/// <summary>
/// Reads the value of a cell from the file wrapper, checks to see if it null using
/// <paramref name="isNullFunc"/>, and converts it to the proper output type using
/// <paramref name="convertFunc"/>.
/// </summary>
/// <param name="offset">Offset into the file to read from</param>
/// <param name="rowId">Internal ID of the row to set on all cells in this row</param>
/// <param name="convertFunc">Function to use to convert the buffer to the target type</param>
/// <param name="isNullFunc">
/// If provided, this function will be used to determine if the value is null
/// </param>
/// <param name="toStringFunc">Optional function to use to convert the object to a string.</param>
/// <typeparam name="T">The expected type of the cell. Used to keep the code honest</typeparam>
/// <returns>The object, a display value, and the length of the value + its length</returns>
private FileStreamReadResult ReadCellHelper <T>(long offset, long rowId,
Func <int, T> convertFunc,
Func <int, bool> isNullFunc = null,
Func <T, string> toStringFunc = null)
{
LengthResult length = ReadLength(offset);
DbCellValue result = new DbCellValue {
RowId = rowId
};
if (isNullFunc == null ? length.ValueLength == 0 : isNullFunc(length.TotalLength))
{
result.RawObject = null;
result.DisplayValue = SR.QueryServiceCellNull;
result.IsNull = true;
}
else
{
AssureBufferLength(length.ValueLength);
fileStream.Read(buffer, 0, length.ValueLength);
T resultObject = convertFunc(length.ValueLength);
result.RawObject = resultObject;
result.DisplayValue = toStringFunc == null?result.RawObject.ToString() : toStringFunc(resultObject);
result.IsNull = false;
}
return(new FileStreamReadResult(result, length.TotalLength));
}
/// <summary>
/// Reads the value of a cell from the file wrapper, checks to see if it null using
/// <paramref name="isNullFunc"/>, and converts it to the proper output type using
/// <paramref name="convertFunc"/>.
/// </summary>
/// <param name="offset">Offset into the file to read from</param>
/// <param name="rowId">Internal ID of the row to set on all cells in this row</param>
/// <param name="convertFunc">Function to use to convert the buffer to the target type</param>
/// <param name="isNullFunc">
/// If provided, this function will be used to determine if the value is null
/// </param>
/// <param name="toStringFunc">Optional function to use to convert the object to a string.</param>
/// <param name="setInvariantCultureDisplayValue">Optional parameter indicates whether the culture invariant display value should be provided.</param>
/// <typeparam name="T">The expected type of the cell. Used to keep the code honest</typeparam>
/// <returns>The object, a display value, and the length of the value + its length</returns>
private FileStreamReadResult ReadCellHelper <T>(long offset, long rowId,
Func <int, T> convertFunc,
Func <int, bool> isNullFunc = null,
Func <T, string> toStringFunc = null,
bool setInvariantCultureDisplayValue = false)
{
LengthResult length = ReadLength(offset);
DbCellValue result = new DbCellValue {
RowId = rowId
};
if (isNullFunc == null ? length.ValueLength == 0 : isNullFunc(length.TotalLength))
{
result.RawObject = null;
result.DisplayValue = SR.QueryServiceCellNull;
result.IsNull = true;
}
else
{
AssureBufferLength(length.ValueLength);
fileStream.Read(buffer, 0, length.ValueLength);
T resultObject = convertFunc(length.ValueLength);
result.RawObject = resultObject;
result.DisplayValue = toStringFunc == null?result.RawObject.ToString() : toStringFunc(resultObject);
if (setInvariantCultureDisplayValue)
{
string icDisplayValue = string.Format(System.Globalization.CultureInfo.InvariantCulture, "{0}", result.RawObject);
// Only set the value when it is different from the DisplayValue to reduce the size of the result
//
if (icDisplayValue != result.DisplayValue)
{
result.InvariantCultureDisplayValue = icDisplayValue;
}
}
result.IsNull = false;
}
return(new FileStreamReadResult(result, length.TotalLength));
}
