Class ArrayHandler<TElement>
Base class for all type handlers which handle PostgreSQL arrays.
Inheritance
Inherited Members
Namespace: Npgsql.TypeHandlers
Assembly: Npgsql.dll
Syntax
public class ArrayHandler<TElement> : ArrayHandler
Type Parameters
Name | Description |
---|---|
TElement |
Remarks
http://www.postgresql.org/docs/current/static/arrays.html.
The type handler API allows customizing Npgsql's behavior in powerful ways. However, although it is public, it should be considered somewhat unstable, and may change in breaking ways, including in non-major releases. Use it at your own risk.
Constructors
ArrayHandler(PostgresType, NpgsqlTypeHandler, Int32)
Declaration
public ArrayHandler(PostgresType arrayPostgresType, NpgsqlTypeHandler elementHandler, int lowerBound = 1)
Parameters
Type | Name | Description |
---|---|---|
PostgresType | arrayPostgresType | |
NpgsqlTypeHandler | elementHandler | |
System.Int32 | lowerBound |
Methods
Read<TRequestedArray>(NpgsqlReadBuffer, Int32, FieldDescription)
Reads a value of type TAny
with the given length from the provided buffer,
with the assumption that it is entirely present in the provided memory buffer and no I/O will be
required. This can save the overhead of async functions and improves performance.
Declaration
public override TRequestedArray Read<TRequestedArray>(NpgsqlReadBuffer buf, int len, FieldDescription fieldDescription = null)
Parameters
Type | Name | Description |
---|---|---|
NpgsqlReadBuffer | buf | The buffer from which to read. |
System.Int32 | len | The byte length of the value. The buffer might not contain the full length, requiring I/O to be performed. |
FieldDescription | fieldDescription | Additional PostgreSQL information about the type, such as the length in varchar(30). |
Returns
Type | Description |
---|---|
TRequestedArray | The fully-read value. |
Type Parameters
Name | Description |
---|---|
TRequestedArray |
Overrides
Read<TAny>(NpgsqlReadBuffer, Int32, Boolean, FieldDescription)
Reads a value of type TAny
with the given length from the provided buffer,
using either sync or async I/O.
Declaration
protected override ValueTask<TAny> Read<TAny>(NpgsqlReadBuffer buf, int len, bool async, FieldDescription fieldDescription = null)
Parameters
Type | Name | Description |
---|---|---|
NpgsqlReadBuffer | buf | The buffer from which to read. |
System.Int32 | len | The byte length of the value. The buffer might not contain the full length, requiring I/O to be performed. |
System.Boolean | async | If I/O is required to read the full length of the value, whether it should be performed synchronously or asynchronously. |
FieldDescription | fieldDescription | Additional PostgreSQL information about the type, such as the length in varchar(30). |
Returns
Type | Description |
---|---|
ValueTask<TAny> | The fully-read value. |
Type Parameters
Name | Description |
---|---|
TAny |
Overrides
ReadArray<TAnyElement>(NpgsqlReadBuffer, Boolean, Int32)
Reads an array of element type TAnyElement
from the given buffer buf
.
Declaration
protected ValueTask<Array> ReadArray<TAnyElement>(NpgsqlReadBuffer buf, bool async, int expectedDimensions = 0)
Parameters
Type | Name | Description |
---|---|---|
NpgsqlReadBuffer | buf | |
System.Boolean | async | |
System.Int32 | expectedDimensions |
Returns
Type | Description |
---|---|
ValueTask<System.Array> |
Type Parameters
Name | Description |
---|---|
TAnyElement |
ReadList<TAnyElement>(NpgsqlReadBuffer, Boolean)
Reads an array of element type TAnyElement
from the given buffer buf
.
Declaration
protected ValueTask<List<TAnyElement>> ReadList<TAnyElement>(NpgsqlReadBuffer buf, bool async)
Parameters
Type | Name | Description |
---|---|---|
NpgsqlReadBuffer | buf | |
System.Boolean | async |
Returns
Type | Description |
---|---|
ValueTask<System.Collections.Generic.List<TAnyElement>> |
Type Parameters
Name | Description |
---|---|
TAnyElement |
ValidateAndGetLength<TAny>(TAny, ref NpgsqlLengthCache, NpgsqlParameter)
Called to validate and get the length of a value of a generic NpgsqlParameter<T>.
Declaration
protected override int ValidateAndGetLength<TAny>(TAny value, ref NpgsqlLengthCache lengthCache, NpgsqlParameter parameter)
Parameters
Type | Name | Description |
---|---|---|
TAny | value | |
NpgsqlLengthCache | lengthCache | |
NpgsqlParameter | parameter |
Returns
Type | Description |
---|---|
System.Int32 |
Type Parameters
Name | Description |
---|---|
TAny |
Overrides
ValidateObjectAndGetLength(Object, ref NpgsqlLengthCache, NpgsqlParameter)
Responsible for validating that a value represents a value of the correct and which can be written for PostgreSQL - if the value cannot be written for any reason, an exception shold be thrown. Also returns the byte length needed to write the value.
Declaration
protected override int ValidateObjectAndGetLength(object value, ref NpgsqlLengthCache lengthCache, NpgsqlParameter parameter)
Parameters
Type | Name | Description |
---|---|---|
System.Object | value | The value to be written to PostgreSQL |
NpgsqlLengthCache | lengthCache | If the byte length calculation is costly (e.g. for UTF-8 strings), its result can be stored in the length cache to be reused in the writing process, preventing recalculation. |
NpgsqlParameter | parameter | The NpgsqlParameter instance where this value resides. Can be used to access additional information relevant to the write process (e.g. Size). |
Returns
Type | Description |
---|---|
System.Int32 | The number of bytes required to write the value. |
Overrides
WriteObjectWithLength(Object, NpgsqlWriteBuffer, NpgsqlLengthCache, NpgsqlParameter, Boolean)
Writes a value to the provided buffer, using either sync or async I/O.
Declaration
protected override Task WriteObjectWithLength(object value, NpgsqlWriteBuffer buf, NpgsqlLengthCache lengthCache, NpgsqlParameter parameter, bool async)
Parameters
Type | Name | Description |
---|---|---|
System.Object | value | The value to write. |
NpgsqlWriteBuffer | buf | The buffer to which to write. |
NpgsqlLengthCache | lengthCache | |
NpgsqlParameter | parameter | The NpgsqlParameter instance where this value resides. Can be used to access additional information relevant to the write process (e.g. Size). |
System.Boolean | async | If I/O is required to read the full length of the value, whether it should be performed synchronously or asynchronously. |
Returns
Type | Description |
---|---|
System.Threading.Tasks.Task |