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
似乎目前对这个问题的许多答案都是手动解析输入文本。如果你正在寻找一个特定的内置数字类型(例如int或double),为什么不只是将工作委托给该类型的TryParse方法?例如:
public class IntTextBox : TextBox
{
string PreviousText = "";
int BackingResult;
public IntTextBox()
{
TextChanged += IntTextBox_TextChanged;
}
public bool HasResult { get; private set; }
public int Result
{
get
{
return HasResult ? BackingResult : default(int);
}
}
void IntTextBox_TextChanged(object sender, EventArgs e)
{
HasResult = int.TryParse(Text, out BackingResult);
if (HasResult || string.IsNullOrEmpty(Text))
{
// Commit
PreviousText = Text;
}
else
{
// Revert
var changeOffset = Text.Length - PreviousText.Length;
var previousSelectionStart =
Math.Max(0, SelectionStart - changeOffset);
Text = PreviousText;
SelectionStart = previousSelectionStart;
}
}
}
如果你想要更通用但仍然兼容Visual Studio的设计器:
public class ParsableTextBox : TextBox
{
TryParser BackingTryParse;
string PreviousText = "";
object BackingResult;
public ParsableTextBox()
: this(null)
{
}
public ParsableTextBox(TryParser tryParse)
{
TryParse = tryParse;
TextChanged += ParsableTextBox_TextChanged;
}
public delegate bool TryParser(string text, out object result);
public TryParser TryParse
{
set
{
Enabled = !(ReadOnly = value == null);
BackingTryParse = value;
}
}
public bool HasResult { get; private set; }
public object Result
{
get
{
return GetResult<object>();
}
}
public T GetResult<T>()
{
return HasResult ? (T)BackingResult : default(T);
}
void ParsableTextBox_TextChanged(object sender, EventArgs e)
{
if (BackingTryParse != null)
{
HasResult = BackingTryParse(Text, out BackingResult);
}
if (HasResult || string.IsNullOrEmpty(Text))
{
// Commit
PreviousText = Text;
}
else
{
// Revert
var changeOffset = Text.Length - PreviousText.Length;
var previousSelectionStart =
Math.Max(0, SelectionStart - changeOffset);
Text = PreviousText;
SelectionStart = previousSelectionStart;
}
}
}
最后,如果你想要完全通用的东西,不关心Designer支持:
public class ParsableTextBox<T> : TextBox
{
TryParser BackingTryParse;
string PreviousText;
T BackingResult;
public ParsableTextBox()
: this(null)
{
}
public ParsableTextBox(TryParser tryParse)
{
TryParse = tryParse;
TextChanged += ParsableTextBox_TextChanged;
}
public delegate bool TryParser(string text, out T result);
public TryParser TryParse
{
set
{
Enabled = !(ReadOnly = value == null);
BackingTryParse = value;
}
}
public bool HasResult { get; private set; }
public T Result
{
get
{
return HasResult ? BackingResult : default(T);
}
}
void ParsableTextBox_TextChanged(object sender, EventArgs e)
{
if (BackingTryParse != null)
{
HasResult = BackingTryParse(Text, out BackingResult);
}
if (HasResult || string.IsNullOrEmpty(Text))
{
// Commit
PreviousText = Text;
}
else
{
// Revert
var changeOffset = Text.Length - PreviousText.Length;
var previousSelectionStart =
Math.Max(0, SelectionStart - changeOffset);
Text = PreviousText;
SelectionStart = previousSelectionStart;
}
}
}
其他回答
通过这个简单的代码,您可以简单地防止添加非数值字符
if (long.TryParse(TextBox.Text,out long isparsable))
{
// your code to handle numbers
}
else
{
TextBox.Text="Only Numbers Allowed";
TextBox.Focus();
TextBox.SelectAll();
}
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;
}
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);
}
我已经为各种验证创建了一个可重用的文本框扩展类,并考虑共享它。
您所需要做的就是引发一个TextChange事件,然后调用Validate方法。它是这样的:
private void tbxAmount_TextChanged(object sender, EventArgs e)
{
tbxAmount.Validate(TextValidator.ValidationType.Amount);
}
下面是扩展类:
public static class TextValidator
{
public enum ValidationType
{
Amount,
Integer
}
/// <summary>
/// Validate a textbox on text change.
/// </summary>
/// <param name="tbx"></param>
/// <param name="validationType"></param>
public static void Validate(this TextBox tbx, ValidationType validationType)
{
PerformValidation(tbx, validationType);
tbx.Select(tbx.Text.Length, 0);
}
private static void PerformValidation(this TextBox tbx, ValidationType validationType)
{
char[] enteredString = tbx.Text.ToCharArray();
switch (validationType)
{
case ValidationType.Amount:
tbx.Text = AmountValidation(enteredString);
break;
case ValidationType.Integer:
tbx.Text = IntegerValidation(enteredString);
break;
default:
break;
}
tbx.SelectionStart = tbx.Text.Length;
}
private static string AmountValidation(char[] enteredString)
{
string actualString = string.Empty;
int count = 0;
foreach (char c in enteredString.AsEnumerable())
{
if (count >= 1 && c == '.')
{ actualString.Replace(c, ' '); actualString.Trim(); }
else
{
if (Char.IsDigit(c))
{
actualString = actualString + c;
}
if (c == '.')
{
actualString = actualString + c; count++;
}
else
{
actualString.Replace(c, ' ');
actualString.Trim();
}
}
}
return actualString;
}
private static string IntegerValidation(char[] enteredString)
{
string actualString = string.Empty;
foreach (char c in enteredString.AsEnumerable())
{
if (Char.IsDigit(c))
{
actualString = actualString + c;
}
else
{
actualString.Replace(c, ' ');
actualString.Trim();
}
}
return actualString;
}
}
你可以在这里找到完整的代码
Here is a simple solution that works for me.
public static bool numResult;
public static bool checkTextisNumber(string numberVal)
{
try
{
if (numberVal.Equals("."))
{
numResult = true;
}
else if (numberVal.Equals(""))
{
numResult = true;
}
else
{
decimal number3 = 0;
bool canConvert = decimal.TryParse(numberVal, out number3);
if (canConvert == true)
{
numResult = true;
}
else
numResult = false;
}
}
catch (System.Exception ex)
{
numResult = false;
}
return numResult;
}
string correctNum;
private void tBox_NumTester_TextChanged(object sender, TextChangedEventArgs e)
{
if(checkTextisNumber(tBox_NumTester.Text))
{
correctNum = tBox_NumTester.Text;
}
else
{
tBox_NumTester.Text = correctNum;
}
}