C# 4 and .NET 4

User-Defined Types ❘ 959
}
}
// Put your code here
return m_Null;
}
public static SqlCoordinate Null
{
get
{
SqlCoordinate h = new SqlCoordinate();
h.m_Null = true;
return h;
}
}
public static SqlCoordinate Parse(SqlString s)
{
if (s.IsNull)
return Null;
SqlCoordinate u = new SqlCoordinate();
// Put your code here
return u;
}
// This is a place-holder method
public string Method1()
{
//Insert method code here
return "Hello";
}
// This is a place-holder static method
public static SqlString Method2()
{
// Insert method code here
return new SqlString("Hello");
}
// This is a placeholder field member
public int var1;
// Private member
private bool m_Null;
Because this type can also be used directly from client code, it is a good idea to add a namespace, which is
not done automatically.
The struct SqlCoordinate implements the interface INullable. The interface INullable is required for
UDTs because database types can also be null. The attribute SqlUserDefinedType is used for automatic
deployment with Visual Studio for UDTs. The argument Format.Native defines the serialization format
to be used. Two serialization formats are possible: Format.Native and Format.UserDefined. Format
.Native is the simple serialization format where the engine performs serialization and deserialization of
instances. This serialization allows only value types (predefined and structs of value types). Reference types
(which include the string type) require the UserDefined serialization format. With the SqlCoordinate
struct, the data types to serialize are of type int and bool, which are value types.
Using Format.UserDefined requires the interface IBinarySerialize to be implemented. The
IBinarySerialize interface provides custom implementation for user-defined types. Read() and Write()
methods must be implemented for serialization of the data to a BinaryReader and a BinaryWriter.
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