The string linq query can be entered dynamically, not only by developer. And it should be validated.
Do you have a regex expression or nuget to check if a string is a valid linq expression?
For example for a valid string linq expression :

(a.AccountId== 33
|| a.AccountId == 2
|| a.AccountId == 15) &&
(a.RoleId == 1||  a.RoleId == 3||  a.RoleId == 4)

• Note - It can be also: (It can be each time a different linq query)

(a.TransactionId == 5 && a.EmployeeName == "Tony") || etc..

Example for string that can't be parsed:

(a.AccountId== 33
|| a.AccountId == 2
|| a.AccountId == 15)
(a.a.RoleId == 1||  a.RoleId == 3||  a.RoleId == 4)

Between those 2 , There is no Operator and you can see the a.a. which is invalid and can't be parsed to linq.

15)
(a.a.RoleId == 1||

If someone knows a good C# NuGet like ExpressionEvaluator for .net framework 4.5, Please let me know.
I have used ExpressionEvaluator, Dot net framework 4.5, But it says that this is a valid linq but it's not:

(a.AccountId== 33
|| a.AccountId == 2
|| a.AccountId == 15)
(a.a.RoleId == 1||  a.RoleId == 3||  a.RoleId == 4)

success is true, but it should be false.

success = new CompiledExpression(query);

• Result of a NuGet or Regex

Inside the textbox, Will return Valid:

"(a.ProfileId == 5 && a.ProfileName == 'Alex')"

Invalid: - l.l double l.l is invalid

"l.l.LinkId == 5 || l.LinkName == 'Alex'"

valid and string can be parsed

"l.LinkId == 5 || l.LinkName == 'Alex'"

The parameter l. or a. can be changed to any A-Z I have tried to use DynamicExpresso.Core but i need to specify the parameter.