Is it possible to make Select() over Datatable with byte[] array field?

Question

I run a query against a SQL Server for getting a table which contains varbinary columns; the columns are converted to byte array when returned as a datatable.

I am wondering if there is a way to make Select() over System.Byte[] ?

This is what I tried:

byte[] b = (byte[])sessions.table.Rows[72]["security_id"];
string hexString = ByteArrayToHexString(b);
DataRow[] rows = users.table.Select("sid = " + hexString);
// throw exception...
// System.Data.SyntaxErrorException: 'Cannot interpret token '0' at position 7.'

Answer 1

Dunno, but the DataView filter syntax is very obscure and rarely used. Instead just iterate the DataTable.Rows and run the comparison, or use the LINQ extensions and run something like:

var rows = users.table.AsEnumerble().Where(r => r["sid"].SequenceEqual(b)).ToArray();

Answer 2

According to the source , thanks to David Browne, datatable cannot handle binary data with select function, it's not implemented:

internal enum ValueType {
        Unknown = -1,
        Null = 0,
        Bool = 1,
        Numeric = 2,
        Str = 3,
        Float = 4,
        Decimal = 5,
        Object = 6,
        Date = 7,
}

The only solutions are to convert the varbinay to varchar in the server query if you know what the columns are or convert the datatable byte[] columns to string columns on duplicate table and than make the select(), of course other components like linq make it much easier...

Update:

example code how to add new string columns to table and convert the byte[] to string :

private DataTable fixDatatableType(DataTable input) {

 List<DataColumn> overwriteColumnIndex = new List<DataColumn>();
 List<string> addedColumns = new List<string>();

 for (int i = 0; i < input.Columns.Count; i++)
 {
  if (input.Columns[i].DataType == typeof(byte[])) {
      overwriteColumnIndex.Add(input.Columns[i]);
      string newColumnName = input.Columns[i].ColumnName + "_str";
      addedColumns.Add(newColumnName);
      DataColumn dataColumn = new DataColumn(newColumnName, typeof(string));
      input.Columns.Add(dataColumn);
  }
 }

 if (overwriteColumnIndex.Count != 0) {
  for (int z = 0; z < input.Rows.Count; z++)
  {
   DataRow row = input.Rows[z];
   for (int m = 0; m < overwriteColumnIndex.Count; m++)
   {
    if (row[overwriteColumnIndex[m]] != DBNull.Value) {
     row[addedColumns[m]] = 
     ByteArrayToHexString((byte[])row[overwriteColumnIndex[m]]);
    }
   }
  }
 }
 return input;
}