System.Windows.DeferrableContentConverter.RequireService C# (CSharp) Method

        private static T RequireService<T>(IServiceProvider provider) where T : class
        {
            T result = provider.GetService(typeof(T)) as T;
            if (result == null)
            {
                throw new InvalidOperationException(SR.Get(SRID.DeferringLoaderNoContext, typeof(DeferrableContentConverter).Name, typeof(T).Name));
            }
            return result;
        }
    }

        /// <summary>Converts the specified stream to a new <see cref="T:System.Windows.DeferrableContent" /> object.</summary>
        /// <param name="context">An <see cref="T:System.ComponentModel.ITypeDescriptorContext" /> that provides a format context. </param>
        /// <param name="culture">The <see cref="T:System.Globalization.CultureInfo" /> to use as the current culture. </param>
        /// <param name="value">The source stream to convert.</param>
        /// <returns>A new <see cref="T:System.Windows.DeferrableContent" /> object.</returns>
        /// <exception cref="T:System.ArgumentNullException">
        ///         <paramref name="context" /> is <see langword="null" />.</exception>
        /// <exception cref="T:System.InvalidOperationException">
        ///         <paramref name="context" /> is not able to provide the necessary XAML schema context for BAML.-or-
        ///         <see cref="T:System.Windows.Markup.IProvideValueTarget" /> service interpretation of <paramref name="context" /> determines that the target object is not a <see cref="T:System.Windows.ResourceDictionary" />.-or-
        ///         <paramref name="value" /> is not a valid byte stream.</exception>
        // Token: 0x060003AC RID: 940 RVA: 0x0000A73C File Offset: 0x0000893C
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value == null)
            {
                return(base.ConvertFrom(context, culture, value));
            }
            if (context == null)
            {
                throw new ArgumentNullException("context");
            }
            XamlSchemaContext     schemaContext         = DeferrableContentConverter.RequireService <IXamlSchemaContextProvider>(context).SchemaContext;
            Baml2006SchemaContext baml2006SchemaContext = schemaContext as Baml2006SchemaContext;

            if (baml2006SchemaContext == null)
            {
                throw new InvalidOperationException(SR.Get("ExpectedBamlSchemaContext"));
            }
            IXamlObjectWriterFactory objectWriterFactory = DeferrableContentConverter.RequireService <IXamlObjectWriterFactory>(context);
            IProvideValueTarget      provideValueTarget  = DeferrableContentConverter.RequireService <IProvideValueTarget>(context);
            IRootObjectProvider      rootObjectProvider  = DeferrableContentConverter.RequireService <IRootObjectProvider>(context);

            if (!(provideValueTarget.TargetObject is ResourceDictionary))
            {
                throw new InvalidOperationException(SR.Get("ExpectedResourceDictionaryTarget"));
            }
            Stream stream = value as Stream;

            if (stream == null)
            {
                byte[] array = value as byte[];
                if (array != null)
                {
                    stream = new MemoryStream(array);
                }
            }
            if (stream == null)
            {
                throw new InvalidOperationException(SR.Get("ExpectedBinaryContent"));
            }
            return(new DeferrableContent(stream, baml2006SchemaContext, objectWriterFactory, context, rootObjectProvider.RootObject));
        }