SqlParameter 操作 image 字段

public static void AddEmployee(  
  string lastName,   
  string firstName,   
  string title,   
  DateTime hireDate,   
  int reportsTo,   
  string photoFilePath,   
  string connectionString)  
{  
  byte[] photo = GetPhoto(photoFilePath);  
  
  using (SqlConnection connection = new SqlConnection(  
    connectionString))  
  
  SqlCommand command = new SqlCommand(  
    "INSERT INTO Employees (LastName, FirstName, " +  
    "Title, HireDate, ReportsTo, Photo) " +  
    "Values(@LastName, @FirstName, @Title, " +  
    "@HireDate, @ReportsTo, @Photo)", connection);   
  
  command.Parameters.Add("@LastName",    
     SqlDbType.NVarChar, 20).Value = lastName;  
  command.Parameters.Add("@FirstName",   
      SqlDbType.NVarChar, 10).Value = firstName;  
  command.Parameters.Add("@Title",       
      SqlDbType.NVarChar, 30).Value = title;  
  command.Parameters.Add("@HireDate",   
       SqlDbType.DateTime).Value = hireDate;  
  command.Parameters.Add("@ReportsTo",   
      SqlDbType.Int).Value = reportsTo;  
  
  command.Parameters.Add("@Photo",  
      SqlDbType.Image, photo.Length).Value = photo;  
  
  connection.Open();  
  command.ExecuteNonQuery();  
  }  
}  
  
public static byte[] GetPhoto(string filePath)  
{  
  FileStream stream = new FileStream(  
      filePath, FileMode.Open, FileAccess.Read);  
  BinaryReader reader = new BinaryReader(stream);  
  
  byte[] photo = reader.ReadBytes((int)stream.Length);  
  
  reader.Close();  
  stream.Close();  
  
  return photo;  
}  

from: https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/sql/inserting-an-image-from-a-file