SelectionRangeConverter.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / SelectionRangeConverter.cs / 1 / SelectionRangeConverter.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 */ 
namespace System.Windows.Forms {
    using System.Runtime.Serialization.Formatters; 
    using System.Runtime.Remoting;
    using System.Runtime.InteropServices;

    using Microsoft.Win32; 
    using System.Collections;
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization; 
    using System.Drawing;
    using System.Diagnostics; 
    using System.Globalization;
    using System.Reflection;

    ///  
    /// 
    ///      SelectionRangeConverter is a class that can be used to convert 
    ///      SelectionRange objects from one data type to another.  Access this 
    ///      class through the TypeDescriptor.
    ///  
    public class SelectionRangeConverter : TypeConverter {

        /// 
        ///  
        ///      Determines if this converter can convert an object in the given source
        ///      type to the native type of the converter. 
        ///  
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
            if (sourceType == typeof(string) || sourceType == typeof(DateTime)) { 
                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) || destinationType == typeof(DateTime)) {
                return true; 
            }
            return base.CanConvertTo(context, destinationType); 
        } 

        ///  
        /// 
        ///      Converts the given object to the converter's native type.
        /// 
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) { 
            if (value is string) {
                string text = ((string)value).Trim(); 
                if (text.Length == 0) { 
                    return new SelectionRange(DateTime.Now.Date, DateTime.Now.Date);
                } 

                // Separate the string into the two dates, and parse each one
                //
                if (culture == null) { 
                    culture = CultureInfo.CurrentCulture;
                } 
                char separator = culture.TextInfo.ListSeparator[0]; 
                string[] tokens = text.Split(new char[] {separator});
 
                if (tokens.Length == 2) {
                    TypeConverter dateTimeConverter = TypeDescriptor.GetConverter(typeof(DateTime));
                    DateTime start = (DateTime)dateTimeConverter.ConvertFromString(context, culture, tokens[0]);
                    DateTime end   = (DateTime)dateTimeConverter.ConvertFromString(context, culture, tokens[1]); 
                    return new SelectionRange(start, end);
                } 
                else { 
                    throw new ArgumentException(SR.GetString(SR.TextParseFailedFormat,
                                                              text, 
                                                              "Start" + separator + " End"));
                }
            }
            else if (value is DateTime) { 
                DateTime dt = (DateTime)value;
                return new SelectionRange(dt, dt); 
            } 

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


        ///  
        /// 
        ///      Converts the given object to another type.  The most common types to convert 
        ///      are to and from a string object.  The default implementation will make a call 
        ///      to ToString on the object if the object is valid and if the destination
        ///      type is string.  If this cannot convert to the desitnation type, this will 
        ///      throw a NotSupportedException.
        /// 
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
            if (destinationType == null) { 
                throw new ArgumentNullException("destinationType");
            } 
 
            SelectionRange range = value as SelectionRange;
            if (range != null) { 
                if (destinationType == typeof(string)) {
                    if (culture == null) {
                        culture = CultureInfo.CurrentCulture;
                    } 
                    string sep = culture.TextInfo.ListSeparator + " ";
                    PropertyDescriptorCollection props = GetProperties(value); 
                    string[] args = new string[props.Count]; 

                    for (int i = 0; i < props.Count; i++) { 
                        object propValue = props[i].GetValue(value);
                        args[i] = TypeDescriptor.GetConverter(propValue).ConvertToString(context, culture, propValue);
                    }
 
                    return string.Join(sep, args);
                } 
                if (destinationType == typeof(DateTime)) { 
                    return range.Start;
                } 
                if (destinationType == typeof(InstanceDescriptor)) {
                    ConstructorInfo ctor = typeof(SelectionRange).GetConstructor(new Type[] {
                        typeof(DateTime), typeof(DateTime)});
                    if (ctor != null) { 
                        return new InstanceDescriptor(ctor, new object[] {range.Start, range.End});
                    } 
                } 
            }
            return base.ConvertTo(context, culture, value, destinationType); 
        }

        /// 
        ///  
        ///      Creates an instance of this type given a set of property values
        ///      for the object.  This is useful for objects that are immutable, but still 
        ///      want to provide changable properties. 
        /// 
        public override object CreateInstance(ITypeDescriptorContext context, IDictionary propertyValues) { 
            try
            {
                return new SelectionRange((DateTime)propertyValues["Start"],
                                          (DateTime)propertyValues["End"]); 
            }
            catch (InvalidCastException invalidCast) 
            { 
                throw new ArgumentException(SR.GetString(SR.PropertyValueInvalidEntry), invalidCast);
            } 
            catch (NullReferenceException nullRef)
            {
                throw new ArgumentException(SR.GetString(SR.PropertyValueInvalidEntry), nullRef);
            } 
        }
 
        ///  
        /// 
        ///      Determines if changing a value on this object should require a call to 
        ///      CreateInstance to create a new value.
        /// 
        public override bool GetCreateInstanceSupported(ITypeDescriptorContext context) {
            return true; 
        }
 
        ///  
        /// 
        ///      Retrieves the set of properties for this type.  By default, a type has 
        ///      does not return any properties.  An easy implementation of this method
        ///      can just call TypeDescriptor.GetProperties for the correct data type.
        /// 
        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes) { 
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(SelectionRange), attributes);
            return props.Sort(new string[] {"Start", "End"}); 
        } 

        ///  
        /// 
        ///      Determines if this object supports properties.  By default, this
        ///      is false.
        ///  
        public override bool GetPropertiesSupported(ITypeDescriptorContext context) {
            return true; 
        } 
    }
} 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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SelectionRangeConverter.cs source code in C# .NET

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