C#.net，通过存储过程更新数据库时出错

你好！我是c#.net初学者

**my Store procedure:** 

USE [DB_COUNTERINTELLIGENCE]
GO
/****** Object:  StoredProcedure [dbo].[Updatederogatory]    Script Date: 2015/6/12 1:21:24 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:        <Author,,Name>
-- Create date: <Create Date,,>
-- Description:   <Description,,>
-- =============================================
ALTER PROCEDURE [dbo].[Updatederogatory]
  @ID int,
  @txtid int,
  @Firstname varchar(30),
  @Middlename varchar(30),
  @Lastname varchar(30),
  @Company varchar(50),
  @Department varchar(40),
  @Position varchar(40),
  @Violation text,
  @DateCommitted date,
  @TimeCommitted nchar(10),
  @Remarks text,
  @Activities text,
  @Violation2 text,
  @DateCommitted2 date,
  @TimeCommitted2 nchar(10),
  @Remarks2 text,
  @Activities2 text,
  @Violation3 text,
  @DateCommitted3 date,
  @TimeCommitted3 nchar(10),
  @Remarks3 text,
  @Activities3 text,
  @Images image
AS
BEGIN
  SET NOCOUNT ON;

UPDATE tbl_decimaly SET Firstname=@Firstname，Middlename=@Middlename，Lastname=@姓氏，Company=@公司，部门=@部门，职位=@职位，违规=@违规，DateCommitted=@DateCommitted，TimeCommitted=@TimeCommitted，备注=@备注，活动=@活动，违规2=@Violation2，DateCommitted2=@DateCommitted2，TimeCommitted2=@TimeCommitted2，Remarks2=@Remarks2，Activities2=@Activities2，Violation3=@Violation3，DateCommitted3=@DateCommitted3，TimeCommitted3=@TimeCommitted3，Remarks3=@Remarks3，Activities3=@Activities3，Images=@Images WHERE ID=@txtid END

**Here is my code:**
    > if (txtid.Text == "")
    >             {
    >                 MessageBox.Show("Require ID is a must, Please Registered again for your ID", "ERROR", MessageBoxButtons.OK,
    > MessageBoxIcon.Error);
    >             }
    >             else if (txtfirstname.Text == "")
    >             {
    >                 MessageBox.Show("Your name is missing", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
    > 
    >             }
    >             else if (txtlastname.Text == "")
    >             {
    >                 MessageBox.Show("Your Last name is missing", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
    >             }
    >             else if (txtmiddlename.Text == "")
    >             {
    >                 MessageBox.Show("Your Middle name is missing", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
    >             }
    >             else
    >             {
    >                 try
    >                 {
    >                     byte[] img = null;
    >                     FileStream fs = new FileStream(imageLocation, FileMode.Open, FileAccess.Read);
    >                     BinaryReader br = new BinaryReader(fs);
    >                     img = br.ReadBytes((int)fs.Length);
    > 
    >                     SqlConnection con = new SqlConnection(cs);
    >                     SqlCommand cmd = new SqlCommand();
    >                     cmd.Connection = con;
    >                     cmd.CommandType = CommandType.StoredProcedure;
    >                     cmd.CommandText = "Updatederogatory";
    >                     cmd.Parameters.AddWithValue("@ID", txtid.Text);
    >                     cmd.Parameters.AddWithValue("@Firstname", txtfirstname.Text);
    >                     cmd.Parameters.AddWithValue("@Middlename", txtmiddlename.Text);
    >                     cmd.Parameters.AddWithValue("@Lastname", txtlastname.Text);
    >                     cmd.Parameters.AddWithValue("@Company", combocompany.Text);
    >                     cmd.Parameters.AddWithValue("@Department", comboDepartment.Text);
    >                     cmd.Parameters.AddWithValue("@Position", txtposition.Text);
    > 
    >                     cmd.Parameters.AddWithValue("@Violation", richviolation.Text);
    >                     cmd.Parameters.AddWithValue("@DateCommitted ", datecommitted.MaxDate);
    >                     cmd.Parameters.AddWithValue("@TimeCommitted", timecommitted.Text);
    >                     cmd.Parameters.AddWithValue("@Remarks", richremarks.Text);
    >                     cmd.Parameters.AddWithValue("@Activities", richderoactivities.Text);
    > 
    >                     cmd.Parameters.AddWithValue("@Violation2", richviolation2.Text);
    >                     cmd.Parameters.AddWithValue("@DateCommitted2", datecommitted2.MaxDate);
    >                     cmd.Parameters.AddWithValue("@TimeCommitted2", timecommitted2.Text);
    >                     cmd.Parameters.AddWithValue("@Remarks2", richremarks2.Text);
    >                     cmd.Parameters.AddWithValue("@Activities2", richactivities2.Text);
    > 
    >                     cmd.Parameters.AddWithValue("@Violation3", richviolation2.Text);
    >                     cmd.Parameters.AddWithValue("@DateCommitted3", datecommitted2.MaxDate);
    >                     cmd.Parameters.AddWithValue("@TimeCommitted3", timecommitted2.Text);
    >                     cmd.Parameters.AddWithValue("@Remarks3", richremarks2.Text);
    >                     cmd.Parameters.AddWithValue("@Activities3", richactivities3.Text);
    >                     con.Open();
    >                     cmd.Parameters.Add(new SqlParameter("@Images", img));
    >                     cmd.ExecuteNonQuery();
    >                     con.Close();
    >                     MessageBox.Show("Successfully Updated");
    >                 }
    >                 catch (Exception ex)
    >                 {
    > 
    >                     MessageBox.Show(ex.Message);
    >                 }

}

我的问题是，当我点击更新按钮时，消息框将弹出并写下错误"空路径名称不合法"。。

如何解决这个问题？