how to limit the values of a string with a certain name

Question

I want to have a string which is limited to 4-5 values (ex: "Insert", "update", "delete", "check") but no other values expect the above can be assigned to the string (similar to true and false in bool) but I want to know if it is possible without checking if the string is one of those values like so:

//not what i want
switch(str){
case "update":
isgoodvul=true;
break;
case "delete":
//(and so on).....
}

but more like

//what i want
string limited="hello world";
//error;
string limited="update";
//not error;
string any_other_string_name_exept_limited="hello world";
//not error;
string any_other_string_name_exept_limited="update";
//not error;

Have you considered using an Enum? You can parse strings to get the equivalent Enum value with relative ease. — JayV, Jun 26 '19 at 08:16
Sounds more like an [XY Problem](https://meta.stackexchange.com/questions/66377/what-is-the-xy-problem) to me. What you are trying to achieve? — SᴇM, Jun 26 '19 at 08:18
@avivgood1 Googe that maybe? But instead, I will recommend you to learn some basics of the language you are going to use. — SᴇM, Jun 26 '19 at 08:20
@SeM Im trying to build a func that create SQL statements for you — , Jun 26 '19 at 08:20
@avivgood1: why not use an existing ORM, such as Entity Framework? — Mark Cilia Vincenti, Jun 26 '19 at 08:21
@avivgood1 [enum (C# Reference)](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/enum) and https://www.google.co.uk/search?q=what+is+an+enum+c%23 — JayV, Jun 26 '19 at 08:21

score 0 · Answer 1 · answered Jun 26 '19 at 08:19

Create a HashSet to store your whitelist and check whether the input is in the whitelist or not, as below:

var whitelist = new HashSet<string>()
{
    "insert",
    "update",
    "delete",
    "check"
};

And then use as below:

bool isgoodvul = whitelist.Contains(str);

Elias N · Accepted Answer · 2019-06-26T08:41:23.917

0

You can use enums to get the behavior that you want. Define this:

enum MyAction
{
    insert = 0,
    update =1,
    delete = 2,
    check = 3
}

Then use it as such:

Enum action = MyAction.update;

switch(action){
  case(MyAction.insert)
    //Do insert
  case(MyAction.update)
    //Do update
...
}

edited Jun 26 '19 at 08:41

answered Jun 26 '19 at 08:25

Elias N

1,430
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19

how do I insert a new value to Enum action? – Jun 26 '19 at 08:30
1

@MarkCiliaVincenti But I agree with `switch` though. – SᴇM Jun 26 '19 at 08:38
@MarkCillaVincenti Flags should only be used when the numerical values of the enums are a power of 2 and the enumerable represents a collection of possible values, rather than a single value. Check [this](https://stackoverflow.com/questions/8447/what-does-the-flags-enum-attribute-mean-in-c) and [this](https://learn.microsoft.com/en-us/visualstudio/code-quality/ca2217-do-not-mark-enums-with-flagsattribute?view=vs-2019). In the link that you referenced, the efficiency is about using bitwise operations over hashsets – Elias N Jun 26 '19 at 08:38
@avivgood1, just add a `,whatever = 4` to the `enum MyAction`. And I suggest you use `switch` instead of `if... else if`. – Mark Cilia Vincenti Jun 26 '19 at 08:39

how to limit the values of a string with a certain name

2 Answers2