Insert many rows with Dapper

Agree with DaniCE, SqlBulkCopy is the way to go here. Been in that situation lately where I did most of the data work with dapper but with larger amounts of data, in my case millions of records, Dapper was for once not my best friend.

    private void BulkCopy(SqlConnection sqlConnection,string tableName, DataTable dataTable)
    {
        using (var bulkCopy = new SqlBulkCopy(sqlConnection))
        {
            bulkCopy.DestinationTableName = tableName;
            bulkCopy.BatchSize = 50000;
            bulkCopy.BulkCopyTimeout = 60; //seconds

            bulkCopy.WriteToServer(dataTable);
        }
    }