Serialization
The implementation demonstrated in this article can also be reviewed in the Serialize LocalDataSourceProvider SDK Example of the SDK Examples Browser
In this article we will show you how to serialize and deserialize LocalDataSourceProvider and all of its settings. You can use this feature to save the current state of the provider and load it next time the application is started.
Serialize LocalDataSourceProvider with DataContractSerializer
We've added the DataContract attribute to all classes used by LocalDataSourceProvider. So you can easily serialize it by using DataContractSerializer. Below you will find out how to create a serializer and use it with RadPivotGrid.
So lets create a simple class that we'll use to save (when serializing) and load (when deserializing) DataProviderSettings. You have to add the DataContract attribute to the new class and DataMember attribute for its properties.
[DataContract]
public class DataProviderSettings
{
[DataMember]
public object[] Aggregates { get; set; }
[DataMember]
public object[] Filters { get; set; }
[DataMember]
public object[] Rows { get; set; }
[DataMember]
public object[] Columns { get; set; }
[DataMember]
public int AggregatesLevel { get; set; }
[DataMember]
public PivotAxis AggregatesPosition { get; set; }
}The next step is to implement the serializer. When serializing the provider, you have to create an instance of DataProviderSettings class and set all of the properties. After that you can serialize the instance to a file or a stream. When using DataContractSerializer you have to give a collection of KnownTypes to the serializer. That's why we've created a new PivotSerializationHelper class which has a static member - KnownTypes. It consits of all types you'll need in order to serialize LocalDataSourceProvider. Here's an example how to implement your own serializer:
public abstract class DataProviderSerializer
{
public abstract IEnumerable<Type> KnownTypes { get; }
public string Serialize(object context)
{
string serialized = string.Empty;
IDataProvider dataProvider = context as IDataProvider;
if (dataProvider != null)
{
MemoryStream stream = new MemoryStream();
DataProviderSettings settings = new DataProviderSettings()
{
Aggregates = dataProvider.Settings.AggregateDescriptions.OfType<object>().ToArray(),
Filters = dataProvider.Settings.FilterDescriptions.OfType<object>().ToArray(),
Rows = dataProvider.Settings.RowGroupDescriptions.OfType<object>().ToArray(),
Columns = dataProvider.Settings.ColumnGroupDescriptions.OfType<object>().ToArray(),
AggregatesLevel = dataProvider.Settings.AggregatesLevel,
AggregatesPosition = dataProvider.Settings.AggregatesPosition
};
DataContractSerializer serializer = new DataContractSerializer(typeof(DataProviderSettings), KnownTypes);
serializer.WriteObject(stream, settings);
stream.Position = 0;
var streamReader = new StreamReader(stream);
serialized += streamReader.ReadToEnd();
}
return serialized;
}
public void Deserialize(object context, string savedValue)
{
IDataProvider dataProvider = context as IDataProvider;
if (dataProvider != null)
{
var stream = new MemoryStream();
var tw = new StreamWriter(stream);
tw.Write(savedValue);
tw.Flush();
stream.Position = 0;
DataContractSerializer serializer = new DataContractSerializer(typeof(DataProviderSettings), KnownTypes);
var result = serializer.ReadObject(stream);
dataProvider.Settings.AggregateDescriptions.Clear();
foreach (var aggregateDescription in (result as DataProviderSettings).Aggregates)
{
dataProvider.Settings.AggregateDescriptions.Add(aggregateDescription);
}
dataProvider.Settings.FilterDescriptions.Clear();
foreach (var filterDescription in (result as DataProviderSettings).Filters)
{
dataProvider.Settings.FilterDescriptions.Add(filterDescription);
}
dataProvider.Settings.RowGroupDescriptions.Clear();
foreach (var rowDescription in (result as DataProviderSettings).Rows)
{
dataProvider.Settings.RowGroupDescriptions.Add(rowDescription);
}
dataProvider.Settings.ColumnGroupDescriptions.Clear();
foreach (var columnDescription in (result as DataProviderSettings).Columns)
{
dataProvider.Settings.ColumnGroupDescriptions.Add(columnDescription);
}
dataProvider.Settings.AggregatesPosition = (result as DataProviderSettings).AggregatesPosition;
dataProvider.Settings.AggregatesLevel = (result as DataProviderSettings).AggregatesLevel;
}
}
}
public class LocalDataSourceSerializer : DataProviderSerializer
{
public override IEnumerable<Type> KnownTypes
{
get
{
return PivotSerializationHelper.KnownTypes;
}
}
}So the last step is to serialize the provider and deserialize it:
string lastSerializadProvider;
//serializiation
LocalDataSourceSerializer provider = new LocalDataSourceSerializer();
this.lastSerializadProvider = provider.Serialize(this.pivotGrid.DataProvider);
//deserialization
LocalDataSourceSerializer provider = new LocalDataSourceSerializer();
provider.Deserialize(this.pivotGrid.DataProvider, this.lastSerializadProvider);Serialize custom types
If you have implemented your own custom types, for example CustomGroupDescription, and you want to serialize your data, you have to do the following:
-
Set the DataContract attribute on each of your custom classes.
-
Set the DataMember attribute on each of the properties that you want to serialize.
-
Add all custom classes to the KnownTypes collection.
So if you have implemented a custom group description, it should be similar to this:
[DataContract]
public class CustomGroupDescription : PropertyGroupDescriptionBase
{
[DataMember]
public string MyCustomProperty { get; set; }
protected override void CloneOverride(Cloneable source)
{
this.MyCustomProperty = (source as CustomGroupDescription).MyCustomProperty;
}
protected override Cloneable CreateInstanceCore()
{
return new CustomGroupDescription();
}
}And here's the change in LocalDataSourceSerializer class:
public class LocalDataSourceSerializer : DataProviderSerializer
{
private IEnumerable<Type> myKnownTypes = PivotSerializationHelper.KnownTypes.Concat<Type>(new List<Type>() { typeof(CustomGroupDescription) });
public override IEnumerable<Type> KnownTypes
{
get
{
return myKnownTypes;
}
}
}