public void SaveState(ShellViewModel shell, ShellView shellView, string fileName)
{
FileStream stream = null;
try
{
stream = new FileStream(fileName, FileMode.Create, FileAccess.Write);
using (var writer = new BinaryWriter(stream))
{
stream = null;
IEnumerable <LayoutItem> itemStates = shell.Items.Concat(shell.Widgets.Cast <LayoutItem>());
int itemCount = 0;
// reserve some space for items count, it'll be updated later
writer.Write(itemCount);
foreach (var item in itemStates)
{
if (!item.ShouldReopenOnStart)
{
continue;
}
var itemType = item.GetType();
List <ExportAttribute> exportAttributes = itemType
.GetCustomAttributes(typeof(ExportAttribute), false)
.Cast <ExportAttribute>().ToList();
var layoutType = typeof(LayoutItem);
// get exports with explicit types or names that inherit from ILayoutItem
var exportTypes = (from att in exportAttributes
// select the contract type if it is of type ILayoutitem. else null
let typeFromContract = att.ContractType != null &&
layoutType.IsAssignableFrom(att.ContractType)
? att.ContractType
: null
// select the contract name if it is of type ILayoutItem. else null
let typeFromQualifiedName = GetTypeFromContractNameAsILayoutItem(att)
// select the viewmodel tpye if it is of type ILayoutItem. else null
let typeFromViewModel = layoutType.IsAssignableFrom(itemType) ? itemType : null
// att.ContractType overrides att.ContractName if both are set.
// fall back to the ViewModel type of neither are defined.
let type = typeFromContract ?? typeFromQualifiedName ?? typeFromViewModel
where type != null
select type).ToList();
// throw exceptions here, instead of failing silently. These are design time errors.
var firstExport = exportTypes.FirstOrDefault();
if (firstExport == null)
{
throw new InvalidOperationException(string.Format(
"A ViewModel that participates in LayoutItem.ShouldReopenOnStart must be decorated with an ExportAttribute who's ContractType that inherits from ILayoutItem, infringing type is {0}.",
itemType));
}
if (exportTypes.Count > 1)
{
throw new InvalidOperationException(string.Format(
"A ViewModel that participates in LayoutItem.ShouldReopenOnStart can't be decorated with more than one ExportAttribute which inherits from ILayoutItem. infringing type is {0}.",
itemType));
}
var selectedTypeName = firstExport.AssemblyQualifiedName;
if (string.IsNullOrEmpty(selectedTypeName))
{
throw new InvalidOperationException(string.Format(
"Could not retrieve the assembly qualified type name for {0}, most likely because the type is generic.",
firstExport));
}
// TODO: it is possible to save generic types. It requires that every generic parameter is saved, along with its position in the generic tree... A lot of work.
writer.Write(selectedTypeName);
writer.Write(item.ContentId);
// Here's the tricky part. Because some items might fail to save their state, or they might be removed (a plug-in assembly deleted and etc.)
// we need to save the item's state size to be able to skip the data during deserialization.
// Save current stream position. We'll need it later.
long stateSizePosition = writer.BaseStream.Position;
// Reserve some space for item state size
writer.Write(0L);
long stateSize;
try
{
long stateStartPosition = writer.BaseStream.Position;
item.SaveState(writer);
stateSize = writer.BaseStream.Position - stateStartPosition;
}
catch
{
stateSize = 0;
}
// Go back to the position before item's state and write the actual value.
writer.BaseStream.Seek(stateSizePosition, SeekOrigin.Begin);
writer.Write(stateSize);
if (stateSize > 0)
{
// Got to the end of the stream
writer.BaseStream.Seek(0, SeekOrigin.End);
}
itemCount++;
}
writer.BaseStream.Seek(0, SeekOrigin.Begin);
writer.Write(itemCount);
writer.BaseStream.Seek(0, SeekOrigin.End);
shell.SaveLayout(writer.BaseStream);
}
}
catch
{
if (stream != null)
{
stream.Dispose();
}
}
}
public void LoadState(ShellViewModel shell, ShellView shellView, string fileName)
{
var layoutItems = new Dictionary <string, LayoutItem>();
if (!File.Exists(fileName))
{
return;
}
FileStream stream = null;
try
{
stream = new FileStream(fileName, FileMode.Open, FileAccess.Read);
using (var reader = new BinaryReader(stream))
{
stream = null;
int count = reader.ReadInt32();
for (int i = 0; i < count; i++)
{
string typeName = reader.ReadString();
string contentId = reader.ReadString();
long stateEndPosition = reader.ReadInt64();
stateEndPosition += reader.BaseStream.Position;
var contentType = Type.GetType(typeName);
bool skipStateData = true;
if (contentType != null)
{
var contentInstance = IoC.GetInstance(contentType, null) as LayoutItem;
if (contentInstance != null)
{
layoutItems.Add(contentId, contentInstance);
try
{
contentInstance.LoadState(reader);
skipStateData = false;
}
catch
{
skipStateData = true;
}
}
}
// Skip state data block if we couldn't read it.
if (skipStateData)
{
reader.BaseStream.Seek(stateEndPosition, SeekOrigin.Begin);
}
}
shell.LoadLayout(reader.BaseStream, shell.ShowTool, shell.OpenDocument, layoutItems);
}
}
catch
{
if (stream != null)
{
stream.Close();
}
}
}
