Repository navigation
Unable to read binary data stored in VARBINARY (n) type fields #1258
Description
Hello,
Unable to read binary data stored in field BlockData VARBINARY (32,765) .
SortedDictionary<short, byte[]> result = [];
foreach (DataRow dataRow in dataTable.Rows)
{
if (dataRow["BlockNo"] is not short blockNo) { continue; }
object objVal = dataRow["BlockData"];
if(objVal is not byte[] blockData) { continue; }
//if (dataRow["BlockData"] is not byte[] blockData) { continue; }
result[blockNo] = blockData;
}
The value of objVal is always the string 'System. Byte []', the value of blockData is always the null.
Thanks a lot.
Alex
Activity
alexluozf commentedon Mar 12, 2026
It's no problem if using FbDbDataReader.
SortedDictionary<short, byte[]> result = [];
while (reader.ReadAsync().Result)
{
short blockNo = reader.GetFieldValue("BlockNo");
byte[] blockData = reader.GetFieldValue<byte[]>("BlockData");
if (blockData != null)
{
result[blockNo] = blockData;
}
}
Thanks a lot.
Alex
cincuranet commentedon Mar 12, 2026
Please provide self-contained runnable code.
alexluozf commentedon Mar 13, 2026
Hello cincuranet,
Please use my test project.
Thanks a lot.
Alex
How to use.zip
FbBinaryFieldAccess.zip
alexluozf commentedon Mar 14, 2026
Hello cincuranet,
Fixed this issue.
method GetSystemType() in src\FirebirdSql.Data.FirebirdClient\Common\DbField.cs
Please review and update the code.
Thanks a lot.
Alex
DbField.zip
alexluozf commentedon Mar 14, 2026
Hello cincuranet,
Should remove case DbDataType.Text.
public Type GetSystemType()
{
switch(DbDataType)
{
case DbDataType.Char:
case DbDataType.VarChar:
{
if(_charset.IsOctetsCharset)
{
return TypeHelper.GetTypeFromDbDataType(DbDataType.Binary);
}
return TypeHelper.GetTypeFromDbDataType(DbDataType);
}
default:
return TypeHelper.GetTypeFromDbDataType(DbDataType);
}
}
DbField.zip