如何检查 C# 的三个枚举之一中是否存在值？

Question

I want to select the category of the string value checking in three enums.

CategoryEnum.cs

Category1 = 1,
Category2,
Category3

Category1.cs

Value1 = 1,
Value2 = 2

Category2.cs

Value3 = 1,
Value4 = 2

Category3.cs

Value5 = 1,
Value6 = 2

I have a string testValue and I want to check if it is present in Category1, Category2, or Category3 Enums and then return the string CategoryType in which the value is present. How to do this in C#?

Answer 1

If you add the values to a dictionary, you only have to use reflection once. Define

public enum CategoryEnum
{
    Category1 = 1,
    Category2,
    Category3
}

public enum Category1
{
    Value1 = 1,
    Value2 = 2
}

public enum Category2
{
    Value3 = 1,
    Value4 = 2
}

public enum Category3
{
    Value5 = 1,
    Value6 = 2
}

private static Dictionary<string, CategoryEnum> valueDict = new Dictionary<string, CategoryEnum>();

And

private string[] GetEnumValues<T>()
{
    T[] myEnumMembers = (T[])Enum.GetValues(typeof(T));
    return myEnumMembers.Select(e=>e.ToString()).ToArray();
}

Then you can initialize the dictionary like this:

foreach (var s in GetEnumValues<Category1>())
{
    valueDict.Add(s, CategoryEnum.Category1);
}
foreach (var s in GetEnumValues<Category2>())
{
    valueDict.Add(s, CategoryEnum.Category2);
}
foreach (var s in GetEnumValues<Category3>())
{
    valueDict.Add(s, CategoryEnum.Category3);
}

And look up a value like this:

var cat2Val3 = Category2.Value3;
Console.WriteLine(valueDict[cat2Val3.ToString()]);

Be sure not to overlap value names, though.

Answer 2

I fixed it by adding another value in the categoryenum "Unknown" And then used this code. Its a little tradeoff but simple.

private CategoryEnum GetColumnCategory(string value)
        {

            if (Enum.TryParse(value, out Category1 category1))
            {
                return CategoryEnum.Category1;
            }
            else if (Enum.TryParse(dataType, out Category2 category2))
            {
                return CategoryEnum.Category2;
            }
            else if (Enum.TryParse(dataType, out Category3 category3))
            {
                return CategoryEnum.Category3;
            }
            else
            {
                return CategoryEnum.Unknown;
            }

        }