Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / ImageKeyConverter.cs / 1 / ImageKeyConverter.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; using System.Collections.Specialized; ////// /// ImageIndexConverter is a class that can be used to convert /// image index values one data type to another. /// public class ImageKeyConverter : StringConverter { 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; } } ////// /// 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 in the /// given source type to a string using the specified context. ////// /// public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) { if (value is string) { return (string)value; } if (value == null) { return ""; } return base.ConvertFrom(context, culture, value); } ///Converts the specified value object to a string object. ////// /// 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 && value is string && ((string)value).Length == 0) { return SR.GetString(SR.toStringNone); } else if (destinationType == typeof(string) && (value == null)) { 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] = ""; } else { values = new object[nImages]; } // Fill in the array // StringCollection imageKeys = imageList.Images.Keys; for (int i = 0; i < imageKeys.Count; i++) { if ((imageKeys[i] != null) && (imageKeys[i].Length != 0)) values[i] = imageKeys[i]; } return new StandardValuesCollection(values); } } } if (IncludeNoneAsStandardValue) { return new StandardValuesCollection(new object[] {""}); } 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 true; } ////// /// 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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