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Make input field validate a number range and a single character using regular expressions

This is a commonly asked question. But I am not getting the answer that I need. I had a look at MVC Validation make RegularExpression numeric only on string field (among many) for reference but I am not quite there yet.
I have an html5 input field bound to an MVC property. I want to make use of the [RegularExpression()] attribute but I am not getting the output that I need. I need my input to only take the following:
A single number between 0 and 7, or the % character
I tried the following:
[RegularExpression("^[0-7][%]")].
Where am I going wrong?

If you want to use range from 0 to 7. (Only single digit at a time) then use [0-7] and for % use [%]. To concatenate both the requirements(For or condition) use | in between two square brackets.
Your regular expression would be look like this
[RegularExpression("^[0-7]|[%]")]
^ at the starting of regular expressions, suggests that your string should starts with the number.
$ mentioned by #Stephen in comments states that your % must occurs at the end of string or expression.
Now its up to you, if you want string should be in D% format, where D is for digit and %, then use ^ in the beginning and $ at the end of regex. e.g. 5%
if this is not the case, then you can remove ^ and $ from the regex e.g %

Regular expression with only numbers, dots and minimum value

Im trying to make a regular expression that accept only numbers, dots and that has minimum value and max value.
E.g:
1.000 - valid
100.000 - valid
100.000a -not valid
.10 - not valid
100 - not valid
I have this, which works as i want with numbers and dots, only one thing is missing here, and that is minimum and maximum validation.
#"^([+-]?\d{1,3}(?:,\d{1,3})*(?:\.\d+)*)$"
PS:
Im using data annotations on .net core
Update
I have a javascript that separates users input in input field to thousand format like:
From: 1000000
To: 1.000.000
For better user experience.
But, the problem is the validation with data annotations.
With the RegularExpression i have above is working with the dots, i just need a minimum and maximum value.
I have tried with Range(min, max), but it recognise it as an invalid input because of the dots.
Regards

Given your comment I assume this is what your after:
^[+-]?[1-9]\d{0,2}(?:\.\d{3})+$
It matches a range of 1-3 digits (the first not being a 0), then followed by at least one (no upper limit) sequence of . + three digits.
This will match any number larger than one thousand with . as thousand separators. And since your attempt allowed it, this also allows an optional sign in the beginning.
See it in action here at regexstorm. Note! I can't get $ and multiline to work there so a \s is used instead to illustrate.

Considering that after every number there is space character in the string
This should do the job :
regex = #"[0-9]{1,3}\.[0-9]{1,5}"
Update :
As the obtained text will be numbers , so you could simply validate them for a range check .
For reference please have a look :regex reference
Let me know , if it doesn't works

Validating Positive number with comma and period

I need a regular expression validation expression that will
ALLOW
positive number(0-9)
, and .
DISALLOW
letter(a-z)
any other letter or symbol except . and ,
for example, on my asp.net text box, if I type anything#!#--, the regular expression validation will disallow it, if I type 10.000,50 or 10,000.50 it should allowed.
I've been trying to use this regex:
^\d+(\.\d\d)?$
but my textbox also must allow , symbol and I tried using only integer regex validation, it did disallow if I type string, but it also disallow . and , symbol while it should allow number(0-9) and also . and , symbol

Don't Use \d to match [0-9] in .NET
First off, in .NET, \d will match any digits in any script, such as:
654۳۲١८৮੪૯୫୬१७੩௮௫౫೮൬൪๘໒໕២៧៦᠖
So you really want to be using [0-9]
Incomplete Spec
You say you want to only allow "digits, commas and periods", but I don't think that's the whole spec. That would be ^[0-9,.]+$, and that would match
...,,,
See demo.
Tweaking the Spec
It's hard to guess what you really want to allow: would 10,1,1,1 be acceptable?
We could start with something like this, to get some fairly well-formed strings:
^(?:[0-9]+(?:[.,][0-9]+)?|[1-9][0-9]{0,2}(?:(?:\.[0-9]{3})*|(?:,[0-9]{3})*)(?:\.[0-9]+)?)$
Play with the demo, see what should and shouldn't match... When you are sure about the final spec, we can tweak the regex.
Sample Matches:
0
12
12.123
12,12
12,123,123
12,123,123.12456
12.125.457.22
Sample Non-Matches:
12,
123.
1,1,1,1

Your regex would be,
(?:\d|[,\.])+
OR
^(?:\d|[,\.])+$
It matches one or more numbers or , or . one or more times.
DEMO

Maybe you can use this one (starts with digit, ends with digit):
(\d+[\,\.])*\d+
If you need more sophisticated price Regex you should use:
(?:(?:[1-9]\d?\d?([ \,\.]?\d{3})*)|0)(?:[\.\,]\d+)?
Edit: To make it more reliable (and dont get 00.50) you can add starting and ending symbol check:
(^|\s)(?:(?:[1-9]\d?\d?([ \,\.]?\d{3})*)|0)(?:[\.\,]\d+)($|\s)?

I think the best regex for your condition will be :
^[\d]+(?:,\d+)*(?:\.\d+)?$
this will validate whatever you like
and at the same time:
not validate:
numbers ending in ,
numbers ending in .
numbers having . before comma
numbers having more than one decimal points
check out the demo here : http://regex101.com/r/zI0mJ4

Your format is a bit strange as it is not a standard format.
My first thought was to put a float instead of a string and put a Range validation attribute to avoid negative number.
But because of formatting, not sure it would work.
Another way is the regex, of course.
The one you propose means :
"some numbers then possibly a group formed by a dot and two numbers exactly".
This is not what you exepected.
Strictly fitted your example of a number lower than 100,000.99 one regex could be :
^[0-9]{1-2}[\.,][0-9]{3}([\.,][0-9]{1-2})?$
A more global regex, that accept all positive numbers is the one posted by Avinash Raj : (?:\d|[,\.])+

Should not allow single zero or 0.##

How do I restrict single zero in a numeric (Decimal may alow) textbox? Textbox can accept any number but it should not accept only zero or "0.##" as value.
For example: "900.55", "200.00" is valid but "0" and "0.105"is invalid.
I tried ^[1-9]\d\.?\d[0-9]* but it accepting the "0" and "0.##"

You're almost there.
^[1-9][0-9]*(\.[0-9]+)?$
The input must
start with a number 1-9
be followed by any sequence of 0-9
and optional:
a dot followed by one or more 0-9.
Notes:
This also disallows 3.. If you don't want that, replace the last + with a *.
You can use \d instead of [0-9]. I've used the latter to stay consistent with [1-9] and keep things simple.

I think you're close, but it may be easier to include the decimal and following digits in a group and make that entire group only allowable once like this one:
^[1-9][0-9]*(\.\d*)?
Also, here's a useful site for testing regular expressions.

I think it would be simpler to do this:
float result;
return float.TryParse(textBox1.Text, out result) && result < 1;

If the textbox only accepts valid numbers, and all you want to assert is that it is > 0. All you really need then is
^[1-9]
or if trailing prefix zero's are allowed
^0*[1-9]

You could alternatively write it using a negative lookahead:
^(?!0\b)\d+(\.\d*)?$
This has the added bonus of accepting numbers with a preceding 0 like 022.

I faced the same situation and solve this.
try out it.
#"[^0]*[0-9].\d{2}$

How to set a regular expression for amount

I have a textbox and in it a value like $8.00 I want to validate this textbox to always check for amount values and not accept letters or anything other than a value in the format of 0.00. How can I achieve this in a RegularExpressionValidator?
Thank you for the help.

The RegEx you are looking for is #"^\d+\.\d\d"
It matches strings with 1+ digits before point and exactly two digits after
If you want it to allow start a string from $, then use #"^\$\d+\.\d\d" or #"^\$?\d+\.\d\d" for optional $.
If you want $ to be separated from digits with spaces then use #"^\$?\s*\d+\.\d\d"

The following regular expressiong will allow numbers in the following format (12345.67, 0, 0.1)
^\d{1,5}(.\d{1,2})?$

I used one of the following before i hope it helps try it.
\d{1,3}(.)\d{1,2}
or
\d{1,3}.\d{2}