COM2Enum.cs source code in C# .NET

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                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / WinForms / Managed / System / WinForms / ComponentModel / COM2Interop / COM2Enum.cs / 1305376 / COM2Enum.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Windows.Forms.ComponentModel.Com2Interop { 
    using System.ComponentModel; 
    using System.Diagnostics;
    using System; 
    using System.Collections;
    using Microsoft.Win32;
    using System.Globalization;
 
    /// 
    ///  
    /// This class mimics a clr enum that we can create at runtime. 
    /// It associates an array of names with an array of values and converts
    /// between them. 
    ///
    /// A note here: we compare string values when looking for the value of an item.
    /// Typically these aren't large lists and the perf is worth it.  The reason stems
    /// from IPerPropertyBrowsing, which supplies a list of names and a list of 
    /// variants to mimic enum functionality.  If the actual property value is a DWORD,
    /// which translates to VT_UI4, and they specify their values as VT_I4 (which is a common 
    /// mistake), they won't compare properly and values can't be updated. 
    /// By comparing strings, we avoid this problem and add flexiblity to the system.
    ///  
    internal class Com2Enum {

        /// 
        ///  
        /// Our array of value string names
        ///  
        private string[] names; 

 
        /// 
        /// 
        /// Our values
        ///  
        private object[] values;
 
 

        ///  
        /// 
        /// Our cached array of value.ToString()'s
        /// 
        private string[] stringValues; 

        ///  
        ///  
        /// Should we allow values besides what's in the listbox?
        ///  
        private bool    allowUnknownValues;

        /// 
        ///  
        /// Our one and only ctor
        ///  
        public Com2Enum(string[] names, object[] values, bool allowUnknownValues) { 

            this.allowUnknownValues = allowUnknownValues; 

            // these have to be null and the same length
            if (names == null ||
                values == null || 
                names.Length != values.Length) {
                throw new ArgumentException(SR.GetString(SR.COM2NamesAndValuesNotEqual)); 
            } 

            PopulateArrays(names, values); 
        }

        /// 
        ///  
        /// Can this enum be values other than the strict enum?
        ///  
        public bool IsStrictEnum { 
            get {
                return !this.allowUnknownValues; 
            }
        }

        ///  
        /// 
        /// Retrieve a copy of the value array 
        ///  
        public virtual object[] Values {
            get { 
                return(object[])this.values.Clone();
            }
        }
 
        /// 
        ///  
        /// Retrieve a copy of the nme array. 
        /// 
        public virtual string[] Names { 
            get {
                return(string[])this.names.Clone();
            }
        } 

        ///  
        ///  
        /// Associate a string to the appropriate value.
        ///  
        public virtual object FromString(string s) {
            int bestMatch = -1;

            for (int i = 0; i < stringValues.Length; i++) { 
                if (String.Compare(names[i], s, true, CultureInfo.InvariantCulture) == 0 ||
                    String.Compare(stringValues[i], s, true, CultureInfo.InvariantCulture) == 0) { 
                    return values[i]; 
                }
 
                if (bestMatch == -1 && 0 == String.Compare(names[i], s, true, CultureInfo.InvariantCulture)) {
                    bestMatch = i;
                }
            } 

            if (bestMatch != -1) { 
                return values[bestMatch]; 
            }
 
            return allowUnknownValues ? s : null;
        }

        protected virtual void PopulateArrays(string[] names, object[] values) { 
            // setup our values...since we have to walk through
            // them anyway to do the ToString, we just copy them here. 
            this.names = new string[names.Length]; 
            this.stringValues = new string[names.Length];
            this.values = new object[names.Length]; 
            for (int i = 0; i < names.Length; i++) {
                //Debug.WriteLine(names[i] + ": item " + i.ToString() + ",type=" + values[i].GetType().Name + ", value=" + values[i].ToString());
                this.names[i] = names[i];
                this.values[i] = values[i]; 
                if (values[i] != null) {
                    this.stringValues[i] = values[i].ToString(); 
                } 
            }
        } 

        /// 
        /// 
        /// Retrieves the string name of a given value. 
        /// 
        public virtual string ToString(object v) { 
            if (v != null) { 

                // in case this is a real enum...try to convert it. 
                //
                if (values.Length > 0 && v.GetType() != values[0].GetType()) {
                    try {
                        v = Convert.ChangeType(v, values[0].GetType(), CultureInfo.InvariantCulture); 
                    }
                    catch{ 
                    } 
                }
 
                // we have to do this do compensate for small discrpencies
                // in a lot of objects in COM2 (DWORD -> VT_IU4, value we get is VT_I4, which
                // convert to Int32, UInt32 respectively
                string strVal = v.ToString(); 
                for (int i = 0; i < values.Length; i++) {
                    if (String.Compare(stringValues[i], strVal, true, CultureInfo.InvariantCulture) == 0) { 
                        return names[i]; 
                    }
                } 
                if (allowUnknownValues) {
                    return strVal;
                }
            } 
            return "";
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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COM2Enum.cs source code in C# .NET

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