Check the value of a class member of type string that can only assume a few values

Question

I have the following partial class created by running xsd /c against an XML schema file:

[System.CodeDom.Compiler.GeneratedCodeAttribute("xsd", "4.0.30319.33440")]
[System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(Namespace="example.com")]
public partial class FRUITQueryType {

    private string fruitTypeField;

    /// <remarks/>
    [System.Xml.Serialization.XmlAttributeAttribute()]
    public string FruitType {
        get {
            return this.fruitTypeField;
        }
        set {
            this.fruitTypeField = value;
        }
    }
}

Although the type is string, I know there are only three possible values for that field, say Banana, Orange, and Blueberry.

In another part of the program, I check the content of that field:

// assume fruit is an instance of FRUITQueryType
if (fruit.FruitType == "Banana")
{
    // do something
}

However, since there are only a few possible values for the field, this approach does not feel neat. I think it would be better if I could check the value of the field somewhat along these lines:

if (fruit.FruitType == FRUITQueryType.FruitType.Banana) // or something similar

Is there any point in achieving this? If so, what's the best way to do it? By creating a class/struct with three static members containing Banana, Orange and Blueberry?

Yiou probably want to take a look at [C# enum](http://msdn.microsoft.com/en-us/library/sbbt4032.aspx) — Adriaan Stander, Oct 05 '14 at 13:16
Not much you can do if you're stuck with lame xsd. Check [this post](http://stackoverflow.com/questions/1168532/xsd-definition-for-enumerated-value) for general advice. — Hans Passant, Oct 05 '14 at 13:17
@astander I thought about `enum`s, but then how can I check that the content of `FruitType` (a string) is equal to `FruitEnum.Banana`? — Jir, Oct 05 '14 at 22:10
@HansPassant that'd be the way to go. Unfortunately I can't modify the original xsd. — Jir, Oct 05 '14 at 22:11
@HansPassant your initial diagnosis was spot on: "lame xsd syndrome" :D — Jir, Oct 06 '14 at 07:55

score 0 · Accepted Answer · answered Oct 05 '14 at 22:18

I came up with a temporary solution - not ideal but does the job.

I defined the three strings as constants in the extended class:

public partial class FRUITQueryType
{
    public const string Banana = "Banana";
    public const string Orange = "Orange";
    public const string Blueberry = "Blueberry";
    // ...
}

This way the check becomes:

if (fruit.FruitType == FRUITQueryType.Banana)

I must say I am not entirely happy with this solution, as it feels like cluttering the class. However, if I defined the constants in a sub-class/struct (say, public struct FruitChoice), then the check would become more awkward, too (if (fruit.FruitType == FRUITQueryType.FruitChoice.Banana))

Anyone comes up with a neater way?

Check the value of a class member of type string that can only assume a few values

1 Answers1