Use a table-valued parameter for your stored procedure.
When you pass it in from C# you'll add the parameter with the data type of SqlDb.Structured.
See here: http://msdn.microsoft.com/en-us/library/bb675163.aspx
Example:
// Assumes connection is an open SqlConnection object.
using (connection)
{
// Create a DataTable with the modified rows.
DataTable addedCategories =
CategoriesDataTable.GetChanges(DataRowState.Added);
// Configure the SqlCommand and SqlParameter.
SqlCommand insertCommand = new SqlCommand(
"usp_InsertCategories", connection);
insertCommand.CommandType = CommandType.StoredProcedure;
SqlParameter tvpParam = insertCommand.Parameters.AddWithValue(
"@tvpNewCategories", addedCategories);
tvpParam.SqlDbType = SqlDbType.Structured;
// Execute the command.
insertCommand.ExecuteNonQuery();
}