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

在文本框中简单地使用此代码:

private void textBox1_TextChanged(object sender, EventArgs e)
{

    double parsedValue;

    if (!double.TryParse(textBox1.Text, out parsedValue))
    {
        textBox1.Text = "";
    }
}

整数和浮点数都需要被接受，包括负数。

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    // Text
    string text = ((Control) sender).Text;

    // Is Negative Number?
    if (e.KeyChar == '-' && text.Length == 0)
    {
        e.Handled = false;
        return;
    }

    // Is Float Number?
    if (e.KeyChar == '.' && text.Length > 0 && !text.Contains("."))
    {
        e.Handled = false;
        return;
    }

    // Is Digit?
    e.Handled = (!char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar));
}

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;
    }

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;
}   

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>