/// <summary>
/// Sets the imports of the specified composable part exactly once and they will not
/// ever be recomposed.
/// </summary>
/// <param name="part">
/// The <see cref="ComposablePart"/> to set the imports.
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="part"/> is <see langword="null"/>.
/// </exception>
/// <exception cref="CompositionException">
/// An error occurred during composition. <see cref="CompositionException.Errors"/> will
/// contain a collection of errors that occurred.
/// </exception>
/// <exception cref="ObjectDisposedException">
/// The <see cref="ICompositionService"/> has been disposed of.
/// </exception>
public void SatisfyImportsOnce(ComposablePart part)
{
ThrowIfDisposed();
if (_importEngine == null)
{
ImportEngine importEngine = new ImportEngine(this, _compositionOptions);
lock (_lock)
{
if (_importEngine == null)
{
Thread.MemoryBarrier();
_importEngine = importEngine;
importEngine = null;
}
}
if (importEngine != null)
{
importEngine.Dispose();
}
}
_importEngine.SatisfyImportsOnce(part);
}
public void SatisfyImportsOnce_Unsuccessful_ShouldNotBlockChanges()
{
var exportProvider = ExportProviderFactory.CreateRecomposable();
var engine = new ImportEngine(exportProvider);
var import = ImportDefinitionFactory.Create("Value");
var importer = PartFactory.CreateImporter(import);
ExceptionAssert.Throws<CompositionException>(() =>
engine.SatisfyImportsOnce(importer));
exportProvider.AddExport("Value", 22);
exportProvider.AddExport("Value", 23);
exportProvider.RemoveExport("Value");
GC.KeepAlive(importer);
}
public void SatisifyImportsOnce_Recomposable_ValueShouldNotChange_NoRecompositionRequested_ViaNonArgumentSignature()
{
var exportProvider = ExportProviderFactory.CreateRecomposable();
var engine = new ImportEngine(exportProvider);
exportProvider.AddExport("Value", 21);
var import = ImportDefinitionFactory.Create("Value", true);
var importer = PartFactory.CreateImporter(import);
engine.SatisfyImportsOnce(importer);
Assert.AreEqual(21, importer.GetImport(import));
exportProvider.ReplaceExportValue("Value", 42);
Assert.AreEqual(21, importer.GetImport(import), "Value should not change!");
GC.KeepAlive(importer);
}
