CursorConverter.cs source code in C# .NET

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

/* 
 */ 
namespace System.Windows.Forms {
 
    using System.Diagnostics;
    using Microsoft.Win32;
    using System.Collections;
    using System.ComponentModel; 
    using System.ComponentModel.Design.Serialization;
    using System.Globalization; 
    using System.Reflection; 
    using System.IO;
 
    /// 
    /// 
    ///      CursorConverter is a class that can be used to convert
    ///      colors from one data type to another.  Access this 
    ///      class through the TypeDescriptor.
    ///  
    public class CursorConverter : TypeConverter { 

        private StandardValuesCollection values; 

        /// 
        /// 
        ///      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(byte[])) {
                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(byte[])) {
                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(); 

                PropertyInfo[] props = GetProperties(); 
                for (int i = 0; i < props.Length; i++) {
                    PropertyInfo prop = props[i];
                    if (string.Equals(prop.Name, text, StringComparison.OrdinalIgnoreCase) ){
                        object[] tempIndex = null; 
                        return prop.GetValue(null, tempIndex);
                    } 
                } 
            }
 
            if (value is byte[]) {
                MemoryStream ms = new MemoryStream((byte[])value);
                return new Cursor(ms);
            } 

            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");
            }

            if (destinationType == typeof(string) && value != null) { 
                PropertyInfo[] props = GetProperties();
                int bestMatch = -1; 
 
                for (int i = 0; i < props.Length; i++) {
                    PropertyInfo prop = props[i]; 
                    object[] tempIndex = null;
                    Cursor c = (Cursor)prop.GetValue(null, tempIndex);
                    if (c == (Cursor)value) {
                        if (Object.ReferenceEquals(c, value)) { 
                            return prop.Name;
                        } 
                        else { 
                            bestMatch = i;
                        } 
                    }
                }

                if (bestMatch != -1) { 
                    return props[bestMatch].Name;
                } 
 
                // We throw here because we cannot meaningfully convert a custom
                // cursor into a string. In fact, the ResXResourceWriter will use 
                // this exception to indicate to itself that this object should
                // be serialized through ISeriazable instead of a string.
                //
                throw new FormatException(SR.GetString(SR.CursorCannotCovertToString)); 
            }
 
            if (destinationType == typeof(InstanceDescriptor) && value is Cursor) { 
                PropertyInfo[] props = GetProperties();
                foreach(PropertyInfo prop in props) { 
                    if (prop.GetValue(null, null) == value) {
                        return new InstanceDescriptor(prop, null);
                    }
                } 
            }
 
            if (destinationType == typeof(byte[])) { 
                if (value != null) {
                    MemoryStream ms = new MemoryStream(); 
                    Cursor cursor = (Cursor)value;
                    cursor.SavePicture(ms);
                    ms.Close();
                    return ms.ToArray(); 
                }
                else 
                    return new byte[0]; 
            }
 
            return base.ConvertTo(context, culture, value, destinationType);
        }

        ///  
        /// 
        ///      Retrieves the properties for the available cursors. 
        ///  
        private PropertyInfo[] GetProperties() {
            return typeof(Cursors).GetProperties(BindingFlags.Static | BindingFlags.Public); 
        }

        /// 
        ///  
        ///      Retrieves a collection containing a set of standard values
        ///      for the data type this validator is designed for.  This 
        ///      will return null if the data type does not support a 
        ///      standard set of values.
        ///  
        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) {
            if (values == null) {
                ArrayList list = new ArrayList();
                PropertyInfo[] props = GetProperties(); 
                for (int i = 0; i < props.Length; i++) {
                    PropertyInfo prop = props[i]; 
                    object[] tempIndex = null; 
                    Debug.Assert(prop.GetValue(null, tempIndex) != null, "Property " + prop.Name + " returned NULL");
                    list.Add(prop.GetValue(null, tempIndex)); 
                }

                values = new StandardValuesCollection(list.ToArray());
            } 

            return values; 
        } 

        ///  
        /// 
        ///      Determines if this object supports a standard set of values
        ///      that can be picked from a list.
        ///  
        public override bool GetStandardValuesSupported(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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CursorConverter.cs source code in C# .NET

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