I've been reusing this method of using a DataTable as a parameter to a stored procedure and it's been working great. This is the simplified working code:
using (dbEntities dbe = new dbEntities())
{
var dt = new dataTable();
dt.Columns.Add("ID");
dt.Columns.Add("Message");
dt.Columns.Add("CreatedOn", typeof(DateTime));
foreach (var row in randomDataSource)
{
dt.Rows.Add(
row.id,
row.message,
DateTime.Now
);
}
var tableType = new SqlParameter("tableType", SqlDbType.Structured);
tableType.Value = dt;
tableType.TypeName = "[dbo].[RandomTableType]";
dbe.ExecuteStoreCommand(
"EXEC [dbo].[SaveTable] @tableType",
new object[] { tableType }
);
}
The problem arises when the field I want to add is of a binary type. i.e.:
dt.Columns.Add("BinaryMessage", typeof(byte[]));
The corresponding column in the database is varbinary(MAX)
by the way. When I try to run this, I get this error:
Implicit conversion from data type nvarchar(max) to varbinary(max) is not allowed. Use the CONVERT function to run this query.
How do I modify what I have to make this work?
The representation for a binary string in .NET is the SqlBinary
structure.
You want to add your column like this:
dt.Columns.Add("BinaryMessage", typeof(SqlBinary));
The SqlBinary
class has an explicit conversion to a byte array and an implicit conversion from a byte array, so the value from a byte array to the column is a simple matter of assignment, while getting a byte array from the column requires an explicit cast.