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;
        }

    }

WPF的工作解决方案&一个简单的TextChangedEventArgs。

private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
{
    var TextBox = (sender as TextBox);

    // if not a numeric value, remove news characters
    if (Regex.IsMatch(TextBox.Text, "[^0-9]"))
    {
        foreach (TextChange Change in e.Changes)
        {
            TextBox.Text = TextBox.Text.Remove(Change.Offset, Change.AddedLength);

            TextBox.CaretIndex = Change.Offset;
        }
    }
}

我从上下文和您使用的标记假设您正在编写一个。net c#应用程序。在这种情况下，您可以订阅文本更改事件，并验证每个按键。

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "[^0-9]"))
    {
        MessageBox.Show("Please enter only numbers.");
        textBox1.Text = textBox1.Text.Remove(textBox1.Text.Length - 1);
    }
}

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

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);
        }
    }       
}

您可以使用TextChanged事件

private void textBox_BiggerThan_TextChanged(object sender, EventArgs e)
{
    long a;
    if (! long.TryParse(textBox_BiggerThan.Text, out a))
    {
        // If not int clear textbox text or Undo() last operation
        textBox_LessThan.Clear();
    }
}