129 lines
4.4 KiB
C#
129 lines
4.4 KiB
C#
//-----------------------------------------------------------------------
|
|
// <copyright file="StringColumnValue.cs" company="Microsoft Corporation">
|
|
// Copyright (c) Microsoft Corporation.
|
|
// </copyright>
|
|
//-----------------------------------------------------------------------
|
|
|
|
namespace Microsoft.Isam.Esent.Interop
|
|
{
|
|
using System;
|
|
using System.Diagnostics;
|
|
|
|
/// <summary>
|
|
/// A Unicode string column value.
|
|
/// </summary>
|
|
public class StringColumnValue : ColumnValue
|
|
{
|
|
/// <summary>
|
|
/// Internal value.
|
|
/// </summary>
|
|
private string internalValue;
|
|
|
|
/// <summary>
|
|
/// Gets the last set or retrieved value of the column. The
|
|
/// value is returned as a generic object.
|
|
/// </summary>
|
|
public override object ValueAsObject
|
|
{
|
|
[DebuggerStepThrough]
|
|
get { return this.Value; }
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets or sets the value of the column. Use <see cref="Api.SetColumns"/> to update a
|
|
/// record with the column value.
|
|
/// </summary>
|
|
public string Value
|
|
{
|
|
get
|
|
{
|
|
return this.internalValue;
|
|
}
|
|
|
|
set
|
|
{
|
|
this.internalValue = value;
|
|
this.Error = value == null ? JET_wrn.ColumnNull : JET_wrn.Success;
|
|
}
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the byte length of a column value, which is zero if column is null, otherwise
|
|
/// it matches the byte length of the string value. The byte length is determined in
|
|
/// assumption of two bytes per character.
|
|
/// </summary>
|
|
public override int Length
|
|
{
|
|
get { return this.Value != null ? this.Value.Length * sizeof(char) : 0; }
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the size of the value in the column. This returns 0 for
|
|
/// variable sized columns (i.e. binary and string).
|
|
/// </summary>
|
|
protected override int Size
|
|
{
|
|
[DebuggerStepThrough]
|
|
get { return 0; }
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets a string representation of this object.
|
|
/// </summary>
|
|
/// <returns>A string representation of this object.</returns>
|
|
public override string ToString()
|
|
{
|
|
return this.Value;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Recursive SetColumns method for data pinning. This populates the buffer and
|
|
/// calls the inherited SetColumns method.
|
|
/// </summary>
|
|
/// <param name="sesid">The session to use.</param>
|
|
/// <param name="tableid">
|
|
/// The table to set the columns in. An update should be prepared.
|
|
/// </param>
|
|
/// <param name="columnValues">
|
|
/// Column values to set.
|
|
/// </param>
|
|
/// <param name="nativeColumns">
|
|
/// Structures to put the pinned data in.
|
|
/// </param>
|
|
/// <param name="i">Offset of this object in the array.</param>
|
|
/// <returns>An error code.</returns>
|
|
internal override unsafe int SetColumns(JET_SESID sesid, JET_TABLEID tableid, ColumnValue[] columnValues, NATIVE_SETCOLUMN* nativeColumns, int i)
|
|
{
|
|
if (null != this.Value)
|
|
{
|
|
fixed (void* buffer = this.Value)
|
|
{
|
|
return this.SetColumns(
|
|
sesid, tableid, columnValues, nativeColumns, i, buffer, checked(this.Value.Length * sizeof(char)), true);
|
|
}
|
|
}
|
|
|
|
return this.SetColumns(sesid, tableid, columnValues, nativeColumns, i, null, 0, false);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Given data retrieved from ESENT, decode the data and set the value in the ColumnValue object.
|
|
/// </summary>
|
|
/// <param name="value">An array of bytes.</param>
|
|
/// <param name="startIndex">The starting position within the bytes.</param>
|
|
/// <param name="count">The number of bytes to decode.</param>
|
|
/// <param name="err">The error returned from ESENT.</param>
|
|
protected override void GetValueFromBytes(byte[] value, int startIndex, int count, int err)
|
|
{
|
|
if (JET_wrn.ColumnNull == (JET_wrn)err)
|
|
{
|
|
this.Value = null;
|
|
}
|
|
else
|
|
{
|
|
this.Value = StringCache.GetString(value, startIndex, count);
|
|
}
|
|
}
|
|
}
|
|
}
|