CultureInfoConverter.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / CompMod / System / ComponentModel / CultureInfoConverter.cs / 2 / CultureInfoConverter.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 
namespace System.ComponentModel {
    using Microsoft.Win32; 
    using System.Collections;
    using System.ComponentModel.Design.Serialization;
    using System.Diagnostics;
    using System.Globalization; 
    using System.Reflection;
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.Remoting; 
    using System.Runtime.InteropServices;
    using System.Threading; 
    using System.Security.Permissions;

    /// 
    /// Provides a type converter to convert  
    /// objects to and from various other representations.
    ///  
    [HostProtection(SharedState = true)] 
    public class CultureInfoConverter : TypeConverter
    { 

        private StandardValuesCollection values;

        ///  
        ///      Retrieves the "default" name for our culture.
        ///  
        private string DefaultCultureString { 
            get {
                return SR.GetString(SR.CultureInfoConverterDefaultCultureString); 
            }
        }

        ///  
        ///    
        ///       Gets a value indicating whether this converter can 
        ///       convert an object in the given source type to a System.Globalization.CultureInfo 
        ///       object using
        ///       the specified context. 
        ///    
        /// 
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
            if (sourceType == typeof(string)) { 
                return true;
            } 
            return base.CanConvertFrom(context, sourceType); 
        }
 
        /// 
        ///    Gets a value indicating whether this converter can
        ///       convert an object to the given destination type using the context.
        ///  
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) {
            if (destinationType == typeof(InstanceDescriptor)) { 
                return true; 
            }
            return base.CanConvertTo(context, destinationType); 
        }

        /// 
        ///     
        ///       Converts the specified value object to a 
        ///       object. 
        ///     
        /// 
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) { 

            if (value is string) {
                string text = (string)value;
                CultureInfo retVal = null; 

                CultureInfo currentUICulture = Thread.CurrentThread.CurrentUICulture; 
 
                if (culture != null && culture.Equals(CultureInfo.InvariantCulture)) {
                    Thread.CurrentThread.CurrentUICulture = culture; 
                }

                try {
                    // Look for the default culture info. 
                    //
                    if (text == null || text.Length == 0 || string.Compare(text, DefaultCultureString, StringComparison.Ordinal) == 0) { 
                        retVal = CultureInfo.InvariantCulture; 
                    }
 
                    // Now look in our set of installed cultures.
                    //
                    if (retVal == null) {
                        ICollection values = GetStandardValues(context); 
                        IEnumerator e = values.GetEnumerator();
                        while (e.MoveNext()) { 
                            CultureInfo info = (CultureInfo)e.Current; 
                            if (info != null && string.Compare(info.DisplayName, text, StringComparison.Ordinal) == 0) {
                                retVal = info; 
                                break;
                            }
                        }
                    } 

                    // Now try to create a new culture info from this value 
                    // 
                    if (retVal == null) {
                        try { 
                            retVal = new CultureInfo(text);
                        }
                        catch {}
                    } 

                    // Finally, try to find a partial match 
                    // 
                    if (retVal == null) {
                        text = text.ToLower(CultureInfo.CurrentCulture); 
                        IEnumerator e = values.GetEnumerator();
                        while (e.MoveNext()) {
                            CultureInfo info = (CultureInfo)e.Current;
                            if (info != null && info.DisplayName.ToLower(CultureInfo.CurrentCulture).StartsWith(text)) { 
                                retVal = info;
                                break; 
                            } 
                        }
                    } 
                }

                finally {
                    Thread.CurrentThread.CurrentUICulture = currentUICulture; 
                }
 
                // No good.  We can't support it. 
                //
                if (retVal == null) { 
                    throw new ArgumentException(SR.GetString(SR.CultureInfoConverterInvalidCulture, (string)value));
                }
                return retVal;
            } 

            return base.ConvertFrom(context, culture, value); 
        } 

        ///  
        ///    
        ///       Converts the given
        ///       value object to the
        ///       specified destination type. 
        ///    
        ///  
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) { 
            if (destinationType == null) {
                throw new ArgumentNullException("destinationType"); 
            }

            if (destinationType == typeof(string)) {
 
                string retVal;
                CultureInfo currentUICulture = Thread.CurrentThread.CurrentUICulture; 
 
                if (culture != null && culture.Equals(CultureInfo.InvariantCulture)) {
                    Thread.CurrentThread.CurrentUICulture = culture; 
                }

                try {
                    if (value == null || value == CultureInfo.InvariantCulture) { 
                        retVal = DefaultCultureString;
                    } 
                    else { 
                        retVal = ((CultureInfo)value).DisplayName;
                    } 
                }
                finally {
                    Thread.CurrentThread.CurrentUICulture = currentUICulture;
                } 

                return retVal; 
            } 
            if (destinationType == typeof(InstanceDescriptor) && value is CultureInfo) {
                CultureInfo c = (CultureInfo) value; 
                ConstructorInfo ctor = typeof(CultureInfo).GetConstructor(new Type[] {typeof(string)});
                if (ctor != null) {
                    return new InstanceDescriptor(ctor, new object[] {c.Name});
                } 
            }
 
            return base.ConvertTo(context, culture, value, destinationType); 
        }
 
        /// 
        ///    
        ///       Gets a collection of standard values collection for a System.Globalization.CultureInfo
        ///       object using the specified context. 
        ///    
        ///  
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { 
           if (values == null) {
               CultureInfo[] installedCultures = CultureInfo.GetCultures(CultureTypes.SpecificCultures | CultureTypes.NeutralCultures); 

               // Add Culture.InvariantCulture for a default culture, then sort the array.
               CultureInfo[] array = new CultureInfo[installedCultures.Length + 1];
               Array.Copy(installedCultures, array, installedCultures.Length); 
               Array.Sort(array, new CultureComparer());
               Debug.Assert(array[0] == null); 
               if (array[0] == null) { 
                   //we replace null with the real default culture because there are code paths
                   // where the propgrid will send values from this returned array directly -- instead 
                   // of converting it to a string and then back to a value (which this relied on).
                   array[0] = CultureInfo.InvariantCulture; //null isn't the value here -- invariantculture is.
               }
 
               values = new StandardValuesCollection(array);
           } 
 
           return values;
        } 

        /// 
        ///    
        ///       Gets a value indicating whether the list of standard values returned from 
        ///       System.ComponentModel.CultureInfoConverter.GetStandardValues is an exclusive list.
        ///     
        ///  
        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) {
            return false; 
        }

        /// 
        ///     
        ///       Gets a value indicating whether this object supports a
        ///       standard set of values that can be picked from a list using the specified 
        ///       context. 
        ///    
        ///  
        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) {
            return true;
        }
 
        /// 
        ///      IComparer object used for sorting CultureInfos 
        ///      WARNING:  If you change where null is positioned, then you must fix CultureConverter.GetStandardValues! 
        /// 
        private class CultureComparer : IComparer { 

            public int Compare(object item1, object item2) {

                if (item1 == null) { 

                    // If both are null, then they are equal 
                    // 
                    if (item2 == null) {
                        return 0; 
                    }

                    // Otherwise, item1 is null, but item2 is valid (greater)
                    // 
                    return -1;
                } 
 
                if (item2 == null) {
 
                    // item2 is null, so item 1 is greater
                    //
                    return 1;
                } 

                String itemName1 = ((CultureInfo)item1).DisplayName; 
                String itemName2 = ((CultureInfo)item2).DisplayName; 

                CompareInfo compInfo = (CultureInfo.CurrentCulture).CompareInfo; 
                return compInfo.Compare(itemName1, itemName2, CompareOptions.StringSort);
            }
        }
    } 
}

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