CODEWITHSUNDEEP
c#sqlsql-server
luciacar
luciacar

Reputation: 51

No mapping exists from object type System.__ComObject to a known managed provider native type. c#

I want to upload a pdf file from a scanner into a database (SQL Server), but I get the error message:

System.ArgumentException: 'No mapping exists from object type System.__ComObject to a known managed provider native type.'

I'm using Visual Studio 2019.

This is my code:

escanerDisponible = manejadorDisp.DeviceInfos[i];

Device dispositivo = escanerDisponible.Connect();
Item objetoEscaneado = dispositivo.Items[1];

Escaner.AjustesEscaner(objetoEscaneado, resolucion, 0, 0, width, height, 0, 0, color);

con.Open();
SqlCommand inserta = new SqlCommand("UPDATE inspeccionGestionDocumental SET numeroInspeccion = numeroInspeccion, numeroPropuesta = numeroPropuesta, placa = placa, documento = @documento WHERE placa ='" + tNumeroPlaca.Text + "'AND numeroPropuesta ='" + tNumeroPropuesta.Text + "';", con);
inserta.Parameters.AddWithValue("@documento", objetoEscaneado);
SqlParameter addDocumento = new SqlParameter("@documento", objetoEscaneado);
addDocumento.Direction = ParameterDirection.Output;

inserta.ExecuteReader();

MemoryStream ms = new MemoryStream();

inserta.ExecuteReader().Read();
var bytes = new Byte[(inserta.ExecuteReader().GetBytes(0, 0, null, 0, int.MaxValue))];
inserta.ExecuteReader().GetBytes(0, 0, bytes, 0, bytes.Length);
ms.Write(bytes, 0, bytes.Length);

MessageBox.Show("Documento insertado");
con.Close();

Upvotes: 1

Views: 3212

Answers (1)

Heinzi
Heinzi

Reputation: 172280

Here:

inserta.Parameters.AddWithValue("@documento", objetoEscaneado);

You add an object of type Item as a parameter to your SQL. ADO.NET does not know how to convert Item into a data type that SQL Server understands ("a known managed provider native type"), which is why you get the error message.

To fix this, use a data type that SQL Server understands (for example, a string or a byte array) instead. I am not familiar with the library you use, but it's very likely that Item has a property or method that allows you to access the document as a byte array.

Oh, and as a side note: Please use parameters for your WHERE parameters as well, see this question for details:

Upvotes: 2

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