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

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();
    }
}

两个选择:

Use a NumericUpDown instead. NumericUpDown does the filtering for you, which is nice. Of course it also gives your users the ability to hit the up and down arrows on the keyboard to increment and decrement the current value. Handle the appropriate keyboard events to prevent anything but numeric input. I've had success with this two event handlers on a standard TextBox: private void textBox1_KeyPress(object sender, KeyPressEventArgs e) { if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) && (e.KeyChar != '.')) { e.Handled = true; } // only allow one decimal point if ((e.KeyChar == '.') && ((sender as TextBox).Text.IndexOf('.') > -1)) { e.Handled = true; } }

您可以删除'的支票。如果你的文本框不允许小数点，'(和后续检查不止一个'.')。你也可以添加一个检查'-'如果你的文本框应该允许负值。

如果您想限制用户的位数，请使用:textBox1。MaxLength = 2;//这将允许用户只输入2位数字

在按钮点击，你可以检查文本框的文本循环:

char[] c = txtGetCustomerId.Text.ToCharArray();
bool IsDigi = true;

for (int i = 0; i < c.Length; i++)
     {
       if (c[i] < '0' || c[i] > '9')
      { IsDigi = false; }
     }
 if (IsDigi)
    { 
     // do something
    }

只是因为在一条线上做事情总是更有趣……

 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        e.Handled = !char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar);
    }

注意:这并不阻止用户复制/粘贴到此文本框。这并不是清除数据的安全方法。

我一直致力于一个组件的集合来完成WinForms中缺失的东西，这里是:高级表单

特别地，这是一个正则文本框类

/// <summary>Represents a Windows text box control that only allows input that matches a regular expression.</summary>
public class RegexTextBox : TextBox
{
    [NonSerialized]
    string lastText;

    /// <summary>A regular expression governing the input allowed in this text field.</summary>
    [Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
    [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
    public virtual Regex Regex { get; set; }

    /// <summary>A regular expression governing the input allowed in this text field.</summary>
    [DefaultValue(null)]
    [Category("Behavior")]
    [Description("Sets the regular expression governing the input allowed for this control.")]
    public virtual string RegexString {
        get {
            return Regex == null ? string.Empty : Regex.ToString();
        }
        set {
            if (string.IsNullOrEmpty(value))
                Regex = null;
            else
                Regex = new Regex(value);
        }
    }

    protected override void OnTextChanged(EventArgs e) {
        if (Regex != null && !Regex.IsMatch(Text)) {
            int pos = SelectionStart - Text.Length + (lastText ?? string.Empty).Length;
            Text = lastText;
            SelectionStart = Math.Max(0, pos);
        }

        lastText = Text;

        base.OnTextChanged(e);
    }
}

简单地添加像myNumbericTextBox这样的东西。RegexString = "^(\\d+|)$";应该足够了。