Differences

This shows you the differences between two versions of the page.

--- swdev:dotnet:enum [2011/03/09 10:36]
smayr created
+++ swdev:dotnet:enum [2011/12/02 14:11] (current)
smayr
@@ Line 13: / Line 13: @@
 To convert an enum value to string:
 <code csharp>
-public string GetEnumString(TMyColorobj)
+public string GetEnumString(TMyColor obj)
 {
      return Enum.GetName(typeof(TMyColor), obj);
@@ Line 21: / Line 21: @@
 To convert a string into an enum:
 <code csharp>
-string strcolor = Enum.Parse(typeof(string), "Red");
+TMyColor mycolor = (TMyColor)Enum.Parse(typeof(TMyColor), "Red");
+</code>
+== Enum with Description ==
+<code csharp>
+public enum TMyColor
+{
+  [Description("Red Color")]
+  Red,
+  [Description("Green Color")]
+  Green,
+  [Description("Blue Color")]
+  Blue
+}
+</code>
+To simply get the enum string equivalent (translate value into string):
+<code csharp>
+//----------------------------------------------------------------------------------------
+// Get enum string for the specified object.
+//----------------------------------------------------------------------------------------
+public static string GetEnumString(TMyColorobj)
+{
+  return Enum.GetName(typeof(TMyColor), obj);
+}
+</code>
+To query an enum value for its description:
+<code csharp>
+using System.ComponentModel;
+...
+//----------------------------------------------------------------------------------------
+// Get enum description string for the specified object.
+//----------------------------------------------------------------------------------------
+public static string GetEnumDescription(Enum value)
+{
+    System.Reflection.FieldInfo fi = value.GetType().GetField(value.ToString());
+    DescriptionAttribute[] attributes = (DescriptionAttribute[])fi.GetCustomAttributes(typeof(DescriptionAttribute), false);
+    if ((attributes != null) && (attributes.Length > 0))
+    {
+        return attributes[0].Description;
+    }
+    else
+    {
+        return value.ToString();
+    }
+}
+</code>
+== Enumerate Enum for creating ListBox ==
+<code csharp>
+///----------------------------------------------------------------------------------------
+/// <summary>
+/// Enumerate enums to easily create a drop down list based on an enum.
+/// Source: http://blog.spontaneouspublicity.com/post/2008/01/17/Associating-Strings-with-enums-in-C.aspx
+///
+/// Example:
+/// DropDownList stateDropDown = new DropDownList();
+/// foreach (States state in EnumToList<States>())
+/// {
+///    stateDropDown.Items.Add(GetEnumDescription(state));
+/// }
+/// </summary>
+/// <typeparam name="T"></typeparam>
+/// <returns></returns>
+///----------------------------------------------------------------------------------------
+public static IEnumerable<T> EnumToList<T>()
+{
+    Type enumType = typeof(T);
+    // Can't use generic type constraints on value types,
+    // so have to do check like this
+    if (enumType.BaseType != typeof(Enum))
+    {
+        throw new ArgumentException("T must be of type System.Enum");
+    }
+    Array enumValArray  = Enum.GetValues(enumType);
+    List<T> enumValList = new List<T>(enumValArray.Length);
+    foreach (int val in enumValArray)
+    {
+        enumValList.Add((T)Enum.Parse(enumType, val.ToString()));
+    }
+    return enumValList;
+}
 </code>