C# Source Code: Check to see if an enum contains a valid value
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C# Source Code
Check to see if an enum contains a valid value
By:
Andrew Baker
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Date:
Thursday, November 04, 2004
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3302
Category:
General/Framework
Article:
The code below demonstrates how to manually iterate over all the value in an enum to check if an instance of an enum contains a valid value. Note, a second example at the bottom of this post shows you how to use the Enum.IsDefined function. /// <summary> /// Checks to see if a value is valid for the specified enum. This is necessary as DotNet will not /// throw an exception if you assign an invalid value. /// </summary> /// <param name="testValue">The potential value for this enum - should be of the type of the enumeration to test.</param> /// <returns>Returns true if the enum contains a valid value, else returns false</returns> /// <example> /// public enum MyEnumType : int /// { /// ValidValue = 1 /// } /// ... /// MyEnumType myValue = (MyEnumType)2; // Will not throw an error. /// if ( !EnumValid(myValue) ) /// { /// // Enum value has been detected as invalid. /// } /// </example> public static bool EnumValid(Enum testValue) { // Cast enum value to an int int testInt = Convert.ToInt32(testValue); // Get array of possible values System.Array values = Enum.GetValues(testValue.GetType()); for ( int index=0; index < values.Length; index++ ) { // Test if value matches if( testInt == (int)values.GetValue(index)) { //Found value return true; } } //Failed to find value return false; } /// <summary> /// Checks to see if a value is valid for the specified enum. This is necessary as DotNet will not /// throw an exception if you assign an invalid value. /// </summary> /// <param name="testValue">The potential value for this enum - should be of the type of the enumeration to test.</param> /// <returns>Returns true if the enum contains a valid value, else returns false</returns> /// <example> /// public enum MyEnumType : int /// { /// ValidValue = 1 /// } /// ... /// MyEnumType myValue = (MyEnumType)2; // Will not throw an error. /// if ( !EnumValid2(myValue) ) /// { /// // Enum value has been detected as invalid. /// } /// </example> public static bool EnumValid2(Enum testValue) { // Get the type and check its value is defined return Enum.IsDefined(testValue.GetType(), System.Convert.ToInt32(testValue) }
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