[英]Regex to allow only numbers between 100 and 999999
Can anyone help with C# code using regular expressions to validate a textbox which accepts only numbers between 100 and 999999 任何人都可以使用正则表达式帮助C#代码来验证仅接受100到999999之间的数字的文本框
Thanks, Lui. 谢谢,吕
You don't need a regex for this. 您不需要正则表达式。
int n;
if (!int.TryParse(textBox.Text.Trim(), out n) || n<100 || n>999999)
{
// Display error message: Out of range or not a number
}
EDIT: If the CF is targetted, then you can't use int.TryParse()
. 编辑:如果CF是目标,那么您不能使用int.TryParse()
。 Fallback on int.Parse()
instead and type a little more error-catching code: 改用int.Parse()
替代,然后输入更多错误捕获代码:
int n;
try
{
int n = int.Parse(textBox.Text.Trim());
if (n<100 || n>999999)
{
// Display error message: Out of range
}
else
{
// OK
}
}
catch(Exception ex)
{
// Display error message: Not a number.
// You may want to catch the individual exception types
// for more info about the error
}
Your requirement translates to three to six digits, first not zero. 您的要求转换为三到六位数字,第一位不为零。 I can't remember whether C# anchors REs by default, so I've put them in too. 我不记得默认情况下C#是否锚定RE,所以我也将它们放入了。
^[1-9][0-9]{2,5}$
A straightforward approach would be to use the regex 一种简单的方法是使用正则表达式
^[1-9][0-9]{2,5}$
If you want to allow leading zeroes (but still keep the 6-digit limit) the regex would be 如果要允许前导零(但仍保留6位数的限制),则正则表达式为
^(?=[0-9]{3,6}$)0*[1-9][0-9]{2,5}
This last one probably merits some explanation: it first uses positive lookahead [ (?=)
] to make sure that the whole input is 3 to 6 digits, and then it makes sure that it's made up of any number of leading zeroes followed by a number in the range 100-999999. 最后一个可能需要一些解释:首先使用正向先行[ (?=)
]确保整个输入为3到6位数字,然后确保它由任意数量的前导零组成,后跟一个范围在100-999999之间的数字。
However , it's possibly a good idea to use something more suited to the task (maybe a numeric comparison?). 但是 ,最好使用更适合该任务的内容(也许是一个数字比较?)。
Do you have to use regex? 您必须使用正则表达式吗? How about 怎么样
int result;
if(Int.TryParse(string, out result) && result > 100 && result < 999999) {
//do whatever with result
}
else
{
//invalid input
}
这将达到目的:
^[1-9]\d{2,5}$
您可以考虑的另一种方法
[1-9]\\d{2,5}
Why not use a NumericUpDown control instead which lets you specifiy a Minimum and Maximum value? 为什么不使用NumericUpDown控件代替它来指定最小值和最大值? And it will only allow numbers too, saving you additional validation to ensure anything non-numeric can be entered 而且它也将只允许数字,从而节省您额外的验证时间,以确保可以输入任何非数字的内容
From the example: 从示例:
public void InstantiateMyNumericUpDown()
{
// Create and initialize a NumericUpDown control.
numericUpDown1 = new NumericUpDown();
// Dock the control to the top of the form.
numericUpDown1.Dock = System.Windows.Forms.DockStyle.Top;
// Set the Minimum, Maximum, and initial Value.
numericUpDown1.Value = 100;
numericUpDown1.Maximum = 999999;
numericUpDown1.Minimum = 100;
// Add the NumericUpDown to the Form.
Controls.Add(numericUpDown1);
}
也许接受前导零:
^0*[1-9]\d{2,5}$
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