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
我喜欢简洁的代码
private void xmm_textbox_KeyPress(object sender, KeyPressEventArgs e) {
double x;
e.Handled = !double.TryParse(((TextBox)sender).Text, out x);
}
其他回答
尝试一个MaskedTextBox。它采用一种简单的掩码格式,这样你就可以将输入限制为数字或日期之类的。
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;
}
这正是设计已验证/正在验证事件的目的。
下面是MSDN上关于这个主题的文章:http://msdn.microsoft.com/en-us/library/system.windows.forms.control.validating.aspx
TL;DR版本:检查validate事件中的. text属性,并在数据无效时设置e.Cancel=True。
当你设置e.Cancel=True时,用户不能离开这个字段,但是你需要给他们一些错误的反馈。我将方框的背景颜色更改为浅红色,以表示有问题。确保将其设置回SystemColors。窗口时调用一个良好的值。
你可以在文本框的textchanged事件中这样做。
这是一个演示
private void textBox1_TextChanged(object sender, EventArgs e)
{
string actualdata = string.Empty;
char[] entereddata = textBox1.Text.ToCharArray();
foreach (char aChar in entereddata.AsEnumerable())
{
if (Char.IsDigit(aChar))
{
actualdata = actualdata + aChar;
// MessageBox.Show(aChar.ToString());
}
else
{
MessageBox.Show(aChar + " is not numeric");
actualdata.Replace(aChar, ' ');
actualdata.Trim();
}
}
textBox1.Text = actualdata;
}