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//------------------------------------------------------------------------------
// <copyright file="ReferenceConverter.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
/*
*/
namespace System.ComponentModel {
using Microsoft.Win32;
using System.Collections;
using System.ComponentModel.Design;
using System.Diagnostics;
using System.Globalization;
using System.Runtime.InteropServices;
using System.Runtime.Remoting;
using System.Runtime.Serialization.Formatters;
using System.Security.Permissions;
/// <devdoc>
/// <para>Provides a type converter to convert object references to and from various
/// other representations.</para>
/// </devdoc>
[HostProtection(SharedState = true)]
public class ReferenceConverter : TypeConverter {
private static readonly string none = SR.GetString(SR.toStringNone);
private Type type;
/// <devdoc>
/// <para>
/// Initializes a new instance of the <see cref='System.ComponentModel.ReferenceConverter'/> class.
/// </para>
/// </devdoc>
public ReferenceConverter(Type type) {
this.type = type;
}
/// <internalonly/>
/// <devdoc>
/// <para>Gets a value indicating whether this converter can convert an object in the
/// given source type to a reference object using the specified context.</para>
/// </devdoc>
public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) {
if (sourceType == typeof(string) && context != null) {
return true;
}
return base.CanConvertFrom(context, sourceType);
}
/// <internalonly/>
/// <devdoc>
/// <para>Converts the given object to the reference type.</para>
/// </devdoc>
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) {
if (value is string) {
string text = ((string)value).Trim();
if (!String.Equals(text, none) && context != null) {
// Try the reference service first.
//
IReferenceService refSvc = (IReferenceService)context.GetService(typeof(IReferenceService));
if (refSvc != null) {
object obj = refSvc.GetReference(text);
if (obj != null) {
return obj;
}
}
// Now try IContainer
//
IContainer cont = context.Container;
if (cont != null) {
object obj = cont.Components[text];
if (obj != null) {
return obj;
}
}
}
return null;
}
return base.ConvertFrom(context, culture, value);
}
/// <internalonly/>
/// <devdoc>
/// <para>Converts the given value object to the reference type
/// using the specified context and arguments.</para>
/// </devdoc>
public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) {
if (destinationType == null) {
throw new ArgumentNullException("destinationType");
}
if (destinationType == typeof(string)) {
if (value != null) {
// Try the reference service first.
//
if (context != null) {
IReferenceService refSvc = (IReferenceService)context.GetService(typeof(IReferenceService));
if (refSvc != null) {
string name = refSvc.GetName(value);
if (name != null) {
return name;
}
}
}
// Now see if this is an IComponent.
//
if (!Marshal.IsComObject(value) && value is IComponent) {
IComponent comp = (IComponent)value;
ISite site = comp.Site;
if (site != null) {
string name = site.Name;
if (name != null) {
return name;
}
}
}
// Couldn't find it.
return String.Empty;
}
return none;
}
return base.ConvertTo(context, culture, value, destinationType);
}
/// <internalonly/>
/// <devdoc>
/// <para>Gets a collection of standard values for the reference data type.</para>
/// </devdoc>
public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) {
object[] components = null;
if (context != null) {
ArrayList list = new ArrayList();
list.Add(null);
// Try the reference service first.
//
IReferenceService refSvc = (IReferenceService)context.GetService(typeof(IReferenceService));
if (refSvc != null) {
object[] objs = refSvc.GetReferences(type);
int count = objs.Length;
for (int i = 0; i < count; i++) {
if (IsValueAllowed(context, objs[i]))
list.Add(objs[i]);
}
}
else {
// Now try IContainer.
//
IContainer cont = context.Container;
if (cont != null) {
ComponentCollection objs = cont.Components;
foreach(IComponent obj in objs) {
if (obj != null && type.IsInstanceOfType(obj) &&
IsValueAllowed(context, obj)) {
list.Add(obj);
}
}
}
}
components = list.ToArray();
Array.Sort(components, 0, components.Length, new ReferenceComparer(this));
}
return new StandardValuesCollection(components);
}
/// <internalonly/>
/// <devdoc>
/// <para>Gets a value indicating whether the list of standard values returned from
/// <see cref='System.ComponentModel.ReferenceConverter.GetStandardValues'/> is an exclusive list. </para>
/// </devdoc>
public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) {
return true;
}
/// <internalonly/>
/// <devdoc>
/// <para>Gets a value indicating whether this object supports a standard set of values
/// that can be picked from a list.</para>
/// </devdoc>
public override bool GetStandardValuesSupported(ITypeDescriptorContext context) {
return true;
}
/// <devdoc>
/// <para>Gets a value indicating whether a particular value can be added to
/// the standard values collection.</para>
/// </devdoc>
protected virtual bool IsValueAllowed(ITypeDescriptorContext context, object value) {
return true;
}
/// <devdoc>
/// IComparer object used for sorting references
/// </devdoc>
private class ReferenceComparer : IComparer {
private ReferenceConverter converter;
public ReferenceComparer(ReferenceConverter converter) {
this.converter = converter;
}
public int Compare(object item1, object item2) {
String itemName1 = converter.ConvertToString(item1);
String itemName2 = converter.ConvertToString(item2);
return string.Compare(itemName1, itemName2, false, CultureInfo.InvariantCulture);
}
}
}
}
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