float i=float.Parse(TextBox1.Text);
if(i不是浮点数)
{
Page.RegisterStartupScript("alert"," <script>alert('你输入的数不是数字,请重新输入'); </script>");
}
if(i不是浮点数)
{
Page.RegisterStartupScript("alert"," <script>alert('你输入的数不是数字,请重新输入'); </script>");
}
{
}
catch
{
}或者正则 ^(+-)?\d+(.\d+)?$
result=float.Parse(TextBox1.Text,out result);
if(!result)
{
Page.RegisterStartupScript("alert"," <script>alert('你输入的数不是数字,请重新输入'); </script>");
}
try
{
int i=int.Parse(TextBox.text)
}
catch
{
Page.RegisterStartupScript("alert"," <script>alert('你输入的数不是数字,请重新输入'); </script>"); }
result=float.TryParse(TextBox1.Text,out result);
if(!result)
{
Page.RegisterStartupScript("alert"," <script>alert('你输入的数不是数字,请重新输入'); </script>");
}
2。判断,一般是用正则表达式
private void txtpnum_KeyPress(object sender, KeyPressEventArgs e)
{
if ((e.KeyChar != 8 && !char.IsDigit(e.KeyChar)) && e.KeyChar != 13)
{
MessageBox.Show("请输入数字");
e.Handled = true;
}
}
public bool CheckIsNumber(string sSrc)
{
Regex regex = new Regex("^\\d+(\\.\\d+)?$");
if (regex.IsMatch(sSrc))
{
return true;
}
else
{
return false;
} }
double.TypeParse(string strValue,out double dOutValue);
呵呵
{
Regex r = new Regex(GetRegexString());
if (!r.Match(this.Text).Success)
{
return true;
}
return false;
}
private const string REGEX_STRING = @"^-?([1-9]{0,F}|[1-9]{0,F}\.|[1-9]{0,F}\.[0-9]{0,B}|[1-9]\d{0,F}|[1-9]\d{0,F}\.|
[1-9]\d{0,F}\.[0-9]{0,B}|0|0\.|0\.[0-9]{0,B})$"; protected override string GetRegexString()
{
return REGEX_STRING.Replace
("F", (this._forwardDotLength - 1).ToString()).Replace ("B",this._behindDotLength.ToString());
}
private bool IsNumeric(string number)
{
//TODO:判断是否是数字
try
{
number = number.Replace(".", ""); //去掉小数点 for (int i = 0; i < number.Length; i++) //判断是否为纯数字
{
if (!char.IsNumber(number, i))
{
return false;
}
}
return true;
}
catch
{
return false;
}
}