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
我也在寻找最好的方法来检查文本框中只有数字和键盘的问题是,它不支持通过右键单击或剪贴板复制粘贴,所以提出了这个代码,验证光标离开文本字段时,它也检查空字段。(newguy改编版)
private void txtFirstValue_MouseLeave(object sender, EventArgs e)
{
int num;
bool isNum = int.TryParse(txtFirstValue.Text.Trim(), out num);
if (!isNum && txtFirstValue.Text != String.Empty)
{
MessageBox.Show("The First Value You Entered Is Not a Number, Please Try Again", "Invalid Value Detected", MessageBoxButtons.OK, MessageBoxIcon.Error);
txtFirstValue.Clear();
}
}
其他回答
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; } }
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;
}
}
}
3解决方案
1)
//Add to the textbox's KeyPress event
//using Regex for number only textBox
private void txtBox_KeyPress(object sender, KeyPressEventArgs e)
{
if (!System.Text.RegularExpressions.Regex.IsMatch(e.KeyChar.ToString(), "\\d+"))
e.Handled = true;
}
2) 来自MSDN的另一个解决方案
// 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, 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;
}
}
}
}
private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
if (nonNumberEntered == true)
{
MessageBox.Show("Please enter number only...");
e.Handled = true;
}
}
源http://msdn.microsoft.com/en-us/library/system.windows.forms.control.keypress (v =应用程序). aspx
3)使用MaskedTextBox: http://msdn.microsoft.com/en-us/library/system.windows.forms.maskedtextbox.aspx
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。
很抱歉吵醒死人,但我想有人可能会觉得这对将来的参考有用。
以下是我的处理方法。它处理浮点数,但可以很容易地修改为整数。
基本上你只能按0 - 9和。
前面只能有一个0。
所有其他字符将被忽略,光标位置保持不变。
private bool _myTextBoxChanging = false;
private void myTextBox_TextChanged(object sender, EventArgs e)
{
validateText(myTextBox);
}
private void validateText(TextBox box)
{
// stop multiple changes;
if (_myTextBoxChanging)
return;
_myTextBoxChanging = true;
string text = box.Text;
if (text == "")
return;
string validText = "";
bool hasPeriod = false;
int pos = box.SelectionStart;
for (int i = 0; i < text.Length; i++ )
{
bool badChar = false;
char s = text[i];
if (s == '.')
{
if (hasPeriod)
badChar = true;
else
hasPeriod = true;
}
else if (s < '0' || s > '9')
badChar = true;
if (!badChar)
validText += s;
else
{
if (i <= pos)
pos--;
}
}
// trim starting 00s
while (validText.Length >= 2 && validText[0] == '0')
{
if (validText[1] != '.')
{
validText = validText.Substring(1);
if (pos < 2)
pos--;
}
else
break;
}
if (pos > validText.Length)
pos = validText.Length;
box.Text = validText;
box.SelectionStart = pos;
_myTextBoxChanging = false;
}
下面是一个快速修改的int版本:
private void validateText(TextBox box)
{
// stop multiple changes;
if (_myTextBoxChanging)
return;
_myTextBoxChanging = true;
string text = box.Text;
if (text == "")
return;
string validText = "";
int pos = box.SelectionStart;
for (int i = 0; i < text.Length; i++ )
{
char s = text[i];
if (s < '0' || s > '9')
{
if (i <= pos)
pos--;
}
else
validText += s;
}
// trim starting 00s
while (validText.Length >= 2 && validText.StartsWith("00"))
{
validText = validText.Substring(1);
if (pos < 2)
pos--;
}
if (pos > validText.Length)
pos = validText.Length;
box.Text = validText;
box.SelectionStart = pos;
_myTextBoxChanging = false;
}