解决方案,在文本框上使用ProcessCmdKey和OnKeyPress事件。注释向您展示了如何使用Regex来验证键按和适当地阻止/允许。
不要忘记用户可以在文本框中粘贴无效文本。
如果你想限制它,遵循下面的代码:
private void ultraTextEditor1_TextChanged(object sender, EventArgs e)
{
string append="";
foreach (char c in ultraTextEditor1.Text)
{
if ((!Char.IsNumber(c)) && (c != Convert.ToChar(Keys.Back)))
{
}
else
{
append += c;
}
}
ultraTextEditor1.Text = append;
}
这可能有用。它允许“真实”数值,包括正确的小数点和前面的加号或减号。从相关的KeyPress事件中调用它。
private bool IsOKForDecimalTextBox(char theCharacter, TextBox theTextBox)
{
// Only allow control characters, digits, plus and minus signs.
// Only allow ONE plus sign.
// Only allow ONE minus sign.
// Only allow the plus or minus sign as the FIRST character.
// Only allow ONE decimal point.
// Do NOT allow decimal point or digits BEFORE any plus or minus sign.
if (
!char.IsControl(theCharacter)
&& !char.IsDigit(theCharacter)
&& (theCharacter != '.')
&& (theCharacter != '-')
&& (theCharacter != '+')
)
{
// Then it is NOT a character we want allowed in the text box.
return false;
}
// Only allow one decimal point.
if (theCharacter == '.'
&& theTextBox.Text.IndexOf('.') > -1)
{
// Then there is already a decimal point in the text box.
return false;
}
// Only allow one minus sign.
if (theCharacter == '-'
&& theTextBox.Text.IndexOf('-') > -1)
{
// Then there is already a minus sign in the text box.
return false;
}
// Only allow one plus sign.
if (theCharacter == '+'
&& theTextBox.Text.IndexOf('+') > -1)
{
// Then there is already a plus sign in the text box.
return false;
}
// Only allow one plus sign OR minus sign, but not both.
if (
(
(theCharacter == '-')
|| (theCharacter == '+')
)
&&
(
(theTextBox.Text.IndexOf('-') > -1)
||
(theTextBox.Text.IndexOf('+') > -1)
)
)
{
// Then the user is trying to enter a plus or minus sign and
// there is ALREADY a plus or minus sign in the text box.
return false;
}
// Only allow a minus or plus sign at the first character position.
if (
(
(theCharacter == '-')
|| (theCharacter == '+')
)
&& theTextBox.SelectionStart != 0
)
{
// Then the user is trying to enter a minus or plus sign at some position
// OTHER than the first character position in the text box.
return false;
}
// Only allow digits and decimal point AFTER any existing plus or minus sign
if (
(
// Is digit or decimal point
char.IsDigit(theCharacter)
||
(theCharacter == '.')
)
&&
(
// A plus or minus sign EXISTS
(theTextBox.Text.IndexOf('-') > -1)
||
(theTextBox.Text.IndexOf('+') > -1)
)
&&
// Attempting to put the character at the beginning of the field.
theTextBox.SelectionStart == 0
)
{
// Then the user is trying to enter a digit or decimal point in front of a minus or plus sign.
return false;
}
// Otherwise the character is perfectly fine for a decimal value and the character
// may indeed be placed at the current insertion position.
return true;
}