ImageIndexConverter.cs source code in C# .NET

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

/* 
 */ 
namespace System.Windows.Forms {
 
    using Microsoft.Win32;
    using System.Collections;
    using System.ComponentModel;
    using System.Drawing; 
    using System.Diagnostics;
    using System.Globalization; 
    using System.Reflection; 

    ///  
    /// 
    ///      ImageIndexConverter is a class that can be used to convert
    ///      image index values one data type to another.
    ///  
    public class ImageIndexConverter : Int32Converter {
 
        private string parentImageListProperty  = "Parent"; 

        ///  
        protected virtual bool IncludeNoneAsStandardValue {
            get {
                return true;
            } 
        }
 
        ///  
        /// this is the property to look at when there is no ImageList property
        /// on the current object.  For example, in ToolBarButton - the ImageList is 
        /// on the ToolBarButton.Parent property.  In WinBarItem, the ImageList is on
        /// the WinBarItem.Owner property.
        /// 
        internal string ParentImageListProperty { 
            get {
                return parentImageListProperty; 
            } 
            set {
                parentImageListProperty = value; 
            }
        }

        ///  
        /// 
        ///     
        ///       Converts the given value object to a 32-bit signed integer object. 
        ///    
        ///  
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
            String stringValue = value as String;
            if (stringValue != null && String.Compare(stringValue, SR.GetString(SR.toStringNone), true, culture) == 0) {
                return -1; 
            }
 
            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 is int && ((int)value) == -1) { 
                return SR.GetString(SR.toStringNone); 
            }
 
            return base.ConvertTo(context, culture, value, destinationType);
        }

        ///  
        /// 
        ///      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 (context != null && context.Instance != null) {
                object instance = context.Instance; 

                PropertyDescriptor imageListProp = ImageListUtils.GetImageListProperty(context.PropertyDescriptor, ref instance); 
 
                while (instance != null && imageListProp == null) {
                    PropertyDescriptorCollection props = TypeDescriptor.GetProperties(instance); 

                    foreach (PropertyDescriptor prop in props) {
                        if (typeof(ImageList).IsAssignableFrom(prop.PropertyType)) {
                            imageListProp = prop; 
                            break;
                        } 
                    } 

                    if (imageListProp == null) { 

                        // We didn't find the image list in this component.  See if the
                        // component has a "parent" property.  If so, walk the tree...
                        // 
                        PropertyDescriptor parentProp = props[ParentImageListProperty];
                        if (parentProp != null) { 
                            instance = parentProp.GetValue(instance); 
                        }
                        else { 
                            // Stick a fork in us, we're done.
                            //
                            instance = null;
                        } 
                    }
                } 
 
                if (imageListProp != null) {
                    ImageList imageList = (ImageList)imageListProp.GetValue(instance); 

                    if (imageList != null) {

                        // Create array to contain standard values 
                        //
                        object[] values; 
                        int nImages = imageList.Images.Count; 
                        if (IncludeNoneAsStandardValue) {
                            values = new object[nImages + 1]; 
                            values[nImages] = -1;
                        }
                        else {
                            values = new object[nImages]; 
                        }
 
 
                        // Fill in the array
                        // 
                        for (int i = 0; i < nImages; i++) {
                            values[i] = i;
                        }
 
                        return new StandardValuesCollection(values);
                    } 
                } 
            }
 
            if (IncludeNoneAsStandardValue) {
                return new StandardValuesCollection(new object[] {-1});
            }
            else { 
                return new StandardValuesCollection(new object[0]);
            } 
        } 

        ///  
        /// 
        ///      Determines if the list of standard values returned from
        ///      GetStandardValues is an exclusive list.  If the list
        ///      is exclusive, then no other values are valid, such as 
        ///      in an enum data type.  If the list is not exclusive,
        ///      then there are other valid values besides the list of 
        ///      standard values GetStandardValues provides. 
        /// 
        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) { 
            return false;
        }

        ///  
        /// 
        ///      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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ImageIndexConverter.cs source code in C# .NET

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