/// <summary>
/// 逐行读取属性记录信息
/// </summary>
/// <returns></returns>
public DataRow GetNextRow()
{
var fieldInfos = _header.FieldInfos;
if (_dbfTable == null)
{
_dbfTable = new DataTable();
foreach (var fieldInfo in fieldInfos)
{
_dbfTable.Columns.Add(fieldInfo.FieldName, FieldTypeTransform.DbfFieldType2CSharpType(fieldInfo));
}
//跳过文件头
_reader.BaseStream.Seek(_header.HeaderLength, SeekOrigin.Begin);
}
var dtRow = _dbfTable.NewRow();
_curRowIndex++;
if (_curRowIndex > _header.RecordCount)
{
dtRow = null;
}
else
{
if (_reader.PeekChar() == '*') // DELETED
{
dtRow = null;
}
else
{
var fieldStartIndex = 1;
var row = _reader.ReadBytes(_header.RecordLength);
foreach (var field in fieldInfos)
{
byte[] buffer = new byte[field.FieldLength];
//(Array sourceArray, int sourceIndex, Array destinationArray, int destinationIndex, int length)
Array.Copy(row, fieldStartIndex, buffer, 0, field.FieldLength);
fieldStartIndex += field.FieldLength;
string text = (Encoding.GetString(buffer) ?? String.Empty).Trim().Replace("\0", "");
var valueObj = GetValueObj(field, text, buffer);
dtRow[field.FieldName] = valueObj;
}
_dbfTable.Rows.Add(dtRow);
}
}
return(dtRow);
}
/// <summary>
/// 构建文件头字节数组
/// </summary>
/// <returns></returns>
private (byte[], short) BuildFieldType()
{
var result = new byte[_dataColumns.Count * 32];
int oneRecordLength = 0;
for (int i = 0; i < _dataColumns.Count; i++)
{
//当前列信息
var column = _dataColumns[i];
var curColumnInfo = new byte[32];
//列名
var fieldNameLength = 11;
var fieldName = _encoding.GetBytes(column.ColumnName + "\0");
if (fieldName.Length >= fieldNameLength)
{
Buffer.BlockCopy(fieldName, 0, curColumnInfo, 0, fieldNameLength);
}
else
{
Buffer.BlockCopy(fieldName, 0, curColumnInfo, 0, fieldName.Length);
var remainderLength = fieldNameLength - fieldName.Length;
var remainderBytes = new byte[remainderLength];
for (int j = 0; j < remainderLength; j++)
{
remainderBytes[j] = 0;
}
Buffer.BlockCopy(remainderBytes, 0,
curColumnInfo, fieldName.Length,
remainderBytes.Length);
}
//列类型
var dbfFieldInfo
= FieldTypeTransform
.CSharpType2DbfFieldInfoWithoutName(column.DataType);
var dbfFieldType = dbfFieldInfo.FieldType;
var fieldLength = dbfFieldInfo.FieldLength;
var accuracy = dbfFieldInfo.Accuracy;
_fieldInfos.Add(dbfFieldInfo);
var dbfType = _encoding.GetBytes(dbfFieldType.ToString())[0];
curColumnInfo[11] = dbfType;
//保留字节 12-15
Buffer.BlockCopy(BitConverter.GetBytes(0), 0,
curColumnInfo, 12, 4);
curColumnInfo[16] = fieldLength; //fieldLength
curColumnInfo[17] = accuracy; //accuracy
oneRecordLength += fieldLength;
//18-31 填充0
for (int j = 18; j < 32; j++)
{
curColumnInfo[j] = 0;
}
var offset = i * 32;
Buffer.BlockCopy(curColumnInfo, 0, result, offset, 32);
}
oneRecordLength += 1;//控制位
return(result, (short)oneRecordLength);
}
