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
这个功能包括复制粘贴,拖放,按下键,防止溢出,非常简单
public partial class IntegerBox : TextBox
{
public IntegerBox()
{
InitializeComponent();
this.Text = 0.ToString();
}
protected override void OnPaint(PaintEventArgs pe)
{
base.OnPaint(pe);
}
private String originalValue = 0.ToString();
private void Integerbox_KeyPress(object sender, KeyPressEventArgs e)
{
originalValue = this.Text;
}
private void Integerbox_TextChanged(object sender, EventArgs e)
{
try
{
if(String.IsNullOrWhiteSpace(this.Text))
{
this.Text = 0.ToString();
}
this.Text = Convert.ToInt64(this.Text.Trim()).ToString();
}
catch (System.OverflowException)
{
MessageBox.Show("Value entered is to large max value: " + Int64.MaxValue.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
this.Text = originalValue;
}
catch (System.FormatException)
{
this.Text = originalValue;
}
catch (System.Exception ex)
{
this.Text = originalValue;
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK , MessageBoxIcon.Error);
}
}
}
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。
简单的回答是:
_textBox.TextChanged += delegate(System.Object o, System.EventArgs e)
{
TextBox _tbox = o as TextBox;
_tbox.Text = new string(_tbox.Text.Where(c => (char.IsDigit(c)) || (c == '.')).ToArray());
};
最简单粗暴的方法是使用组合框而不是带有只读的文本框。当然,只有当你希望用户使用一个合理的整数集,而不是试图接近无穷大时,它才有用。
使用正则表达式验证器:
<asp:TextBox ID="TextBoxNum" runat="server"></asp:TextBox><br />
<asp:RegularExpressionValidator ID="RegularExpressionValidator1"
ControlToValidate="TextBoxNum" runat="server"
ErrorMessage="Only numbers allowed"
ValidationExpression="\d+">
</asp:RegularExpressionValidator>
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;
}