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c# - How to check If a Enum contain a number?

I have a Enum like this:

 public enum PromotionTypes
{
    Unspecified = 0, 
    InternalEvent = 1,
    ExternalEvent = 2,
    GeneralMailing = 3,  
    VisitBased = 4,
    PlayerIntroduction = 5,
    Hospitality = 6
}

I want to check if this Enum contain a number I give. For example: When I give 4, Enum contain that, So I want to return True, If I give 7, There isn't 7 in this Enum, So it returns False. I tried Enum.IsDefine but it only check the String value. How can I do that?

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The IsDefined method requires two parameters. The first parameter is the type of the enumeration to be checked. This type is usually obtained using a typeof expression. The second parameter is defined as a basic object. It is used to specify either the integer value or a string containing the name of the constant to find. The return value is a Boolean that is true if the value exists and false if it does not.

enum Status
{
    OK = 0,
    Warning = 64,
    Error = 256
}

static void Main(string[] args)
{
    bool exists;

    // Testing for Integer Values
    exists = Enum.IsDefined(typeof(Status), 0);     // exists = true
    exists = Enum.IsDefined(typeof(Status), 1);     // exists = false

    // Testing for Constant Names
    exists = Enum.IsDefined(typeof(Status), "OK");      // exists = true
    exists = Enum.IsDefined(typeof(Status), "NotOK");   // exists = false
}

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