[c#笔记]Winform TextBox中只能输入数字的几种常用方法(C#)

转载自:http://blog.csdn.net/hjingtao/article/details/7302448
修改了原文中一个正则错误

• Winform TextBox中只能输入数字的几种常用方法C
  • 方法一
  • 方法二
  • 方法三
  • 方法四
  • 方法五
  • 方法六
  • 方法七利用ASCII码处理办法

Winform TextBox中只能输入数字的几种常用方法(C#)

---

方法一

private void tBox_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == 0x20) e.KeyChar = (char)0;  //禁止空格键
    if ((e.KeyChar == 0x2D) && (((TextBox)sender).Text.Length == 0)) return;   //处理负数
    if (e.KeyChar > 0x20)
    {
        try
        {
            double.Parse(((TextBox)sender).Text + e.KeyChar.ToString());
        }
        catch
        {
            e.KeyChar = (char)0;   //处理非法字符
        }
    }
}

方法二：

private void TextBox_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar != 8 && !Char.IsDigit(e.KeyChar))
    {
        e.Handled = true;
    }
}

private void TextBox_KeyPress(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar != '\b' && !Char.IsDigit(e.KeyChar))
    {
        e.Handled = true;
    }

}

方法三:

private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
    if (e.KeyChar != '\b')//这是允许输入退格键
    {
        if ((e.KeyChar < '0') || (e.KeyChar > '9'))//这是允许输入0-9数字
        {
            e.Handled = true;
        }
    }
}

方法四:

private void textBox1_Validating(object sender, CancelEventArgs e)
{
    const string pattern = @"^\d+(\.\d)?$";

    string content = ((TextBox)sender).Text;

    if (!(Regex.IsMatch(content, pattern)))
    {
        errorProvider1.SetError((Control)sender, "只能输入数字!");
        e.Cancel = true;
    }
    else
        errorProvider1.SetError((Control)sender, null);
}

方法五:

private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)
{
    if (e.KeyChar == '.' && this.textBox1.Text.IndexOf(".") != -1)
    {
        e.Handled = true;
    }

    if (!((e.KeyChar >= 48 && e.KeyChar <= 57) || e.KeyChar == '.' || e.KeyChar == 8))
    {
        e.Handled = true;
    }

}

方法六：

private void tbx_LsRegCapital_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!Char.IsNumber(e.KeyChar) && !Char.IsPunctuation(e.KeyChar) && !Char.IsControl(e.KeyChar))
    {
        e.Handled = true;//消除不合适字符
    }
    else if (Char.IsPunctuation(e.KeyChar))
    {
        if (e.KeyChar != '.' || this.textBox1.Text.Length == 0)//小数点
        {
            e.Handled = true;
        }
        if (textBox1.Text.LastIndexOf('.') != -1)
        {
            e.Handled = true;
        }
    }
} 

方法七利用ASCII码处理办法:

// 48代表0，57代表9，8代表空格，46代表小数点
if ((e.KeyChar <= 48 ||
     e.KeyChar >= 57) &&
    (e.KeyChar != 8) &&
    (e.KeyChar != 46))
{
    e.Handled = true;
}