sql读写图片时Image.FromStream方法提示参数错误问题解决

我们通常这么写

using (SqlDataReader drm = sqlComm.ExecuteReader())
                     {
                         drm.Read();//以下把数据库中读出的Image流在图片框中显示出来.
 
                        MemoryStream ms = new MemoryStream((byte[])drm["Logo"]);
                         Image img = Image.FromStream(ms);
 
                        this.pictureBox1.Image = img;
                     }

我的写数据

        private void btnOK_Click(object sender, EventArgs e)
        {
            string name = "";
            if (tbxUserName.Text.Trim() == "")
            {
                MessageBox.Show("姓名不能为空，请重新输入！", "提示");
                return;
            }
            else
            {
                name = tbxUserName.Text.Trim();
            }

            string group = "";
            if (cbxGroup.Text.Trim() == "")
            {
                group = "未分组";
            }
            else
            {
                group = cbxGroup.Text.Trim();
            }
            string phone = tbxTel.Text.Trim();
            string workunit = tbxWorkUnit.Text.Trim();
            string email = tbxEmail.Text.Trim();
            string qq = tbxQQ.Text.Trim();
            byte[] b = null;
            if (txtFilePath != "")
            {
                try
                {
                    FileStream fs = new FileStream(txtFilePath, FileMode.Open, FileAccess.Read);//类型为打开数据 权限为只读 不呢写数据
                    int length = Convert.ToInt32(fs.Length);
                    b = new byte[length];
                    fs.Read(b, 0, length);//数据读入b数组中 从0号到length位
                    fs.Close();//关闭输入输出流
                }
                catch (Exception ex)
                {
                    b = null;
                    MessageBox.Show(ex.Message);
                }
            }
            else 
            {
                b = pixData;
            }
            try
            {
                using (SqlConnection connection = new SqlConnection(connectionString))
                {
                    //获取当前的数据在表中的ID
                    SqlCommand commandInsert = new SqlCommand();
                    commandInsert.Connection = connection;

                    //connection.Close();
                    connection.Open();
                    //插入数据
                    commandInsert.CommandText = "USE db_TXL UPDATE tb_BusicInfo set Groups= @Groups ,Name=@Name,WorkUnit=@WorkUnit,Phone=@Phone,Email=@Email,QQ=@QQ,Picture=@Picture";
                    commandInsert.CommandText += "  where ID=@ID ";

                    commandInsert.Parameters.Add("@ID", SqlDbType.Int);
                    commandInsert.Parameters.Add("@Groups", SqlDbType.VarChar, 50);
                    commandInsert.Parameters.Add("@Name", SqlDbType.VarChar, 20);
                    commandInsert.Parameters.Add("@WorkUnit", SqlDbType.VarChar, 50);
                    commandInsert.Parameters.Add("@Phone", SqlDbType.VarChar, 14);
                    commandInsert.Parameters.Add("@Email", SqlDbType.VarChar, 50);
                    commandInsert.Parameters.Add("@QQ", SqlDbType.VarChar, 20);
                    commandInsert.Parameters.Add("@Picture", SqlDbType.Image);//Image的类型不能写错！！

                    commandInsert.Parameters["@ID"].Value = ID;
                  //  commandInsert.Parameters["@UserName"].Value = strUserName;
                    commandInsert.Parameters["@Groups"].Value = group;
                    commandInsert.Parameters["@Name"].Value = name;
                    commandInsert.Parameters["@WorkUnit"].Value = workunit;
                    commandInsert.Parameters["@Phone"].Value = phone;
                    commandInsert.Parameters["@Email"].Value = email;
                    commandInsert.Parameters["@QQ"].Value = qq;
                    //commandInsert.Parameters[""].Value=;
                    if (txtFilePath == "" && pixData==null)
                    {
                        commandInsert.Parameters["@Picture"].Value = DBNull.Value;//DBNull  不存在的值NULL
                    }
                    else
                    {
                        commandInsert.Parameters["@Picture"].Value = b;
                    }
                    commandInsert.ExecuteNonQuery();
                    connection.Close();
                    DialogResult = DialogResult.OK;
                }
            }
            catch (Exception ex) { MessageBox.Show(ex.Message); }
        }

我的读数据

     private void frmEdit_Load(object sender, EventArgs e)
        {
            try
            {
                using (SqlConnection connection = new SqlConnection(connectionString))
                {
                    string commandString = "select * from tb_BusicInfo where ID= " + ID.ToString() + " ";
                    SqlCommand command = new SqlCommand(commandString, connection);
                    connection.Open();
                    SqlDataReader reader = command.ExecuteReader();
                    if (reader.Read())
                    {
                        tbxUserName.Text = Convert.ToString(reader["Name"]);
                        cbxGroup.Text = Convert.ToString(reader["Groups"]);
                        tbxTel.Text = Convert.ToString(reader["Phone"]);
                        tbxWorkUnit.Text = Convert.ToString(reader["WorkUnit"]);
                        tbxEmail.Text = Convert.ToString(reader["Email"]);
                        tbxQQ.Text = Convert.ToString(reader["QQ"]);
                        if (reader["Picture"] == DBNull.Value)
                        {
                            pbxPicture.Image = TongXunLu.Properties.Resources.defaultPix;
                        }
                        else
                        {
                           // string a=reader["Picture"].ToString();
                         //  byte[] b = (byte[])((reader["Picture"]));
                           MemoryStream buf = new MemoryStream((byte[])reader["Picture"]);
                            Image image = Image.FromStream(buf);
                            Bitmap bt = new Bitmap(image);
                            pbxPicture.Image = bt;
                            //pbxPicture.Image = image;
                          //  pbxPicture.Image = Image.FromStream(new MemoryStream(b));//把二进制流读出来??问题
                        }
                    }
                    reader.Close();
                    connection.Close();

                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

读数据的时候，但是在写数据的时候可能发生了一些错误。

果然我在追寻byte[]的数组的时候发现 写的时候有2万多个 读的时候只有50个

于是我想可能是写的时候出了问题，于是

commandInsert.Parameters.Add("@Picture", SqlDbType.Image,50);

改为commandInsert.Parameters.Add("@Picture", SqlDbType.Image);

照片可以正常显示了

参考了http://blog.csdn.net/zystory/article/details/4399338

你存数据的时候出了问题，和读数据没有关系
new SqlParameter("@L_RolePic", SqlDbType.Image, 16) 改为 new SqlParameter("@L_RolePic", SqlDbType.Image),

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